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voltz_shmoltz
Copper Member
7 Posts |
 Posted - 12/03/2008 : 15:50:56
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Hi everyone
This is my first post here and i really hope you could help me with a problem im having.
Yesturday i picked up a non-working dd3, the first version with the big chip, identical to the dd-2. Initially it was completely dead, but after removing protection diode (d6) it "sort of" came back to life. The reason i say sort of is because now although it passes dry signal when bypassed , it doesnt turn on in any of the modes except hold (which is still better than before since then it didnt turn on at all, and there was no dry signal). And when hold is selected the indicator led turns on immediately ( which if im correct shouldnt happen unless the switch is engaged) and the output becomes a mix of the dry signal plus the held signal ( as if the pedal was pressed in hold mode and the output mixed with the dry signal).
I've checked all the 9V, 5v, etc voltages and they all seem to be correct. So i dont think its the voltage regulator, but perhaps one of the ic's or transistors related to the switching circuitry is malfunctioning... like q11, q12, or IC9... can any one comment on this?
any help is much appreciated |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/03/2008 : 16:07:10
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Hi voltz_shmoltz
Welcome to the forum from Australia.
Can you give us some more background on what happened to it?
Over-volts? Reversed-Volts?
Do you have the DD-2/3 Schematic?
The links are in the Tech section.
Have you also checked the Electro's on the DC input?
Was D6 shorted or open circuit? ( Much better if it was shorted).
Did you replace it with a 11V or 12V 1W Zener? not a standard diode.
Are you using the correct voltage, the early stuff used the ACA adapter, not the 9V PSA.
Does it work on a (known good) 9V Battery?
Regards Dr. Bob
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Edited by - Dr. Bob on 12/03/2008 16:08:07 |
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sp-1
Platinum Member
Germany
1454 Posts |
Posted - 12/03/2008 : 16:52:55
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I believe all DD's use a psa adaptor.
Hooked up my dd-3 version 2 once to a 9v adaptor but it turned out that it delivered 14v and got the same problem, only the dry signal came through. Hooked it up with a boss psa and it worked fine, so I think DD's can't take higher voltages.
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Edited by - sp-1 on 12/03/2008 16:53:48 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 12/03/2008 : 18:03:59
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EXACTLY the same thing has happened to me... accidentally used an ACA adapter and same symptoms as described. Went back to PSA and all is well.
So... are you using a PSA adapter or a 9VDC regulated supply of some sort? |
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tony
Bronze Member
United Kingdom
142 Posts |
Posted - 12/03/2008 : 18:36:23
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My bought dead DD 2 has exactly the same problem:
http://www.bossarea.com/forum/topic.asp?TOPIC_ID=5866
I though it might be a dead switch but no.
Bound to be something around the BA634
Tricky one.
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Edited by - tony on 12/03/2008 18:43:52 |
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voltz_shmoltz
Copper Member
7 Posts |
Posted - 12/03/2008 : 20:40:30
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i have no idea what originally happened to it. but d6 was burned ( it was all black around it). i am using a boss power supplu , the psa one. and just replaced the diode with a zener 11v..and the voltage regulator with a new one...same symptoms...
in a way im glad to hear some one was having the same problems as me, i just hope it can be figured out... so far, looking at the schematic, it seems that if the led lights up by itself it in hold mode it should mean
that either Q11 activates without any base current applied to it, or there is a constant base current applied to it..one way or another, q11 seems to be always on...even with the switch not engaged... and this is as far as my reasoning got me :) |
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tony
Bronze Member
United Kingdom
142 Posts |
Posted - 12/03/2008 : 22:44:24
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quote:
Originally posted by voltz_shmoltz
i have no idea what originally happened to it. but d6 was burned ( it was all black around it). i am using a boss power supplu , the psa one. and just replaced the diode with a zener 11v..and the voltage regulator with a new one...same symptoms...
in a way im glad to hear some one was having the same problems as me, i just hope it can be figured out... so far, looking at the schematic, it seems that if the led lights up by itself it in hold mode it should mean
that either Q11 activates without any base current applied to it, or there is a constant base current applied to it..one way or another, q11 seems to be always on...even with the switch not engaged... and this is as far as my reasoning got me :)
You're totally right.
When in s,m and l modes, with power switched through the flip flop, it acts like it's in a permanent "five second mute". I don't quite understand how this knocks onto Q11 and the hold function.
I've got a few bits and pieces here and I'll try out a couple of things tomorrow.
Will keep you posted. |
Edited by - tony on 12/03/2008 22:50:36 |
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tony
Bronze Member
United Kingdom
142 Posts |
Posted - 12/04/2008 : 01:51:26
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voltz_schmoltz, go here (end of page 2):
http://www.bossarea.com/forum/topic.asp?TOPIC_ID=5866
I think I've found our problem (It works for me and I hope, for you, too). The track next to D6 supplies R59 with 9v and is very thin. Mine fried along with D6. I bridged it and now all is peachy. |
Edited by - tony on 12/04/2008 01:52:32 |
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DeFrag
Moderator
USA
3409 Posts |
Posted - 12/04/2008 : 04:02:11
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Welcome to Bossarea voltz_shmoltz!  |
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voltz_shmoltz
Copper Member
7 Posts |
Posted - 12/04/2008 : 04:32:07
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Thanks DeFrag
Tony, its great u got yours fixed, actually after messing about with mine i found the same exact problem, which worsened after the board got exposed to all the heat i applied while replacing the diode. now the whole area is pitch black with much of the trace gone so im not even sure how to retrace it. But im gonna try :p
either way congrats and thanks for the inspiration
( good to know that its actually fixable :) )
cheers |
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voltz_shmoltz
Copper Member
7 Posts |
Posted - 12/04/2008 : 05:51:20
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Tony, Dude!!! thank you so much. after reading your post i decided to retrace the burnt off area, and i did. The result is, the pedal works! and it sounds great.
Thank you again for the idea
and thanks everyone else that replied
cheers |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 12/04/2008 : 06:19:39
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Ahhh... it's fixed! Great stuff! tony has more knowledge about these things than anyone here, so you were in good hands!
I was just about to upload a pic of what that corner of the board looks like without burns. What the heck - here it is anyway. This is mine after D6 replacement. I was very lucky that there was almost no burning.
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/04/2008 : 08:12:19
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Hi voltz_shmoltz & Guys
Great to hear it's all working now.
There are some really talented & knowledgeable people here.
I hope you hang around for a bit, now that your pedal is working again.
It sounds like you have some background/experience in electronics.
It would be good to have another Tech on board...
Regards Dr. Bob |
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Topic |
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DD3 Needs Help!
