I have also such kind of scope, old, but do well, electronics stay fine plastic case do fall apart.
Attachments
I always add a bleeder resistor with an LED in series so I can see if the amp is still charged.
I remember my first valve pre amp build. I built it up and it didn't work so I turned it off and touched the circuit and got a huge shock. My tutor said I had to discharge the smoothing cap. So next time I shorted out smoothing cap with a resistor. I touch circuit and got a huge shock again, I had forgot to turn it off !
Amazingly, I am now 63 but much more careful.
I remember my first valve pre amp build. I built it up and it didn't work so I turned it off and touched the circuit and got a huge shock. My tutor said I had to discharge the smoothing cap. So next time I shorted out smoothing cap with a resistor. I touch circuit and got a huge shock again, I had forgot to turn it off !
Amazingly, I am now 63 but much more careful.
Some of my early SMPS designs were a bit touchy and I occasionally had exploding mosfets flying around the room. I used to turn it on from behind a chair to shield me from flying mosfets. What I did in the end was an overcurrent detect circuit on the mosfets.
I used a PIC micro to do the LLC frequencies and this had an input pin for over current detect. I also had an LED output to show if there was an overload. If the PIC detected overload it immediately turned everything off.
I used a PIC micro to do the LLC frequencies and this had an input pin for over current detect. I also had an LED output to show if there was an overload. If the PIC detected overload it immediately turned everything off.
We have a lot of smps controllers, and when do it right and use a isolation transfrormer things go right, deadtimes are the most underestimated errors.
slowly set voltage up helps, use of a pic is is not suitable for everywhone, need to program.
I have some parts, fase shift controllers and resonant, and is a NC1365.
regards.
slowly set voltage up helps, use of a pic is is not suitable for everywhone, need to program.
I have some parts, fase shift controllers and resonant, and is a NC1365.
regards.
I was a PIC consultant for 13 years so have used them extensively. The program is pretty simple. It just looks at feedback signal. If the feedback is low it decreases LLC frequency. If the feedback is high it increases LLC frequency. If it sees a over load it turns off IR2113 and puts on over load LED. Must be less than 200 lines.
Code:
#include p16f506.inc
LIST R=DEC
; LIST
;----- CONFIG Options --------------------------------------------------
;_OSC_LP EQU H'0FF8' ; LP oscillator and 18 ms DRT
;_LP_OSC EQU H'0FF8' ; LP oscillator and 18 ms DRT
;_OSC_XT EQU H'0FF9' ; XT oscillator and 18 ms DRT
;_XT_OSC EQU H'0FF9' ; XT oscillator and 18 ms DRT
;_OSC_HS EQU H'0FFA' ; HS oscillator and 18 ms DRT
;_HS_OSC EQU H'0FFA' ; HS oscillator and 18 ms DRT
;_OSC_EC EQU H'0FFB' ; EC Osc With RB4 and 1.125 ms DRT
;_EC_OSC EQU H'0FFB' ; EC Osc With RB4 and 1.125 ms DRT
;_OSC_IntRC_RB4EN EQU H'0FFC' ; INTRC With RB4 and 1.125 ms DRT
;_IntRC_OSC_RB4EN EQU H'0FFC' ; INTRC With RB4 and 1.125 ms DRT
;_OSC_IntRC_CLKOUTEN EQU H'0FFD' ; INTRC With CLKOUT and 1.125 ms DRT
;_IntRC_OSC_CLKOUTEN EQU H'0FFD' ; INTRC With CLKOUT and 1.125 ms DRT
;_OSC_ExtRC_RB4EN EQU H'0FFE' ; EXTRC With RB4 and 1.125 ms DRT
;_ExtRC_OSC_RB4EN EQU H'0FFE' ; EXTRC With RB4 and 1.125 ms DRT
;_OSC_ExtRC_CLKOUTEN EQU H'0FFF' ; EXTRC With CLKOUT and 1.125 ms DRT
;_ExtRC_OSC_CLKOUTEN EQU H'0FFF' ; EXTRC With CLKOUT and 1.125 ms DRT
;_WDT_OFF EQU H'0FF7' ; WDT disabled
;_WDT_ON EQU H'0FFF' ; WDT enabled
;_CP_ON EQU H'0FEF' ; Code protection on
;_CP_OFF EQU H'0FFF' ; Code protection off
;_MCLRE_OFF EQU H'0FDF' ; RB3/MCLR pin functions as RB3, MCLR tied internally to VDD
;_MCLRE_ON EQU H'0FFF' ; RB3/MCLR pin functions as MCLR
;_IOSCFS_OFF EQU H'0FBF' ; 4 MHz INTOSC Speed
;_IOSCFS_ON EQU H'0FFF' ; 8 MHz INTOSC Speed
;20MHZ
__CONFIG _MCLRE_OFF & _WDT_ON & _CP_OFF & _OSC_HS
;*****************************************
;SUBWF FLAGS
;IF W > MEM THEN NC
;IF W = MEM THEN C
;IF W < MEM THEN C
;IF W<= MEM THEN C
;IF MEM>=W THEN C
;IF MEM<W THEN NC
;*****************************************
#DEFINE SET0 1
#DEFINE SET1 2
#DEFINE SET2 4
#DEFINE SET3 8
#DEFINE SET4 16
#DEFINE SET5 32
#DEFINE SET6 64
#DEFINE SET7 128
#DEFINE LED PORTB,0
#DEFINE OPTOINPUT PORTB,1
#DEFINE NOTOVERCURRENT PORTB,2
;PORTC = GATES
FIRSTRAM EQU 0XD ;16F506 RAM START ADDRESS
;10H TO 1FH IN BANK 0
CBLOCK FIRSTRAM
TEMP
TEMP1
TEMP2
TEMPL
TEMPM
PULSES
ENDC
ORG 0
INCLUDE MACRO.ASM
CLRWDT
CLRF FSR ;BANK 0 RAM
MOVWF OSCCAL ;SET UP OSC FREQ ACCURATELY
MOVLW 0X30 ;A2D ALL OFF
MOVWF ADCON0
CLRF PORTC ;ALL MOSFETS OFF
MOVLW 0
TRIS PORTC
CLRF PORTB ;LED OFF
MOVLW SET1+SET2 ; OPTO AND NOTOVERCURRENT ARE INPUTS
TRIS PORTB
MOVLW 0X41 ;COMPARATORS OFF
MOVWF CM1CON0
MOVWF CM2CON0
CLRF VRCON
MOVLW 0XC0 ;DISABLE WEAK PULL UPS ON PORTB
OPTION
;WAIT 4 SECS TO LET POWER SUPPLY CAPS CHARGE UP
MOVLW 4
CALL WAITWSECONDS
;**********
;SOFT START
;**********
RESTART
MOVLW 0
MOVWF TEMPL
MOVLW 20 ;20ms
MOVWF TEMPM
SOFTSTART ;166KHz 30 cycle loop
MOVLW 1
CLRF PORTC ;DEADTIME
NOP ;DEADTIME
MOVWF PORTC
;HAVE TO IGNORE OVER CURRENT HERE as s/c to start with
CLRWDT
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
MOVLW 2
CLRF PORTC ;DEADTIME
NOP ;DEADTIME
MOVWF PORTC
;;;;;;;;
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
DECFSZ TEMPL,F
GOTO SOFTSTART
DECFSZ TEMPM,F
GOTO SOFTSTART
;*************************************************
;based on 30uh leakage inductance Lr, Lm =155uH and 200nf Cr
;*************************************************
ON BSF LED ;POWERED UP OK
MLOOP
BTFSC OPTOINPUT
GOTO SLOWCLOCK ;GO IF OPTO HIGH (VOLTS TOO LOW)
;;;;;;;;;;;;;;;;;;;;;;;;;;
;FASTCLOCK
; 166KHZ 2 * 15 CYCLE LOOP
FASTCLOCK
CLRF PORTC ;DEADTIME
MOVLW 1 ;DEADTIME
MOVWF PORTC
;;;;;;;;;;;;
CLRWDT ;LET SETTLE 800ns
NOP
NOP
NOP
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
CLRF PORTC ;DEADTIME
MOVLW 2 ;DEADTIME
MOVWF PORTC
;;;;;;;;;;;;
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
GOTO MLOOP
;*************************
;125KHZ 2* 20 CYCLE LOOP
SLOWCLOCK
CLRF PORTC ;DEADTIME
MOVLW 1 ;DEADTIME
MOVWF PORTC
;;;;;;;;;;;;
CLRWDT ;LET SETTLE 800nS
NOP
NOP
NOP
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
BTFSS NOTOVERCURRENT ;GO IF OVER CURRENT
GOTO BROKEN
NOP
CLRF PORTC ;DEADTIME
MOVLW 2 ;DEADTIME
MOVWF PORTC
;;;;;;;;;;;;
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
GOTO MLOOP
;************************
;SLOW FLASH LED
BROKEN CLRF PORTC ;MOSFETS OFF
BSF LED
CALL WAIT250MS
CALL WAIT250MS
CALL WAIT250MS
CALL WAIT250MS
BCF LED
CALL WAIT250MS
CALL WAIT250MS
CALL WAIT250MS
CALL WAIT250MS
GOTO BROKEN
;******************************************
;FAST FLASH LED
BROKENSOFT CLRF PORTC ;MOSFETS OFF
BSF LED
CALL WAIT250MS
BCF LED
CALL WAIT250MS
GOTO BROKENSOFT
;******************************************
;63 max input
WAITWSECONDS MOVWF TEMP2
CLRC
RLF TEMP2,F ;*2
RLF TEMP2,W ;*4
GOTO SECS
WAIT1SECOND
MOVLW 4
SECS MOVWF TEMP2
L3
MOVLW 250 ;250MS LOOP
MOVWF TEMP1
L2
MOVLW 250 ;1 MS LOOP
MOVWF TEMP
L1 CLRWDT ;10 CYCLE LOOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
DECFSZ TEMP,F
GOTO L1
DECFSZ TEMP1,F
GOTO L2
DECFSZ TEMP2,F
GOTO L3
RETLW 0
;************************************
WAIT1MS MOVLW 250
MOVWF TEMP
W1M CLRWDT ;20 CYCLE LOOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
DECFSZ TEMP,F
GOTO W1M
RETLW 0
;***********************************
WAIT250MS MOVLW 250
MOVWF TEMP2
W2M CALL WAIT1MS
DECFSZ TEMP2,F
GOTO W2M
RETLW 0
;*************************************
WAIT50MS MOVLW 50
MOVWF TEMP2
W2M50 CALL WAIT1MS
DECFSZ TEMP2,F
GOTO W2M50
RETLW 0
;*************************************Thanks nigelwright, is program free? I will test it just curious what it does, I have a while ago search a program for a smps mig welder, I did now put in a big transformer, but smps is mucho better, maybe you now a solution, I think even this program because it has feedback is usable, I need then a very stable and clean supply for the pic, otherwise with welding spikes can kill it or disturb program whit desastreus consequenses for the smps itselfs, I have programmers for most of these chips.
Driving the mosfets needs then a couple of transistors in totempole and a driver transformer, because these pic has not enough current and are not designed for that.
In principle you do jus emulate a normal chip and have now own control, completely, I do see also other chips who are be used I have somewhere a program for that who do mig for example, on a atmegachip. I do find pic more easy.
I have to look at the transformer, because the primairy is quite low in induction, and I need to fill the coilformer, winding these need some experience.
As programming concerns, I can not do that, never learning that, and not so easy as I get older, now almost 63.
But I did undo hasp dongles in past and even everkey, so the NOP I see in your programs is much used that day
But times a changed, it is not interesting anymore to play with that, and it is years ago.
thanks for the info,
kees
Driving the mosfets needs then a couple of transistors in totempole and a driver transformer, because these pic has not enough current and are not designed for that.
In principle you do jus emulate a normal chip and have now own control, completely, I do see also other chips who are be used I have somewhere a program for that who do mig for example, on a atmegachip. I do find pic more easy.
I have to look at the transformer, because the primairy is quite low in induction, and I need to fill the coilformer, winding these need some experience.
As programming concerns, I can not do that, never learning that, and not so easy as I get older, now almost 63.
But I did undo hasp dongles in past and even everkey, so the NOP I see in your programs is much used that day
But times a changed, it is not interesting anymore to play with that, and it is years ago.thanks for the info,
kees
Attachments
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I think the wisdom in this forum was in the first couple of pages. By the way 1000v-1500v is not 'ultra-high' voltage' it is 'technically' high voltage. Sage advice, with the occasional error commenced this forum however noted in one post 'wiring rated at 250V' was cautioned when running at say 1000V...very true but also much wiring, components such as tag strips, stand-off insulators and terminals (various coloured and sized lugs) are rated at ELV (extra low voltage) owing to the widespread use of solid state material in dyi...rarely exceeding 100v on the electronics and generally around 14V.
The comment about death dealing TV's somewhere on the forum relates to any equipment which is transformer-less, usually old USA/UK costs-saving junk production mentality. An indication of astounding stupidity in poor safety and unreliability was the much hailed....much reviled.... Drake R4-C receiver whish used a resistor to drop 150V to 12v...or 10 when its power gobbling class A amp was driven. The power supplies simply burned out. Better supplies were created for after market but one could spend well over $1000US to 'tweak' the receiver into 'top drawer' (when the real problem was a time-only fix needed in one IF transformer circuit). The primary 'tweaker' claimed his supply did not use resistors to lower the voltage...interesting ...so what happened to the balance of 136 volts when utilising a regulator?...
My ART-13 Collins transmitter uses a 1400volt supply and some people run them (power mad) to 2000V. Such supplies should be not open buy inside a cage with wiring...including filaments, rated to in excess of 2kV. One of the most brilliant designs ever from Collins it was expected that only Collins or Military trained people would service them. I'm repairing- recapping-re-component-ing (for sale) at least 20 WW11 radios. It requires working on them live when fault finding and the risk is quite high...a moment of
concentration loss...or a spasm could kill me. Someone during the forum mentioned an isolating transformer, wondering what it does....It's seful for keeping mains noise 'down' and isolating us from part of the problem with American sets where one mains cable (Russian roulette) goes to unearthed chassis. It also stops operation of the RCD if one contacts the line side of supply. Some 'isolation transformers (particularly 240-110v) have been notdouble wound but single wound and tapped ...such Auto-transformers are a menace. and banned in Australia...but who knows what migrants bring here then flog later. Working on mains-operated sets, particularly valve setsshold be done with insulating footwear, a rubber mat and long sleeves...the sad part is that even protected from an earth conductivity that way, contacting low voltage (110-1000V) usually is with the other hand or arm to chassis and whether 'mains' earthed or B+ negative you will become a part of the circuit.
In closing...wallops from charged electrolytics are not microsecond experiences. They can do serious damage, even kill. Do NOT discharge them using a short to chasis...that begins to destroy the capacitor. Place a high value, adequate resistor..e.g. 20k or so across the cap (use say 5W) and nevertheless...check voltage as a matter of high-awareness/precautionary , self-respecting habit. Check that resistor from time to time also...it may fail or substantially change value.
Never work on a set 'turned-on' if possible to not do so. Pull the plug from the mains supply..not just turn off the set. Work mindfully. Try not to work alone, or at least advise family of what you are doing and leave your door open so they can check on you unobtrusively and hear you scream if' hooked-up' or getting an electrolytic discharge.. and you WILL scream.
The comment about death dealing TV's somewhere on the forum relates to any equipment which is transformer-less, usually old USA/UK costs-saving junk production mentality. An indication of astounding stupidity in poor safety and unreliability was the much hailed....much reviled.... Drake R4-C receiver whish used a resistor to drop 150V to 12v...or 10 when its power gobbling class A amp was driven. The power supplies simply burned out. Better supplies were created for after market but one could spend well over $1000US to 'tweak' the receiver into 'top drawer' (when the real problem was a time-only fix needed in one IF transformer circuit). The primary 'tweaker' claimed his supply did not use resistors to lower the voltage...interesting ...so what happened to the balance of 136 volts when utilising a regulator?...
My ART-13 Collins transmitter uses a 1400volt supply and some people run them (power mad) to 2000V. Such supplies should be not open buy inside a cage with wiring...including filaments, rated to in excess of 2kV. One of the most brilliant designs ever from Collins it was expected that only Collins or Military trained people would service them. I'm repairing- recapping-re-component-ing (for sale) at least 20 WW11 radios. It requires working on them live when fault finding and the risk is quite high...a moment of
concentration loss...or a spasm could kill me. Someone during the forum mentioned an isolating transformer, wondering what it does....It's seful for keeping mains noise 'down' and isolating us from part of the problem with American sets where one mains cable (Russian roulette) goes to unearthed chassis. It also stops operation of the RCD if one contacts the line side of supply. Some 'isolation transformers (particularly 240-110v) have been notdouble wound but single wound and tapped ...such Auto-transformers are a menace. and banned in Australia...but who knows what migrants bring here then flog later. Working on mains-operated sets, particularly valve setsshold be done with insulating footwear, a rubber mat and long sleeves...the sad part is that even protected from an earth conductivity that way, contacting low voltage (110-1000V) usually is with the other hand or arm to chassis and whether 'mains' earthed or B+ negative you will become a part of the circuit.
In closing...wallops from charged electrolytics are not microsecond experiences. They can do serious damage, even kill. Do NOT discharge them using a short to chasis...that begins to destroy the capacitor. Place a high value, adequate resistor..e.g. 20k or so across the cap (use say 5W) and nevertheless...check voltage as a matter of high-awareness/precautionary , self-respecting habit. Check that resistor from time to time also...it may fail or substantially change value.
Never work on a set 'turned-on' if possible to not do so. Pull the plug from the mains supply..not just turn off the set. Work mindfully. Try not to work alone, or at least advise family of what you are doing and leave your door open so they can check on you unobtrusively and hear you scream if' hooked-up' or getting an electrolytic discharge.. and you WILL scream.
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Hi Jan...thanks for the support and kind comment...much appreciated. I made some further corrections and additions to my post and then was told I'd exceeded 30 minutes...I wish I'd known the limitation before-hand.
I've had several narrow escapes from death and my recent 'Masters' was "OHS and Environment Management" with additional subjects on the psychology of risk. None of that covered electricals...that's my own expertise.
I started out as an apprentice electrical fitter-mechanic...a high level course which included building a 3 ph. 'wave-wound' motor from 'scratch'...hand filing all the commutator segments from rough copper bar to as I recall 17.5 degrees highly polished taper, winding all the coils and building all its mica and commutator locking device using lathe. Today in Qld any electrical 'mechanic' can call himself a 'fitter-mechanic'.
They haven't a clue today (chuckles) about what a fitter-mechanic 'was'or should -be but then when teaching electrical trades students for a year or two in Qld I found most don't have much of a clue 'period' and are desperately devoid of safety knowledge. On an average basis Qld is way behind NSW of say the 70's and NSW behind Victoria of the 1950's. Apprenticeships have largely become a farce and safety is the last thing on the list...which includes bosses lying to the apprenticeship 'board' and to me when I was requiring student records to enable students to do the licensing. I could go into 'alarming' detail but will not, here. There was however no formal and competent safety training other than what I have them independently. At the age of suboptimal decisions they are put into high risk situations without competent guidance at TAFE or at work. Some die...and the death of one haunts me even now, 40 years later.
Our 'capstone' team told me in the last decade that 75% of students should not be licensed...but they are to keep the 'system' going and classrooms ready for more profit. All my classes, from the outset, were double size at no more pay TAFE has become a greedy commercialised sausage machine which even with general 'serious' health issues at the college (gold coast area) took umbridge at me telling them the correct actions to take in cleanliness in toilet areas and classrooms. They were doing nothing and then presumably deliberately thwarted the cleanliness issue. There seems to be a sector which 'deep-down' resents safety methodology.
As a young feller I was apprentice lift mechanic on high rise (then to 47 stories) and suffer now from injury and abuse back then. Carrying two tool boxes up 47 stories of stairs twice a day for myself and once for my boss (for example) also did long term damage. I now also have silicosis/asbestosis which on top of other injuries is no fun. I've been working in high risk areas and on valve sets for over 60 years. I guess I can't help myself when it comes to comments on risk (chuckles!)...I dive-in and start talking.
One should always balance opportunity against risk in any theatre of operations but there's no coming back if the opportunity to succeed or profit takes your life...our most valuable commodity and opportunity .
Where's "BE' by the way (your location)..warm regards
I've had several narrow escapes from death and my recent 'Masters' was "OHS and Environment Management" with additional subjects on the psychology of risk. None of that covered electricals...that's my own expertise.
I started out as an apprentice electrical fitter-mechanic...a high level course which included building a 3 ph. 'wave-wound' motor from 'scratch'...hand filing all the commutator segments from rough copper bar to as I recall 17.5 degrees highly polished taper, winding all the coils and building all its mica and commutator locking device using lathe. Today in Qld any electrical 'mechanic' can call himself a 'fitter-mechanic'.
They haven't a clue today (chuckles) about what a fitter-mechanic 'was'or should -be but then when teaching electrical trades students for a year or two in Qld I found most don't have much of a clue 'period' and are desperately devoid of safety knowledge. On an average basis Qld is way behind NSW of say the 70's and NSW behind Victoria of the 1950's. Apprenticeships have largely become a farce and safety is the last thing on the list...which includes bosses lying to the apprenticeship 'board' and to me when I was requiring student records to enable students to do the licensing. I could go into 'alarming' detail but will not, here. There was however no formal and competent safety training other than what I have them independently. At the age of suboptimal decisions they are put into high risk situations without competent guidance at TAFE or at work. Some die...and the death of one haunts me even now, 40 years later.
Our 'capstone' team told me in the last decade that 75% of students should not be licensed...but they are to keep the 'system' going and classrooms ready for more profit. All my classes, from the outset, were double size at no more pay TAFE has become a greedy commercialised sausage machine which even with general 'serious' health issues at the college (gold coast area) took umbridge at me telling them the correct actions to take in cleanliness in toilet areas and classrooms. They were doing nothing and then presumably deliberately thwarted the cleanliness issue. There seems to be a sector which 'deep-down' resents safety methodology.
As a young feller I was apprentice lift mechanic on high rise (then to 47 stories) and suffer now from injury and abuse back then. Carrying two tool boxes up 47 stories of stairs twice a day for myself and once for my boss (for example) also did long term damage. I now also have silicosis/asbestosis which on top of other injuries is no fun. I've been working in high risk areas and on valve sets for over 60 years. I guess I can't help myself when it comes to comments on risk (chuckles!)...I dive-in and start talking.
One should always balance opportunity against risk in any theatre of operations but there's no coming back if the opportunity to succeed or profit takes your life...our most valuable commodity and opportunity .
Where's "BE' by the way (your location)..warm regards
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Amusing comment!
I note that such USA/UK equipment as cited comes with warnings that unqualified persons should not try to work on it. Those should be observed.
There's no logic in attempting to isolate such praise only to those Powers. European consumer gear has many of the same features. There are plenty of hot chassis and/or cost-down equipments from all around the globe.
The Tesla tabletop AM/Shortwave set here is not isolated by transformer. It is made for 230V and includes an option for 115V operation for export use.
While the Drake uses a 5W resistor to power a VFO, the Tesla runs on 230V by losing 115V in a 40W resistor that gets so hot it is enclosed in a perforated metal can. True classic design!
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Hi man with the funny eyes......the Americans produced more of it and are still so protective of it (chuckles) and "Mr Carson' the you-tube techo also excuses it. I haven't seen a transformer-less modern set....well for donkey's ages. I did mention the UK as an offender and also some of the Tektronix 'Dicky-Knee's" as reactionary.
During WW11 with metals in such high demand transformer-less-ness may have had an excuse but in Europe and UK voltage is 220 at mains not 220 split into 2 x110 as in USA.
In USA there seem to be defenders of the (would be) realm who refuse to believe 110v can have any adverse physical effect, let alone be fatal. I hear the cry of Tarzan ringing in my head when I read some American comments on safety (I'd probably be more affected if I could read Somali or Zulu or Afrikaaans, Indonesian Chinese or Japanese but (Deo-gratias) I'm stuck with reading French or English...and what is considered 'English' by the Gates organisation.
Tesla, Well thanks a lot!!….I have an old Tesla portable here....which I bought fully restored for a Motza decades ago. I'll have to do its caps before moving it on (at considerable loss'). You have now raised the possibility of a Zoloft milkshake if I find that has no transformer....Thanks mate!(LOL!!)
If such transformer-less sets exists all around the globe even in the days of 'doubly-insulated' I can only mourn such affairs. To rid myself of any hypocrisy...mea maxima culpa... a couple of days ago I bought a BC 348 receiver fromUSA..US mod'd by a professional organisation. To my 'horror' I saw it was transformer-less as a push-pull 2 x 6V6 amp was taking the usual transformer space where th dynamotor once 'was'. The thing is … I know I can remove the huge filter cap under-chassis and put a transformer there..or at worst use a double wound 240/11 trannie and earth the chassis. To quote Doc Holliday in that brilliantly intellectual Western "Tombstone" .."Mah hypocrisay goes only so fayar' et...Voila.
During WW11 with metals in such high demand transformer-less-ness may have had an excuse but in Europe and UK voltage is 220 at mains not 220 split into 2 x110 as in USA.
In USA there seem to be defenders of the (would be) realm who refuse to believe 110v can have any adverse physical effect, let alone be fatal. I hear the cry of Tarzan ringing in my head when I read some American comments on safety (I'd probably be more affected if I could read Somali or Zulu or Afrikaaans, Indonesian Chinese or Japanese but (Deo-gratias) I'm stuck with reading French or English...and what is considered 'English' by the Gates organisation.
Tesla, Well thanks a lot!!….I have an old Tesla portable here....which I bought fully restored for a Motza decades ago. I'll have to do its caps before moving it on (at considerable loss'). You have now raised the possibility of a Zoloft milkshake if I find that has no transformer....Thanks mate!(LOL!!)
If such transformer-less sets exists all around the globe even in the days of 'doubly-insulated' I can only mourn such affairs. To rid myself of any hypocrisy...mea maxima culpa... a couple of days ago I bought a BC 348 receiver fromUSA..US mod'd by a professional organisation. To my 'horror' I saw it was transformer-less as a push-pull 2 x 6V6 amp was taking the usual transformer space where th dynamotor once 'was'. The thing is … I know I can remove the huge filter cap under-chassis and put a transformer there..or at worst use a double wound 240/11 trannie and earth the chassis. To quote Doc Holliday in that brilliantly intellectual Western "Tombstone" .."Mah hypocrisay goes only so fayar' et...Voila.
I would agree that there are many, many devout collectors of those so-called AC-DC sets with no transformers and they have shelves full of them, most working.
I didn not mean to say the radios still are made around the globe, only they they were made in the past. I think they only exist as antiques.
It was not a good idea to base safety regulations on competition and greed, but what's done is done. After WWII there were still too many manufacturers and it was cut-throat. Small TV sets and radios and record players were made without mains transformers through the 1960s, and many TV sets continued to be made that way but now with 'hot' and 'cold' sides, until flat screens, that is, until PFCs and isolated switching power supplies became practical.
The advent of high voltage transistors only made it possible to build cheap childrens' phonographs without transformers. I had one of these and took it apart only to be disappointed at finding no 50C5 but a large-ish round transistor pressed into an aluminum plate.
I think the real cutoff for transformerless audio stuff was when the power was more than about 10 Watts out, and for TV sets, when they were too large for a voltage doubler, but after that the solid state ones used to be hot all the way to the flyback transformer primary. The flyback circuit becoming more well-regulated evolved to become the power transformer and the several auxiliary windings on it were isolated and powered the low voltage transistor and IC circuits.
During that transition a lot of the TV repair men had a steep learning curve since they now had two things to deal with in one circuit: the regulated B+ so to speak and the regulated high voltage for the CRT. I used to repair the RCA brand and if there was any fault, the thing would sit there and make a ticking sound from the HV supply IIRC there was an SCR and a HV transistor involved. It was not hard to diagnose but there were procedures written by RCA to do it quickly and those who had not kept up with technology were frustrated beyond measure.
In the antique radio club we discuss the hazards of transformerless sets and how to fix that. Some of the serious collectors use an isolation transformer to power everything thay have displayed on their shelves. There was for a long time in this country the non-polarized plug, which gave people a tickle if inserted so the B- to chassis capacitor was on the hot side of the line. If they were in the bathroom, the tickle was more than a tickle.
I don't know who "Tektronix 'Dicky-Knee's" are.
I dismiss the Tarzan types. If they want to be careless about 120V then it is their funeral. They simply have not been introduced intimately enough to it to get the point.
I just took the Tesla off the shelf (I have no real collection, just 4 or 5 of the transformerless radios and a battery set from the old days when I was in the repair business) and thought I'd plug it in.. but the power cord is too decayed. I didn't replace it when I refurbished the set but it was usable, just not in good shape. It's the Talisman model and much like the so called AA5. A friend from the Czech republic sent it to me in the 1980s along with a TV set, the first Tesla model. The TV set had a very large transformer, but it was a real power hog for something with a 10" monochrome CRT.
I didn not mean to say the radios still are made around the globe, only they they were made in the past. I think they only exist as antiques.
It was not a good idea to base safety regulations on competition and greed, but what's done is done. After WWII there were still too many manufacturers and it was cut-throat. Small TV sets and radios and record players were made without mains transformers through the 1960s, and many TV sets continued to be made that way but now with 'hot' and 'cold' sides, until flat screens, that is, until PFCs and isolated switching power supplies became practical.
The advent of high voltage transistors only made it possible to build cheap childrens' phonographs without transformers. I had one of these and took it apart only to be disappointed at finding no 50C5 but a large-ish round transistor pressed into an aluminum plate.
I think the real cutoff for transformerless audio stuff was when the power was more than about 10 Watts out, and for TV sets, when they were too large for a voltage doubler, but after that the solid state ones used to be hot all the way to the flyback transformer primary. The flyback circuit becoming more well-regulated evolved to become the power transformer and the several auxiliary windings on it were isolated and powered the low voltage transistor and IC circuits.
During that transition a lot of the TV repair men had a steep learning curve since they now had two things to deal with in one circuit: the regulated B+ so to speak and the regulated high voltage for the CRT. I used to repair the RCA brand and if there was any fault, the thing would sit there and make a ticking sound from the HV supply IIRC there was an SCR and a HV transistor involved. It was not hard to diagnose but there were procedures written by RCA to do it quickly and those who had not kept up with technology were frustrated beyond measure.
In the antique radio club we discuss the hazards of transformerless sets and how to fix that. Some of the serious collectors use an isolation transformer to power everything thay have displayed on their shelves. There was for a long time in this country the non-polarized plug, which gave people a tickle if inserted so the B- to chassis capacitor was on the hot side of the line. If they were in the bathroom, the tickle was more than a tickle.
I don't know who "Tektronix 'Dicky-Knee's" are.
I dismiss the Tarzan types. If they want to be careless about 120V then it is their funeral. They simply have not been introduced intimately enough to it to get the point.
I just took the Tesla off the shelf (I have no real collection, just 4 or 5 of the transformerless radios and a battery set from the old days when I was in the repair business) and thought I'd plug it in.. but the power cord is too decayed. I didn't replace it when I refurbished the set but it was usable, just not in good shape. It's the Talisman model and much like the so called AA5. A friend from the Czech republic sent it to me in the 1980s along with a TV set, the first Tesla model. The TV set had a very large transformer, but it was a real power hog for something with a 10" monochrome CRT.
I know is odd, I didn't know if it was already mentioned...but first safe measure you can take dealing with high voltage is to be sure you are into stable position and there are not risk to fall in a dangerous way. I was witness at accidents with guys falling from mobile stairs and broked bones and guys shocked working on a border of top of the roof. It just happen he was projected in front and not in back saving him from a falling from tens of m height. Domestic shock muscle contraction projection by arcing can be also fatal, it well depend where you.ll be thrown...
Sy Said: Quote: When you decide to work on high voltage circuits, spend time around e
Too true, ....many years ago when I was an expert in switch mode, I got stung by the very blighter I had repaired...a high power resonant converter which was part of an ionised metal-on-plastic plating coating system. One respects this as the static and corona produced was particularly high but I should have known better. Under such conditions, the company had a policy of the 'dead man's pedal', that is to activate the bench supply one had to keep one's foot on the pedal switch that with any immediate shock the whole body convulses, resulting with the foot reflex to open the foot pedal switch, aka sim to sewing machine pedal, even though the switch maybe not directly related to actual equipment under testing. Just as important it clears the tricky area of anyone coming to the rescue without suffering the same fate.
Similar for train drivers (and steam which I am) where constant acknowledging of the warning button within a certain time window otherwise the Breaks come on with all the consequences.
On the bench, apart from mains isolating transformers, it is imperative to have a low current earth trip as I'm not the only person to have accidentally plonked the soldering iron on the mains flex.
I have done alot in my life on tube amps, workshops and one's attitude goes a very long way in dealing with high voltage repairs. It ain't a dreamer's job, and those of us who were brought up both AC/DC TV's and radios of the 1940's-50's with the dreaded two wire 'one side of the mains connected to the chassis' will all know too well. In my days, each lab had to have a dry stick as a way someone else able to move a live body without getting stung.
Play safe and don't loose one's ticket.
rJ
Too true, ....many years ago when I was an expert in switch mode, I got stung by the very blighter I had repaired...a high power resonant converter which was part of an ionised metal-on-plastic plating coating system. One respects this as the static and corona produced was particularly high but I should have known better. Under such conditions, the company had a policy of the 'dead man's pedal', that is to activate the bench supply one had to keep one's foot on the pedal switch that with any immediate shock the whole body convulses, resulting with the foot reflex to open the foot pedal switch, aka sim to sewing machine pedal, even though the switch maybe not directly related to actual equipment under testing. Just as important it clears the tricky area of anyone coming to the rescue without suffering the same fate.
Similar for train drivers (and steam which I am) where constant acknowledging of the warning button within a certain time window otherwise the Breaks come on with all the consequences.
On the bench, apart from mains isolating transformers, it is imperative to have a low current earth trip as I'm not the only person to have accidentally plonked the soldering iron on the mains flex.
I have done alot in my life on tube amps, workshops and one's attitude goes a very long way in dealing with high voltage repairs. It ain't a dreamer's job, and those of us who were brought up both AC/DC TV's and radios of the 1940's-50's with the dreaded two wire 'one side of the mains connected to the chassis' will all know too well. In my days, each lab had to have a dry stick as a way someone else able to move a live body without getting stung.
Play safe and don't loose one's ticket.
rJ
There's been sensible and interesting advice from contributors here unlike the Tektronix group which largely comprised of highly trained and experienced engineers I found from its owner down committed to a range from disingenuousness, partiality and pathology to character assassination on other members and chest beating promenading of ignorance on safety. DIY, its contributors living in the real and safety connected world has found instead, intelligent contributions to safety .In terms of standards high voltage is >1000volts with 'medium' a common-place next down then to low and extra low voltage. I likes the recent contribution advising people survey their environmental situation for possible further damage if muscularly freed from the connection. My experiences were as a youngster, turning on an aluminium cased drill in which the brushes had become loose (later found). I was fortunate that the lead pulled from the socket by my reaction. Later as a tradesman aged 19 I worked
for the County Council (Electrical) where we were, some 6 months later, examined on competency in lowering from pole-tops a person electrocuted or suffering high voltage shock in an earth situation. Some ended up hanging the dummy, others saw it just drop to the ground. It's wrong to assume people you work-with, or for, are more interested in your safety than their objectives. … A year or so later working in an industrial concern I worked on a sub-board whilst jammed in between metal lockers and a switchboard. I'd turned off the main switch and fitted a warning tag which should not be removed without my signature. I worked as always on a dead board as though live, at which I'd become pretty skilled. Completed, I returned to remove the tag, to my alarm finding it already removed and the switch 'on'. I yelled 'which of you ^%$#@*^'s turned this switch on. One boiler maker....too big even for me to take on ...said "I did" After dressing him down I said 'why....why did you do it??" 'I wanted to use the circuit' (controlled by the switchboard) he said, without any sense of 'sorry'.. That's the sort of idiot one experiences from time to time. Since then different breaker types, RCD's and positive lockouts have been created, even for the Westinghouse breakers which are of a very old design.
Some twenty years later, to give an idea of how easy it is to be 'hooked-up'. You don't need to grip a live wire to 'cop it'.Working (alone) in a set of factory offices with an aluminium cased drilling machine. By this time I was pretty adept and made a not careless so much as stupid 'not risk-assessed' move. I'd removed a light-switch to drill another hole in the architrave. With my fingertip I moved the single gang miniature switch aside. Suddenly I was hooked-up. The current was passing across my chest but I
could still think clearly. I thought of possible solutions and in this case recalling back 30 years to the factory hook-up....that the lead was too long to be pulled out. I realised I was yelling.How long hooked-up?...felt like a minute, might have been 20 seconds Suddenly I 'flew' backwards into the partition wall and heard the loud bang...… Recovering but with a very sore hand and fingertip on their way I went to the person working two offices away...whom I had known for a couple of years … "didn't you hear me yelling"...'yes'....Did you hear me crash into the wall?"...'Yes' "Well....why didn't you investigate?"...he just shrugged and went on writing. On that and other experiences, don't expect others to immediately act on 'what's happening" and save perhaps your life. Your contributor was spot on, I could have been in a location where being 'spasmed' backwards could have made serious injury or death. Always, as should for example tree-fellers...look around and plan for safety. Now a graduate in Masters in OHSEM at 'over 70; I've a great awareness of unsafe situations from marine, agriculture, construction sites and other exposures. Safety has to become assimilated from instinct and preparation...look for secondary and tertiary outcomes if 'something went wrong'. In valve radio work...and I copped a whopper recently...discharging electro-caps to earth can damage them...better them than you...but look to providing a discharge path...soldering or even clipping say 10k across the electro whilst working on the set. It RCD is not on the breaker board, test before sing it, a portable RCD unit Sometimes even if the unit is good the earthing is not!...Supervising an Australian construction site in Vietnam...and the site and contractor refused to fix it...was an RCD covering all the site (thus 100mA and likely useless)..but no earth connected to the main switchboard board. Your hair would stand on end if you saw my photos of the switchboard and wiring. The contractor interrupted with a demand, the job being 'fast tracked' with a cannot be lengthened' completion date that I desist my protocol of earthing every steel wall in case say a wire came loose from a GPO and contacted the wall. I refused but he had the ultimate 'say' on all matters and the workers bowed to his commands. I did go further but will leave it there. Someone may one day die from a job I supervised and that has troubled me for a decade. Moral?...be alert, very different from paranoia, all the time. Don't rely on others to have covered all safety bases. Quoting catalin gramada's wisdom. ' first safe measure you can take dealing with high voltage is to be sure you are into stable position and there are not risk to fall in a dangerous way."
The great gap between wellful/healthy and 'wellbeing' is one even the Uni doesn't quite 'get'. Wellbeing is a state of virtuousness...very different, in fact the opposite of 'sanctimoniousness',which is in fact a very troubled state.
Wellbeing is a state of developed yet, paradoxically, always maturing heightened awareness in which untroubled by problems and distractions playing on his/her mind a person works in an assimilated frame of complete mindfulness and situational awareness.
Assimilation has occurred when we no longer do things consciously. The 'change' has become a part of us. We can change and work on consciously changing but during change we are vulnerable. When one day a person realises they have not thought about or taken action about a personal problem but are doing it as a matter of course, they may have assimilated the goal. If they then reflect on it the assimilation is not completed. I can give examples but have already made a long dissertation.
In closing...I recently had disconnected an external power supply from a communications receiver. The socket from the supply was protected by a metal shroud...you'd know the type. The supply was turned-off. I held the set whilst blindly reinstalling the plug...I did not realise the metal shroud (which usually never contacted the chassis directly when installed) was contacting the B+ and I became the discharge path for the electrolytic...WooooW!!...that was quite a belt!...I later checked the, cap....still charged... charge voltage...nearly 350 volts. Great with the theory I'd not taken into account a 'tiny' mishap which, had it continued could have killed me or given me other damage had I say fallen or hit my head on the bench. Only skin resistance save us from low voltage electrocution and when sweating salty perspiration...as climate change continues soaring temperatures in extended summers.... that protection is reduced.
To quote 'richwalters wisdom' …."high voltage repairs. It ain't a dreamer's job"
for the County Council (Electrical) where we were, some 6 months later, examined on competency in lowering from pole-tops a person electrocuted or suffering high voltage shock in an earth situation. Some ended up hanging the dummy, others saw it just drop to the ground. It's wrong to assume people you work-with, or for, are more interested in your safety than their objectives. … A year or so later working in an industrial concern I worked on a sub-board whilst jammed in between metal lockers and a switchboard. I'd turned off the main switch and fitted a warning tag which should not be removed without my signature. I worked as always on a dead board as though live, at which I'd become pretty skilled. Completed, I returned to remove the tag, to my alarm finding it already removed and the switch 'on'. I yelled 'which of you ^%$#@*^'s turned this switch on. One boiler maker....too big even for me to take on ...said "I did" After dressing him down I said 'why....why did you do it??" 'I wanted to use the circuit' (controlled by the switchboard) he said, without any sense of 'sorry'.. That's the sort of idiot one experiences from time to time. Since then different breaker types, RCD's and positive lockouts have been created, even for the Westinghouse breakers which are of a very old design.
Some twenty years later, to give an idea of how easy it is to be 'hooked-up'. You don't need to grip a live wire to 'cop it'.Working (alone) in a set of factory offices with an aluminium cased drilling machine. By this time I was pretty adept and made a not careless so much as stupid 'not risk-assessed' move. I'd removed a light-switch to drill another hole in the architrave. With my fingertip I moved the single gang miniature switch aside. Suddenly I was hooked-up. The current was passing across my chest but I
could still think clearly. I thought of possible solutions and in this case recalling back 30 years to the factory hook-up....that the lead was too long to be pulled out. I realised I was yelling.How long hooked-up?...felt like a minute, might have been 20 seconds Suddenly I 'flew' backwards into the partition wall and heard the loud bang...… Recovering but with a very sore hand and fingertip on their way I went to the person working two offices away...whom I had known for a couple of years … "didn't you hear me yelling"...'yes'....Did you hear me crash into the wall?"...'Yes' "Well....why didn't you investigate?"...he just shrugged and went on writing. On that and other experiences, don't expect others to immediately act on 'what's happening" and save perhaps your life. Your contributor was spot on, I could have been in a location where being 'spasmed' backwards could have made serious injury or death. Always, as should for example tree-fellers...look around and plan for safety. Now a graduate in Masters in OHSEM at 'over 70; I've a great awareness of unsafe situations from marine, agriculture, construction sites and other exposures. Safety has to become assimilated from instinct and preparation...look for secondary and tertiary outcomes if 'something went wrong'. In valve radio work...and I copped a whopper recently...discharging electro-caps to earth can damage them...better them than you...but look to providing a discharge path...soldering or even clipping say 10k across the electro whilst working on the set. It RCD is not on the breaker board, test before sing it, a portable RCD unit Sometimes even if the unit is good the earthing is not!...Supervising an Australian construction site in Vietnam...and the site and contractor refused to fix it...was an RCD covering all the site (thus 100mA and likely useless)..but no earth connected to the main switchboard board. Your hair would stand on end if you saw my photos of the switchboard and wiring. The contractor interrupted with a demand, the job being 'fast tracked' with a cannot be lengthened' completion date that I desist my protocol of earthing every steel wall in case say a wire came loose from a GPO and contacted the wall. I refused but he had the ultimate 'say' on all matters and the workers bowed to his commands. I did go further but will leave it there. Someone may one day die from a job I supervised and that has troubled me for a decade. Moral?...be alert, very different from paranoia, all the time. Don't rely on others to have covered all safety bases. Quoting catalin gramada's wisdom. ' first safe measure you can take dealing with high voltage is to be sure you are into stable position and there are not risk to fall in a dangerous way."
The great gap between wellful/healthy and 'wellbeing' is one even the Uni doesn't quite 'get'. Wellbeing is a state of virtuousness...very different, in fact the opposite of 'sanctimoniousness',which is in fact a very troubled state.
Wellbeing is a state of developed yet, paradoxically, always maturing heightened awareness in which untroubled by problems and distractions playing on his/her mind a person works in an assimilated frame of complete mindfulness and situational awareness.
Assimilation has occurred when we no longer do things consciously. The 'change' has become a part of us. We can change and work on consciously changing but during change we are vulnerable. When one day a person realises they have not thought about or taken action about a personal problem but are doing it as a matter of course, they may have assimilated the goal. If they then reflect on it the assimilation is not completed. I can give examples but have already made a long dissertation.
In closing...I recently had disconnected an external power supply from a communications receiver. The socket from the supply was protected by a metal shroud...you'd know the type. The supply was turned-off. I held the set whilst blindly reinstalling the plug...I did not realise the metal shroud (which usually never contacted the chassis directly when installed) was contacting the B+ and I became the discharge path for the electrolytic...WooooW!!...that was quite a belt!...I later checked the, cap....still charged... charge voltage...nearly 350 volts. Great with the theory I'd not taken into account a 'tiny' mishap which, had it continued could have killed me or given me other damage had I say fallen or hit my head on the bench. Only skin resistance save us from low voltage electrocution and when sweating salty perspiration...as climate change continues soaring temperatures in extended summers.... that protection is reduced.
To quote 'richwalters wisdom' …."high voltage repairs. It ain't a dreamer's job"