Mark A. Gulbrandsen said:
you can always buy a TEK camera -- if you can find the Polaroid Type 67 film -- it is available, just a bit more difficult to find. A digital camera is what I use with my HP3585A spectrum analyzer.
there was an article in Audio Amateur around 1980 called "A Timerless Tone Burst Generator" -- basically you use a pair of CMOS multiplexers used in their bipolar mode to gate an audio signal -- an opamp was used as the comparator to set the thresh-hold and a series of flip-flops were used to set the aperture. (controlling the CMOS multiplexers
Hi,
can we go back to analogue scope and some kind of tone burst generator?
Anyone know of PC software (freeware) that can generate what is needed?
Is low & Hi freq needed as well as 1kHz?
Is there a cheap way to measure the increase in distortion due to the onset of clipping (but not yet visible).
can we go back to analogue scope and some kind of tone burst generator?
Anyone know of PC software (freeware) that can generate what is needed?
Is low & Hi freq needed as well as 1kHz?
Is there a cheap way to measure the increase in distortion due to the onset of clipping (but not yet visible).
just google "toneburst freeware"
http://www.audiosignal.co.uk/freeware.html
you can measure distortion with a sound card -- just by taking the square root of the sum of the squares of the harmonic voltages and divide by the fundamental. the first couple of harmonics should be satisfactory.
http://www.audiosignal.co.uk/freeware.html
you can measure distortion with a sound card -- just by taking the square root of the sum of the squares of the harmonic voltages and divide by the fundamental. the first couple of harmonics should be satisfactory.
"Can the 7633 work as a regular Oscope? If so I can go ahead sell the 7904 I got. I see a nice 7633 on ebay and the seller claims a bright CRT for it."
I would get the storage scope first and see if the trace is good enough for you for general purpose use. Those wire mesh type crt's sometimes have a bit softer display than the normally very sharp trace you'd see on a 7904.
Mark
I would get the storage scope first and see if the trace is good enough for you for general purpose use. Those wire mesh type crt's sometimes have a bit softer display than the normally very sharp trace you'd see on a 7904.
Mark
Fresh in from my restoration bench is a Tektronix 214 which is probably the worlds smallest ever CRT absed storage scope, dual trace 500 khz bandwidth. I got this one off E-Bay for about $60.00. The seller sent me the wrong scope(should have been a plain old TEK 212) and never replied to my e-mails so I just kept it and decided to restore it. The scope was dead and with bad ni-cads these scopes will not fuinction at all because the batteries are used as a shunt regulator of sorts. Things went a bit haywire after I installed the new batteries.... an 100uf Tantlum cap shorted and also burned up the main 12 volt DC buss traces from the batteries to the on-off switch. Good proof that Tantlum caps do not like to sit around for years without being kept formed.
After those repairs were made the boards, case parts, knobs, and other parts were cleaned and the switch contacts, header connections between boards, and controls were treated with Caig Labs De-Oxide. The scope was then checked for calibration and found to be so close that any forther calibration was really un-necessary. A good testiment to the build quality of Tektronix products!!
After those repairs were made the boards, case parts, knobs, and other parts were cleaned and the switch contacts, header connections between boards, and controls were treated with Caig Labs De-Oxide. The scope was then checked for calibration and found to be so close that any forther calibration was really un-necessary. A good testiment to the build quality of Tektronix products!!
Attachments
Here are the insides of the scope with the top pcb folded back out of the way. That top pcb is the horiz and vert. deflection amp and the CRT geometry adj. circuitry. The ni-cad packs are see on both sides of the crt neck. A full charge of the ni-cads gives about 3 hours of operation.
Attachments
This is miniaturization circa the mid 1970's! Pretty advanced even for today...... custom IC's are prevelent in most Tektronix products. Note that ALL semiconductors are in sockets! This supposedly allowed TEK to meet specs more consistantly which I definately agree with sonce most of their products always seem to exceed the specs by at least 30% of the ratings.
Attachments
The 3" diaganol storage CRT with internally etched graticle. This is a flood gun type storage crt and there are actually two electron guns in the neck. The base is about the size of a nickle and the long black cable connects to other elements in the crt that are up near the screen and used for the storage mode. Note the full mu-metal shield.
Attachments
It all fits neatly but barely into the plastic case. The test leads and AC cord wind around a storage pod on the back of the scope. It all weighs just 3 lbs. In my opinion this scope is still far ahead of the cheap LCD scopes that are being sold today. Certainly a bargain at $60.00 and another $15.00 for new ni-cads.
Mark
Mark
Attachments
"I would never have thought the tants would blow like that."
I've seen many tants short over the years but not generally like this one. Its rare to see one this large though. Of course that black pinhole was hidden under the inverter transistor as the transistor was bent down over that cap! With the new batteries installed the scope ran for about 5 min and then a mushroom cloud formed over the unit...... Of cource the cap was right across the full output of the ni-cads and the traces between it and the ni-cads acted like a fuse... and to make matters worse this is a three layer board with the DC buss traces in the center layer. They became so vaporized that they were no longer even there. Two jumper wires on the back of the board took care of it as well as a new 100 uf cap. The two film caps couple the bridge rectifier to the AC line... no transformer in this unit. The 12 volt DC then feeds a power inverter system that generates all the necessary DC low and high operating voltages..... about 7 different voltages ranging from 5 volts to -1000.
Mark
I've seen many tants short over the years but not generally like this one. Its rare to see one this large though. Of course that black pinhole was hidden under the inverter transistor as the transistor was bent down over that cap! With the new batteries installed the scope ran for about 5 min and then a mushroom cloud formed over the unit...... Of cource the cap was right across the full output of the ni-cads and the traces between it and the ni-cads acted like a fuse... and to make matters worse this is a three layer board with the DC buss traces in the center layer. They became so vaporized that they were no longer even there. Two jumper wires on the back of the board took care of it as well as a new 100 uf cap. The two film caps couple the bridge rectifier to the AC line... no transformer in this unit. The 12 volt DC then feeds a power inverter system that generates all the necessary DC low and high operating voltages..... about 7 different voltages ranging from 5 volts to -1000.
Mark
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.