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Stengah2010
Silver Member
Australia
167 Posts |
 Posted - 10/07/2009 : 09:56:11
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Hello all,
Yes another dead DD-3 story, I know what your thinking. 
Recently I picked up a cheap October 2004 DD-3 that is absolutely dead mint but also absolutely dead. It was sold with the disclaimer that at some point only moments into its short life it was plugged into the "wrong adaptor", ie. reverse or too high voltage and consequently is lifeless.
On opening her up I immediately spot a potential victim:
It appears the text on the top reads either 'P141 GS1G' or 'P441 GS1G'. I did a search for 'GS1G' and found a site that claims I'm photographing the carcass of a 'SMA4004 DIODE', so my question for all you techies is this a suitable replacement?
http://www.jaycar.com.au/productView.asp?ID=ZR1003&CATID=33&form=CAT&SUBCATID=712
I've soldered many a time but I've never attempted SMD so this could be interesting, luckily its one of the largest SMD components on the board. I couldn't see any other obvious damage on the board but who knows if anything else was taken out in the voltage apocalypse. First things first I'll change this little guy and see what happens... I'll keep you posted.
Thanks in advance. 
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/07/2009 : 10:33:55
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quote:
Originally posted by Stengah2010
Hello all,
Yes another dead DD-3 story, I know what your thinking.
Recently I picked up a cheap October 2004 DD-3 that is absolutely dead mint but also absolutely dead. It was sold with the disclaimer that at some point only moments into its short life it was plugged into the "wrong adaptor", ie. reverse or too high voltage and consequently is lifeless.
On opening her up I immediately spot a potential victim:
It appears the text on the top reads either 'P141 GS1G' or 'P441 GS1G'. I did a search for 'GS1G' and found a site that claims I'm photographing the carcass of a 'SMA4004 DIODE', so my question for all you techies is this a suitable replacement?
http://www.jaycar.com.au/productView.asp?ID=ZR1003&CATID=33&form=CAT&SUBCATID=712
I've soldered many a time but I've never attempted SMD so this could be interesting, luckily its one of the largest SMD components on the board. I couldn't see any other obvious damage on the board but who knows if anything else was taken out in the voltage apocalypse. First things first I'll change this little guy and see what happens... I'll keep you posted.
Thanks in advance.
The replacement looks fine to me.
D9 is the main protection diode. It's a smoking gun for having had an incorrect power supply plugged in.
Now... this type of diode usually fails "open". Can you measure the resistance across it? If it is a short circuit, it might have protected the rest of the pedal. If it is open circuit it might not have... To test the pedal, remove the diode and try the pedal with a battery (being careful to not touch the battery terminals around the wrong way!).
At the least, it is possible that you will need to replace some opamps. I've had a couple of these now with IC1 failed. Bit of a bugger to change the SMD opamp, but it can be done. |
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Stengah2010
Silver Member
Australia
167 Posts |
Posted - 10/07/2009 : 12:09:36
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Hey Laurie,
Ok I removed the diode, the track at the burnt end has slightly lifted off the board but if I'm careful hopefully it'll be fine. The multimeter says its short circuit so good start, next I put in a battery and guess what... the pedal works perfectly!
 
Wow, guess I'm lucky.
So thank you Laurie for helping me out sharing your knowledge.
I had a thought while I was awkwardly jamming the tip of my soldering iron up against the end of the diode, I guess I could replace it with a regular non-SMD diode and stand it up vertically with the tip of the leads soldered to the pads, but it would be nice to put it back as designed.
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/07/2009 : 12:13:59
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quote:
Originally posted by Stengah2010
I guess I could replace it with a regular non-SMD diode and stand it up vertically with the tip of the leads soldered to the pads
Yep, I've done this... it works. Check this thread out - my opamp repair is about the middle of the page
http://www.bossarea.com/forum/topic.asp?TOPIC_ID=6079
No worries about the help. I seem to be the DD-3 guy at the moment. |
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DD-3 Ressurection
