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Witek
Copper Member
Canada
5 Posts |
 Posted - 10/02/2007 : 16:03:08
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So I bought a dead boss dd3 for $5 in hopes of fixing it up, if I can't fix it, it's to the scraps with the parts and the housing to build other toys with.
This is the Version 1 board I am talking about, the one that's identical to the DD2 board.
I swapped the diode in it that protects the pedal from the wrong type of adapter. But it still does nothing.
I did manage to get a bit of it working properly. It now lights up like it should and bypasses. But there is no effect still. I'm thinking there's something wrong on the signal path leading up to the repeat chip.
I did however manage to get something on it working aswell, kinda. When you plug a patch into the direct out jack and just listen to the signal coming out of the wet output it does delay the signal once properly, so I can assume there's a problem with the looping part of the signal aswell. You do aswell hear a really really low effect coming from the pedal, so I know the chip isn't fried.
I tried the voltage regulator and got:
Between the ground and the +5v I'm getting 10.2V?
And the ground and +9V I'm getting 15V.
Or is the Ground -5V? so I'm just getting the potential difference?
This one may be all over the board, but I'm just copying and pasting from another forum which didn't help me much. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/02/2007 : 18:30:22
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Hi Witek
Welcome to the forum.
Can I ask, what country are you from?
Now for the DD-5
If the rev Protection Diode was blown?
Replace the Pos 5V regulator 78L05
check any op-amps, they fry really quickly once they have reverse
voltage-over voltage applied to them.
You did say that you already replace the Rev, Voltage protection diode.
So I am assuming that it had, Rev Volts applied to it.
And that's why you should check any and all op-amps.
Do you have the DD-2-3 schematic to work from? it's on a few sites on the web, if you need to find it.
Good Luck
Hope this helps out a bit.
Nice price for the dead DD-3,
even better if you finally get it going.
Regards Dr. Bob |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 10/02/2007 : 19:39:14
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| You can often get tricked when measuring voltages while the pedal is disassembled. The PCB is sometimes grounded through the jack sockets and if you get a different potential on the case and PCB you can get unpredictable results. Ground should be 0V and there should not be any voltages higher than your supply voltage. |
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Witek
Copper Member
Canada
5 Posts |
Posted - 10/02/2007 : 20:08:14
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quote:
Originally posted by Dr. Bob
Hi Witek
Welcome to the forum.
Can I ask, what country are you from?
Now for the DD-5
If the rev Protection Diode was blown?
Replace the Pos 5V regulator 78L05
check any op-amps, they fry really quickly once they have reverse
voltage-over voltage applied to them.
You did say that you already replace the Rev, Voltage protection diode.
So I am assuming that it had, Rev Volts applied to it.
And that's why you should check any and all op-amps.
Do you have the DD-2-3 schematic to work from? it's on a few sites on the web, if you need to find it.
Good Luck
Hope this helps out a bit.
Nice price for the dead DD-3,
even better if you finally get it going.
Regards Dr. Bob
Hi, thanks for the response.
I'm from Canada.
Yeah I have the schematic that I've been working from. How would I check the opamps to see if they're good or fried? |
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pedals 4 pv
Platinum Member
Canada
1351 Posts |
Posted - 10/02/2007 : 20:50:15
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hi witek welcome to the forum, If your from Canada post it so everyone can see It makes them very jealous. Good luck with your DD-3 and may many Timbits come your way. |
Edited by - pedals 4 pv on 10/02/2007 20:50:54 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/03/2007 : 02:01:04
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quote:
Originally posted by Witek
Hi, thanks for the response.
I'm from Canada.
Yeah I have the schematic that I've been working from. How would I check the opamps to see if they're good or fried?
[/quote]
Hi Witek
There are many technical & non-technical ways,
you could run a signal injector into the inputs & look at the outputs on CRO, - or measure the voltages on the various pins relative to ground-negative, comparing your results with a known good one.
Or simply remove them, clean the pins, solder in some good quality IC sockets, & replace them, with new ones.
Read my walk through about repairing am Ibanez DL5 & how many opamps & regulator & stuff, went to Pedal Smoke Heaven, it's in the Tech & mods section, a couple of pages down the list.
But as BOSSAREA mentioned in his post above, make sure you have a good & continuous earth-ground-negative connection.
You can do this by connecting some crocodile or test clips between the connections that would normally be attached to the metal case of the pedal.
Take you time, my guess is the 78L05, I have replace many of these on various brands of pedals.
Good Luck,
Mail Christo & see if he lives close to you, he's here on the forum, lives in Canada & love to do tech stuff to pedals
Oh yeah & he's a really great guy... 
Regards Dr. Bob |
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Witek
Copper Member
Canada
5 Posts |
Posted - 10/11/2007 : 05:00:47
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| Ok, so I replaced the 7805, and it did solve the trick. But now the pedal seems to be acting up in a different way. The repeated signal is very distorted and clipped, and just sounds like crap. It also keeps on repeating on it's own slightly when not at full feedback. When the pedal is in bypass, it takes the dry signal passing through and repeats it once all clipped and distorted. The volume for it and all the controls seem to work fine, but the pedal doesn't sound good. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/11/2007 : 08:26:13
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quote:
Originally posted by Witek
Ok, so I replaced the 7805, and it did solve the trick. But now the pedal seems to be acting up in a different way. The repeated signal is very distorted and clipped, and just sounds like crap. It also keeps on repeating on it's own slightly when not at full feedback. When the pedal is in bypass, it takes the dry signal passing through and repeats it once all clipped and distorted. The volume for it and all the controls seem to work fine, but the pedal doesn't sound good.
Hi Witek
As I mentioned in an earlier post, when you reverse polarity most pedals, you will also fry/damage some of the op-amps.
as these are connected directly to the supply, & not via the regulator that also just went south.
It all depends how the protection diode decided to die, if it went short, that's the best way, as it protects the circuit.
But if it went open circuit, then it's likely that all the reversed voltage & over voltage, got to the op-amps.
Can you remind me what state the protection diode was in?
Short or open, or just a small pile of smelly bits...
Buy some sockets & start replacing, op-amps, the ones near the input & output are the most likely candidates.
But don't be surprised that you replace all of them.
While your at it, check any transistors & FET's.
If you have the older long chip version, check the 5218 op-amp, it's common to input & output & it's also in circuit when it's bypassed.
Also is it the modern DD3 with the surface mount delay processor, or is it the LONG chip older one?
The NE570 Compander IC may have also been damaged, but I would look at the op-amps first.
If you can get a CRO & sig. Gen. run a low level signal into it & trace it out, see where the distortion component is coming from.
Regards Dr. Bob |
Edited by - Dr. Bob on 10/11/2007 08:27:09 |
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bossarea
Forum Admin
United Kingdom
3652 Posts |
Posted - 10/11/2007 : 10:42:59
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Are there any trimpots in the DD-3?
Maybe it's now actually working but needs to be calibrated? The analog pedals could sound like you describe if someone fiddled around with their trimpots. The digital pedals don't have the same need for timing of a BBD so I'm not sure if it still applies or not. |
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ChristoMephisto
Platinum Member
Canada
1288 Posts |
Posted - 10/11/2007 : 13:44:28
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There are two trim pots within the dd3.
The clock high and clock low,
and are connected to the delay pot.
All that stuff Dr.Bob writes about makes me realize how much of electronics there is left to discover
Surprised there isn't a thread about troubleshooting Boss pedals, what to look for and how to fix it. Collectively with all our pedals and technical know how (some more than others) could bring any boss pedal back to life
Welcome to the forum, good score on the $5 dd3 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/11/2007 : 16:25:49
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quote:
Originally posted by ChristoMephisto
There are two trim pots within the dd3.
The clock high and clock low,
and are connected to the delay pot.
All that stuff Dr.Bob writes about makes me realize how much of electronics there is left to discover
Surprised there isn't a thread about troubleshooting Boss pedals, what to look for and how to fix it. Collectively with all our pedals and technical know how (some more than others) could bring any boss pedal back to life
Welcome to the forum, good score on the $5 dd3
Hi ChristoMephisto
Thanks for your support Christo.
I still believe that the forums' collective knowledge, & especially its friendly attitude, is the main reason we, manage to solve so many problems & issues.
Or put simply, the forum is so much more, than the sum of it's parts.
Just getting back to the Technical & repair issue.
Sometimes you just have to get out the heavy metal (Test Equipment).
Like the CRO (Cathode Ray Oscilloscope)& The Signal Generator.
And all the digital/analog IC databooks-sheets.
Regards Dr. Bob  |
Edited by - Dr. Bob on 10/11/2007 16:33:29 |
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Witek
Copper Member
Canada
5 Posts |
Posted - 10/11/2007 : 16:45:43
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| Have an oscilloscope (another great find - $10 at a garage sale) but no signal gen. haha. And yes, this place is much more friendly than other forums I've posted at. I like it here. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/11/2007 : 16:59:36
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quote:
Originally posted by Witek
Have an oscilloscope (another great find - $10 at a garage sale) but no signal gen. haha. And yes, this place is much more friendly than other forums I've posted at. I like it here.
Hi Witek
A CRO for $10
What a great find..
You have to upload some pics of that one..
As far as the Sig. Gen goes, you can use almost anything that makes some noise, even an old cassette tape recorder.
OR better still a mall keyboard, even some kids toys.
It's just really hard to keep strumming the guitar, while you have the CRO probe in your other hand, trying trace through the circuit.
Regards Dr. Bob |
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Witek
Copper Member
Canada
5 Posts |
Posted - 10/11/2007 : 17:14:45
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quote:
Originally posted by Dr. Bob
quote:
Originally posted by Witek
Have an oscilloscope (another great find - $10 at a garage sale) but no signal gen. haha. And yes, this place is much more friendly than other forums I've posted at. I like it here.
Hi Witek
A CRO for $10
What a great find..
You have to upload some pics of that one..
As far as the Sig. Gen goes, you can use almost anything that makes some noise, even an old cassette tape recorder.
OR better still a mall keyboard, even some kids toys.
It's just really hard to keep strumming the guitar, while you have the CRO probe in your other hand, trying trace through the circuit.
Regards Dr. Bob
I have used a keyboard of mine to generate a square wave before, but I'd have to get that from my parents' house. I could simply use a computer based synth and plug it into the pedal.
Oh and I forgot to mention, this is the early version of the dd3 with the big chip across the board. The same one as the dd2. |
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Another DD3 Problem.
