well, i dug up 16 MUR1520's.
i desoldered the 1N4005's, and sure enough, half were 0 resistance on one board. so, they were shorting out the circuit. im going to replace all of them with the MUR1520's and hopefully that will work!
i already tested all the MUR's and they all work ok with the diode tester, so they should be ok. i have to repair the traces though too
, but that wont be too hard.
i desoldered the 1N4005's, and sure enough, half were 0 resistance on one board. so, they were shorting out the circuit. im going to replace all of them with the MUR1520's and hopefully that will work!
i already tested all the MUR's and they all work ok with the diode tester, so they should be ok. i have to repair the traces though too
, but that wont be too hard.
sigh. 
i replaced all the 1N4005's with MUR1520's and still the same problem. however, thanks to the light bulb suggestion, no more destroyed boards and diodes.
i have all the secondaries and primaries from the transformer routing through a euro style connecting block. i have triple-checked it, and it doesnt seem to be the problem. when i take the PSU boards away and just hook up the transformer (with the connecting block), everything works fine and i get the voltages i should be getting. i turn it on, get the right voltage, the LED lights up on the connecting block, and the light bulb is off.
as soon as i wire in the PSU board (just one of them), i turn it on, and a get a nice bright light bulb. very sad. i have tested all the resistors and diodes in circuit, and all seem to be ok. i dont really have a way to test the transistors, could they be causing a short? i also tested the caps, and they test great too.
any ideas? i even used nylon parts to mount the board in the case, just in case i was getting a short from the standoffs (which i wasnt). this is really really confusing. i can take pics of the setup if needed.
i replaced all the 1N4005's with MUR1520's and still the same problem. however, thanks to the light bulb suggestion, no more destroyed boards and diodes.
i have all the secondaries and primaries from the transformer routing through a euro style connecting block. i have triple-checked it, and it doesnt seem to be the problem. when i take the PSU boards away and just hook up the transformer (with the connecting block), everything works fine and i get the voltages i should be getting. i turn it on, get the right voltage, the LED lights up on the connecting block, and the light bulb is off.
as soon as i wire in the PSU board (just one of them), i turn it on, and a get a nice bright light bulb. very sad. i have tested all the resistors and diodes in circuit, and all seem to be ok. i dont really have a way to test the transistors, could they be causing a short? i also tested the caps, and they test great too.
any ideas? i even used nylon parts to mount the board in the case, just in case i was getting a short from the standoffs (which i wasnt). this is really really confusing. i can take pics of the setup if needed.
hum, well, i checked ALL the zeners, the resistors and replaced the fets with new ones.
it doesnt light the light bulb anymore, it actually runs! but, i am only getting -60. on the + side, its only giving me like 8v or something. so maybe the 9610 died? ugh, this is so annoying because it all worked just fine before i started putting it all in the case.
it doesnt light the light bulb anymore, it actually runs! but, i am only getting -60. on the + side, its only giving me like 8v or something. so maybe the 9610 died? ugh, this is so annoying because it all worked just fine before i started putting it all in the case.
Banned
Joined 2002
well, unfortunately i dont own a variac
im actually not THAT frustrated quite yet. i have made some progress, and i suspect its the fets. i had the boards just sitting out for a month or so on a shelf, so there was a good chance they could have shorted out or something. and im not 100% sure the replacement fets i had are good either. i need to sit down and test all the fets i have to make sure they all work ok. i did notice a few bad zeners too. its just a LOT of things going wrong with those boards...
im almost tempted to just completely repopulate them (minus those MUR1520's though).
im actually not THAT frustrated quite yet. i have made some progress, and i suspect its the fets. i had the boards just sitting out for a month or so on a shelf, so there was a good chance they could have shorted out or something. and im not 100% sure the replacement fets i had are good either. i need to sit down and test all the fets i have to make sure they all work ok. i did notice a few bad zeners too. its just a LOT of things going wrong with those boards...
im almost tempted to just completely repopulate them (minus those MUR1520's though).
Maybe it's time to invest in an antistatic mat with the wriststrap.
http://www.electroflash.org.nz/products/products1j.htm#Antistatic
http://www.electroflash.org.nz/products/products1j.htm#Antistatic
Banned
Joined 2002
kilowattski,
i have one. i dont think i had one when the PSU boards were first built though... i do have one now though.
jleaman,
last time i checked, a variac wasnt exactly cheap. not terribly expensive, but not cheap. and its not something ive found surplus either.
how exactly would a variac help me out here though? with the light bulb thingie i dont seem to be blowing anything anymore. ive heard that a variac is a good thing to have, and i know what they do, but im just not sure what exactly their benefit is...
edit:
thanks for the compliments though
i have one. i dont think i had one when the PSU boards were first built though... i do have one now though.
jleaman,
last time i checked, a variac wasnt exactly cheap. not terribly expensive, but not cheap. and its not something ive found surplus either.
how exactly would a variac help me out here though? with the light bulb thingie i dont seem to be blowing anything anymore. ive heard that a variac is a good thing to have, and i know what they do, but im just not sure what exactly their benefit is...
edit:
thanks for the compliments though
Banned
Joined 2002
i bought a ceramic light bulb base and a pack of lightbulbs for like $4.
i chopped two power cords and spliced them all togehter. now i have a power cord with a light bulb in series with it, so i can plug in anything and test for shorts. it works very well.
although, it doesnt tell me what exactly is going wrong. if there was a little tip that could do that, i would be all over it!
i think i might just buy all new 610's and 9610's. they are pretty cheap and i have a few things i need to buy from digikey anyways... ugh.
i chopped two power cords and spliced them all togehter. now i have a power cord with a light bulb in series with it, so i can plug in anything and test for shorts. it works very well.
although, it doesnt tell me what exactly is going wrong. if there was a little tip that could do that, i would be all over it!
i think i might just buy all new 610's and 9610's. they are pretty cheap and i have a few things i need to buy from digikey anyways... ugh.
i didnt want to start a new thread, so ill just continue this one...
after getting very frustrated and messing with this thing for days, i couldnt find anyting wrong with it. i individually metered each part and everything tested just fine. so, as a last straw before i rebuilt the whole thing, i just hooked it up again. it worked. i tried the other one, it worked. i tried both, they both work. i stopped thinking about it and just went on working
i have NO clue what happened, but it works like a champ now. i have it on and off all the time to test and measure, and its never given me a problem, and the PSU is mounted in there for good now:
http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp10.jpg
i also took extra caution to shield things and keep the transformer as far away from the preamp circuit as possible. unfortunately, its a small case to fit an 800va transformer and all the other junk in, so i was limited. but i just ended up doing a "firewall" in between the preamp and power supply section (cold-rolled steel) and also putting a piece of steel around the transformer itself for further sheilding. i learned my lesson with my aleph3's.
http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp11.jpg
so its getting close to done. thanks to a donation from Synergistic Research cable, i have some decent wire to hook up the signal path with. they have been following my projects for awhile and like what i do, so they donated some alpha sterling hookup wire.
i basically just have to hook up the volume control and its pretty much done! here are two more pics of the front panel. its just a mock-up, so things will be different in the end. the shafts for the knobs are too long right now, so the knobs stick out way too far in my opinion. they stick out 1" now, i want them to be about 0.25". that will look nice and clean.
the wood front panel is a mirror reflection in the right light and without patterns in front of it (little jab to bill). the lights could be brighter, but would look awesome at night in a dim room.
http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp12.jpg
http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp13.jpg
this is going to be one sexy sexy preamp. i dont brag much, but im really proud of this one.
after getting very frustrated and messing with this thing for days, i couldnt find anyting wrong with it. i individually metered each part and everything tested just fine. so, as a last straw before i rebuilt the whole thing, i just hooked it up again. it worked. i tried the other one, it worked. i tried both, they both work. i stopped thinking about it and just went on working
i have NO clue what happened, but it works like a champ now. i have it on and off all the time to test and measure, and its never given me a problem, and the PSU is mounted in there for good now:
http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp10.jpg
i also took extra caution to shield things and keep the transformer as far away from the preamp circuit as possible. unfortunately, its a small case to fit an 800va transformer and all the other junk in, so i was limited. but i just ended up doing a "firewall" in between the preamp and power supply section (cold-rolled steel) and also putting a piece of steel around the transformer itself for further sheilding. i learned my lesson with my aleph3's.
http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp11.jpg
so its getting close to done. thanks to a donation from Synergistic Research cable, i have some decent wire to hook up the signal path with. they have been following my projects for awhile and like what i do, so they donated some alpha sterling hookup wire.
i basically just have to hook up the volume control and its pretty much done! here are two more pics of the front panel. its just a mock-up, so things will be different in the end. the shafts for the knobs are too long right now, so the knobs stick out way too far in my opinion. they stick out 1" now, i want them to be about 0.25". that will look nice and clean.
the wood front panel is a mirror reflection in the right light and without patterns in front of it (little jab to bill). the lights could be brighter, but would look awesome at night in a dim room.
http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp12.jpg
http://www.cowanrg.mesanetworks.net/projects/images/bosoz/preamp13.jpg
this is going to be one sexy sexy preamp. i dont brag much, but im really proud of this one.
thanks. i hope someone would notice the input selector. its a grayhill rotary that im using for input selection and LED selection.
its also the on/off switch. you can see the gears and the spring. right behind the shaft there is a DPDT switch that turns the unit on and off when the left knob is pressed in. this keeps the front panel free of awkward looking on/off switches.
that is the 4th version of that. the first version was the concept switch and it had the rotary switch enclosed in a track inside a small project box and the whole assembly slid inside the box and activated the switch. it was VERY complex and hell to wire.
this is by far the most elegant of all the designs i had. it works very well and is bullet-proof. its easy to adjust the push strength with just the one set screw on the collar. in addition, it helps align the shaft with the more tension you add. i used end mill bits to cut the holes so they are actually quite smooth and there isnt much friction. a little WD-40 makes it work just fine.
its also the on/off switch. you can see the gears and the spring. right behind the shaft there is a DPDT switch that turns the unit on and off when the left knob is pressed in. this keeps the front panel free of awkward looking on/off switches.
that is the 4th version of that. the first version was the concept switch and it had the rotary switch enclosed in a track inside a small project box and the whole assembly slid inside the box and activated the switch. it was VERY complex and hell to wire.
this is by far the most elegant of all the designs i had. it works very well and is bullet-proof. its easy to adjust the push strength with just the one set screw on the collar. in addition, it helps align the shaft with the more tension you add. i used end mill bits to cut the holes so they are actually quite smooth and there isnt much friction. a little WD-40 makes it work just fine.
the thing i like most about the faceplate is in lower light (aka, when light is not directly shining on it from flash or sunlight), you cannot even see the lights when its off. it just looks like a solid faceplate. and when it turns on, the lights just seem to come from nowhere. its exactly what i was looking for. simplicity.
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