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WIGGLING 'LITE' IN GUEST MODE

Oh no. Did I fry my system?
MUFF WIGGLER Forum Index -> 5U Format Modules Goto page 1, 2  Next [all]
Author Oh no. Did I fry my system?
Scot Solida
Tonight when plugging in a module, I accidentally shorted one of the power pins of my Dotcom system to another pin. Ever since, my Q-960 has been running constantly, the envelope generators are lit up (though they are receiving no triggers) and my oscs are dead in the water. What did I do? I really hope I didn't just screw the whole section!
Muff Wiggler
did you turn it all off, then check to make sure all power connectors are lined up properly, then power it back on?

if you mis-align the pins, all that SHOULD happen is that voltage goes to ground (ie. a misaligned connector will end up placing a power rail on a ground pin, and the power just safely dumps to ground).

I have done this before, and once you power down, make sure the connectors are aligned, and power back up, you are fine.

I can't say for sure but would think it very unlikely that you damaged anything.
Muff Wiggler
however, if you totally reversed a connector, the ground lines would still be ground and the power rails still going to modules, unable to safely dump the current to ground. The result would be applying negative voltage to an input expecting positive voltage, and vise versa (positive voltage into an input that expects negative). In this case, unless the modules all have reverse-polarity protection on the inlet (all Blacets do, many/most others do not), there is a chance you have cooked some stuff, probably just IC chips that hopefully are in sockets and can be easily replaced.
JohnLRice
Scot,

If you don't have a digital multimeter you should buy one ASAP (only $15 bucks and up and they can be found at Radio Shack, Best Buy, Home Depot, Lowes and even Target, Walmart, Fred Meyer etc)

Use the meter to check the voltages on your power rails. if one or more are not what they should be then unplg ALL your modules. If the power supply still reads bad then the power supply is damaged so fix or replace that. If the power supply is good with all modules unplugged then maybe a module or several got damaged. Plug in each module by itself and recheck the power rails until you find all of the 'bad' ones.

Best of luck!
Scot Solida
Thanks guys. Yep, still problematic after restarting. The -15 LEDs on the Q-103/101 are not lighting. I tested two of the modules that were not working with another power supply and it worked okay, so I am thinking this is a power supply thing.

Really? I need to unplug all of the modules? Removing the power supply/distributor or unplugging the harnesses won't do the trick?
Scot Solida
Oh wait. I see what you are saying. Unplug 'em all and test them one by one. Got it. This is going to take a while... I got a lotta modules on that supply (go figure, it was the big power supply powering five rows (with the exception of a few Blacet things). Ugh. Not a good night.
JohnLRice
Well, yes first off just disconnect all the harnesses from the supply and check the voltages to start.

If the power still is bad with no modules connected than just fix the power supply to start. If the power is good with no modules connected than one or MORE modules may be bad and it will really save you a lot of time to determine ALL of the modules that are bad up front.

While the process of elimination can be tedious, it is your friend! thumbs up
TrashWaveform
Welcome to one midwest wiggler from another. You mention you have a lot of modules on one supply. I could understanding some modules not receiving enough power. Get a multimeter and find out. You might want to power 5 rows with multiple power supplies to avoid the risk of power drops and ensure system stability.
Scot Solida
Hi TrashWaveform, and thanks. Yeah, there are a lot of modules on this supply... but the problem persists even if I unplug the top three rows, leaving only the two middle rows and this supply (QPS3) can supply way more than that. Something has gone terribly wrong here. I e-mailed Roger Arrick and he responded with a question that suggests that he might know what has happened. I sent him a response but have yet to hear back from him. I have my fingers (and apparently my wires) crossed. I am about to test the voltages on the supply... eek.
Scot Solida
John: what should I be testing on the power supply? There is a five-hole jack that plugs into the power harness. IS that what I should check? What readings should I expect? I assume +/- 15 V and 5 V? (that aint anything like what I am getting by the way)
Scot Solida
Muff Wiggler wrote:
however, if you totally reversed a connector, the ground lines would still be ground and the power rails still going to modules, unable to safely dump the current to ground. The result would be applying negative voltage to an input expecting positive voltage, and vise versa (positive voltage into an input that expects negative).


Muff: if this turns out to be the case, how can I right it again? Will this wayward power still be running around the system after I unplug all of the modules?
Muff Wiggler
Scot Solida wrote:
Will this wayward power still be running around the system after I unplug all of the modules?


Nope, as soon as you disconnect the power, it will be gone. If you power back up and the reversed connection is still there, it may cause more damage, so make sure all connections are proper before powering up again. If you power up and everything is connected properly, there will be no wayward current anywhere. However, the brief application of reversed power may have damaged one or more modules.

Scot Solida wrote:
if this turns out to be the case, how can I right it again?


You'll have to determine which module(s) have been damaged by the "plugging them in one at a time" method.

When you have figured out which ones are damaged, look closely on the board, in particular around the power inlet, for any visibly fried componentry... blown out diodes, etc.

If everything looks ok, I would email the manufacturer and say that I had accidentally applied reverse current, and ask what components would be likely to fry. Most likely they will identify some of the IC chips. Start by replacing these chips. Most ICs are very cheap to order replacements, like 30-cents cheap. If they are in sockets they are easy to swap the old ones out and put the replacements in.

if the module is still not working after replacing the IC chips, for me personally at that point it is beyond my own limited ability to trace/troubleshoot/fix and I would again contact the manufacturer, asking if I could send the module in for repair.
Scot Solida
Thanks Muff. Like I said, I e-mailed Roger Arrick and his question to me suggested that he had some clue, but he hasn't got back to me since my reply (he asked if all of the LEDs, +15, -15 and 5v were glowing on the Q-101 Power Control module... the -15 is not lit).

I unplugged all of the modules (well, I unplugged the harness from the supply) and re-plugged it. It still is screwy. I don't want to plug it in again, in case I might fry something else. I think I will try plugging the top three rows into the bottom row (different supply) if I can to see if they work okay. I'd hate to think that I Homer'ed my Q-960 or STG sequencers.

As you can imagine, I am a nervous wreck this evening... seriously, i just don't get it
Muff Wiggler
hope it all works out - troubleshooting can take some time but if it is any consolation, ultimately the damage will end up being far, far less that your worst fears about it, and you'll recover.

good luck!
SynthBaron
There might be a thermal overload/short device on the power supply. Probably let it cool down for a few hours then try it again.
Scot Solida
Thanks guys. I have heard back from Roger with a few suggestions, too (some of which echoed what you all are telling me).

As it stands, I am beginning to feel a little better... I plugged the top three rows into the Q-137 in the bottom cabinet (fed by the separate QPS1 power supply) and they seem okay. The Q-960 and STG things are trundling merrily along from that supply, and the oscs and ADSRs are fine, too.

That leaves only the middle two rows. I am about to start unplugging those modules to see if any are the culprits (but not before testing the QPS3 itself). It's a lotta modules, so it's going to take some time. waah
CZ Rider
Sounds like the -15 rail is not powering on after it was shorted. Isn't there a fuse on the -15 rail. I would check that first.
Scot Solida
Looks like the power supply. The -15 rail is still not lighting the -15v LED on the Q-101, even with all of the modules unplugged. I hope that it's nothing more than a fuse... and I hope that the rest of the modules are okay. So far, each that I have tested are fine, but there are a lot still to test...
SynthBaron
The only fuse is going to be on the power input module. And it's going to be one fuse only for the AC input, should be 3amps. There's no fuse on the power supply itself.
JohnLRice
Scot Solida wrote:
John: what should I be testing on the power supply? There is a five-hole jack that plugs into the power harness. IS that what I should check? What readings should I expect? I assume +/- 15 V and 5 V? (that aint anything like what I am getting by the way)


Hi Scot,

I don't have those specific DotCom power supplies here but I believe they are made with Power-One brand supplies so if you look on the chassis you'll be able to find the brand and model and then lookup the specs on the manufacturer's site.

When I switched from using the DotCom QPS2 wall-wart to using a DIY power-one supply I harvested the power leads that go to the modules and I had to figure out which colored wire was what. Here is what I determined for what it's worth:

mta Wire DC
Pin Color Voltage

001 White +15
002 (nc)
003 Red +5
004 Black Ground
005 Green -15
006 (nc)

FYI for those in the future doing a search on the QPS2 Elpac supply this is what I tested:
White = +15
Red = +5
Blue = Ground
Yellow = -15


Hey, OK, Synthesizers.com has a bunch of good info on their site!

Read the last half of this page:
http://www.synthesizers.com/technical.html#externalac

This picture may be handy BUT PLEASE USE CAUTION! MESSING AROUND IN THIS AREA IS DANGEROUS IF YOU DON"T UNDERSTAND WHAT IS WHAT! THERE IS EXPOSED 120VAC AND IT COULD KILL YOU, PLEASE DO NOT KILL YOURSELF!:
Scot Solida
Thanks John. That's good information... I'm going to take a break for dinner (if I can eat) and then get back to it.
suitandtieguy
good luck, man. i hope you haven't damaged anything.
Scot Solida
Thanks Eric... it looks at this point like the modules may have come through unscathed. I might have one bum Pan/Fade module. I think I may have fried the QPS3. Roger's been very cool about helping track the issue down and getting it fixed. He's gone far beyond the call of duty to help out. This kind of service and 1:1 communication is a good reminder of why buying from small manufacturers can be so beneficial to us musicians.
doctorvague
Hi Scot
I'm kinda late getting here, but I had a very similar problem to yours. The negative 15V LED would not light on the power entry module. It turned out I had bought a distro board from a third party that had 2 solder bridges that shorted the neg rail to ground. But even after I fixed the board the neg rail of the power supply still had problems. I ended up replacing the power supply. Not great, but still better than frying a bunch of modules. You have to disconnect everything from the supply except the power modules to know - or check the PSU outputs with a meter with nothing connected. Keep in mind there is a chance you might have both problems - a burned out module or 2 AND a faulty power supply. My PSU had no fuses to protect this sort of thing - I was a bit surprised by that.

good luck
Phil
Scot Solida
Thanks Phil. So far, the modules are testing out okay. There is obviously something up with the supply. Modules that didn't work properly on the big supply are running fine on the little one. With only the power modules hooked up to the suspect supply, I get no -15v LED action, so the supply needs to be fixed or replaced. The QPS3 goes back to Roger tomorrow or maybe even today. He'll take a look and see if he can wrangle it into working order. If not, I'll have to replace it.

Unfortunately, the remaining QPS1 can only power a fraction of my system, so the Big Fella is going to be hobbled until this is fixed.

I have now tested most of the modules that were obviously acting up and they all seem to be in working order. I hope this remains the case as I sift through them.
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