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tony
Bronze Member
United Kingdom
142 Posts |
 Posted - 11/26/2008 : 22:28:55
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Came across this nicely priced non functioning DD2 so I snapped it up.
Serial number is 602900.
The pedal does not power up at all.
I'm hoping for a relatively straightforward fix. D6 is clearly toast:
You can actually see a brown spot on the top left of the plastic insulator in the above picture (it was in back to front).
Other than D6, the board is really immaculate.
Thankfully, no one seems to have gone anywhere near the board or anything else for that matter.
It's interesting to note the subtle differences between this one and DD-2 no. 1. Many of the components on the board are noticeably smaller. Obviously all the chips are the same size but all the resistors and caps (film and electrolytic) are definitely slightly more miniaturized than on my other example, particularly the electrolytics. As a result the board is much easier to navigate.
Cosmetically, I'm gonna go down the Laurie path of a respray. The foot pedal is in really nice condition so it's just the main case that needs it. Fortunately, my local Halfords has a frankly baffling array of variants on the theme of "pearl white".
On a different note, here's that evil q9 from DD-2 one (I never did update that other thread), with a bit of it's top missing (I wanted to see what it looked like inside)
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Edited by - tony on 11/26/2008 22:37:23 |
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ChristoMephisto
Platinum Member
Canada
1288 Posts |
Posted - 11/27/2008 : 00:40:25
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| Nice score, same thing happened to my DD3 with the burnt zener |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/27/2008 : 01:54:10
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Yeah, it will almost certainly be D6. Use your multi-meter to test ohms across D6 both ways - if it reads short, replace it and all should be fine  |
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DeFrag
Moderator
USA
3409 Posts |
Posted - 11/27/2008 : 01:57:12
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Here's in hopes for the easy fix.  |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/27/2008 : 02:41:06
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Hi tony
Nice find, and it looks like you will be in luck with just D6 shorted.
As Laure said, test D6 for shorts both ways.
But if it's open, you may have a damaged 78L05 100mA regulator,
it looks and is the size that PITA Q9 transistor, from your other DD-2.
Can I ask how much you paid for this one?
Regards Dr. Bob
4200 |
Edited by - Dr. Bob on 11/27/2008 02:41:32 |
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tony
Bronze Member
United Kingdom
142 Posts |
Posted - 11/27/2008 : 04:38:35
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quote:
Originally posted by Dr. Bob
Hi tony
Nice find, and it looks like you will be in luck with just D6 shorted.
As Laure said, test D6 for shorts both ways.
But if it's open, you may have a damaged 78L05 100mA regulator,
it looks and is the size that PITA Q9 transistor, from your other DD-2.
Can I ask how much you paid for this one?
Regards Dr. Bob
Yeah, IC10. I've got a little vacuum sealed bag of 5 78L05's from before!
I paid just under �30.00, which might not seem that great a score in the mythical internet forum world of of amazing gear deals ("I picked up a NIB VB-2 and DM-3, along with a mint JMI AC30 with tags for twenty bucks from a pawn shop guy who didn't know what he had" etc. etc. etc. etc.), but when it's done (for virtually no additional expense), I'll have a great, rock solid long chip BOSS delay that might be a good platform for a well conceived mod, so I'm happy.
Edit:
D6 is shorted both ways. 
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Edited by - tony on 11/27/2008 04:56:42 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/27/2008 : 05:39:53
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quote:
D6 is shorted both ways.
Good.
Do you have some 11V - !2V or 13V, 1 Watt zener diodes to replace it with?
You do know you can test it once the shorted D6 is removed.
But be SUPER CAREFUL that you apply the correct polarity to the Pedal.
Also check the elecro's (Caps) around the zener, especially that C49 in case of overheating, the PCB didn't look all that burnt, from the pic you uploaded.
Hey tony, did you also get the strange looking grey metallic shield?
I didn't see it in the pictures.
Is the lettering on the plate White or cream?
Good luck
Looks like you have a good one.
Regards Dr. Bob
PS... YELLOW wire (9), next to C49, has a little bit too much copper exposed, you might want to push the sleeving down a bit, you can usually get the insulation to slide the little distance down the wire, with out re-soldering it.
Regards Again Dr. Bob |
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tony
Bronze Member
United Kingdom
142 Posts |
Posted - 11/27/2008 : 14:00:56
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The foil shield is there, just not in the picture.
Got all the stuff. Maplin in the UK do come through sometimes. They had the exact part - an 11v 1w (1.3w) zener.
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Edited by - tony on 11/27/2008 14:06:00 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/27/2008 : 15:35:22
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| Sooo.... does it work?? |
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tony
Bronze Member
United Kingdom
142 Posts |
Posted - 11/27/2008 : 17:27:50
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| Haven't had a chance yet, I'll get to it tomorrow! |
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Rid
Bronze Member
Denmark
87 Posts |
Posted - 11/28/2008 : 00:08:59
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Cool....love mine....modded it, then I removed the mods again...like it stock better....something about those hazy repeats.
Hope it will be an easy fix.
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tony
Bronze Member
United Kingdom
142 Posts |
Posted - 11/28/2008 : 18:06:51
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OK, well, some good news, some bad news...
With the new diode the pedal powers up great and passes a strong clean signal either on or in bypass. There are, however, some really weird switching issues.
In summary, it does the opposite of what it should do. The DD 2/3 is supposed to switch on in s,m and l modes but not in hold mode unless the footswitch is kept depressed.
In modes short,med and long there is no power to the effect at all (dry signal still bypasses). In hold mode, the pedal powers up switched on and stays on. In all instances, the footswitch (which tests fine) has no effect - it doesn't turn the s,m,l modes on and it doesn't turn the hold mode off.
A quick fix? Me? HaHaHaHa....
What was I thinking?
At least I know where the problem is this time.
Also, I think my multimeter might not be working - I cant read any voltages at all out of this pedal, on or off, even when I can hear it repeating in hold mode!! |
Edited by - tony on 11/28/2008 18:17:29 |
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DeFrag
Moderator
USA
3409 Posts |
Posted - 11/28/2008 : 19:53:52
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| Buy a Fluke! |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 11/28/2008 : 20:14:26
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quote:
Originally posted by tony
OK, well, some good news, some bad news...
With the new diode the pedal powers up great and passes a strong clean signal either on or in bypass. There are, however, some really weird switching issues.
In summary, it does the opposite of what it should do. The DD 2/3 is supposed to switch on in s,m and l modes but not in hold mode unless the footswitch is kept depressed.
In modes short,med and long there is no power to the effect at all (dry signal still bypasses). In hold mode, the pedal powers up switched on and stays on. In all instances, the footswitch (which tests fine) has no effect - it doesn't turn the s,m,l modes on and it doesn't turn the hold mode off.
A quick fix? Me? HaHaHaHa....
What was I thinking?
At least I know where the problem is this time.
Also, I think my multimeter might not be working - I cant read any voltages at all out of this pedal, on or off, even when I can hear it repeating in hold mode!!
Just as well you have all that previous experience... 
Give us some measurements around the switching elements when you get the multimeter going. |
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tony
Bronze Member
United Kingdom
142 Posts |
Posted - 11/28/2008 : 20:43:48
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This is weird. The multimeter works fine - I can get 9v between the inside and outside of the adaptor barrel jack no problem.
But from the back of the DC board onwards, simply nothing at all. Yet there is some voltage in the pedal, somewhere.
Bossarea/ Dr Bob, any chance you could move this thread to "modifications and technical issues"? I don't want to clog up the main board with what might prove to be a lengthy thread...
Some reflection needed on this one, I feel. |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 11/28/2008 : 22:08:49
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I've moved the topic.
The pedal is often grounded through the input jacks or pots so if it's still spread out across the table you might experience that the voltages doesn't make sense at all. |
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New DD-2 day.
