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stahlhart
Platinum Member
1318 Posts |
 Posted - 07/07/2007 : 15:54:00
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It looks like the board is a mixture of SMD and components with wire leads -- I'm not precisely sure by looking at the photos, but I'd wager that the Zener diode will have leads like the capacitor -- it looks like everything in the vicinity of the AC adapter input on the board is that way.
I agree that there's a whole science to destructive and potentially dangerous things you can do with electronics... I came close to becoming an accident statistic more than once in my childhood - such was life having a father who was/is both an electrical engineer and a bit of a pack rat. 
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 07/07/2007 : 16:49:22
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Hi Stahlhart & Guys
In one of his pictures-links, there seems to be a cylindrical device, under the glue, just behind the DC input socket, and in front of the cap.
Maybe this is the protection Diode-Zener, under all that glue,
it seems to be about the right size, & location.
Stahlhart Here is a hint, about the One SidChrome capacitor.
Queston 1.
What size capacitor & relative charge, will melt a 6 inch SidChrome open ended spanner, when dropped across it's terminals?
Question 2.
What intensity of light & color, will the melting spanner give off, in the resulting flash?
Answers, in another post soon.
SidChrome is the name of a company here in Australia, that manufactures premium spanners, sockets & other tooling, they carry a lifetime guarantee.
And for some unknown & strange reason,
the above scenario is not covered under the guarantee.
Regards Dr. Bob
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homestar_kevin
Copper Member
USA
34 Posts |
Posted - 07/07/2007 : 21:46:56
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So I pulled the broken diode and fired her up. She lives! works on both 9volt and adapters!! So happy!! thank you guys for everything! hopefully it'll keep on breathing!
Kevin |
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stahlhart
Platinum Member
1318 Posts |
Posted - 07/08/2007 : 03:41:00
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quote:
Originally posted by homestar_kevin
So I pulled the broken diode and fired her up. She lives! works on both 9volt and adapters!! So happy!! thank you guys for everything! hopefully it'll keep on breathing!
Good news. 
Probably still should replace those two parts, just to be on the safe side...
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 07/08/2007 : 07:29:24
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Hi homestar_kevin
Congratulation.. 
Just don't forget to wear protection, sorry replace the protection.
I really like my Vintage DD-2, so I can well imagine, that you are pleased with your NEW & FIXED DD-5
Regards Dr. Bob |
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homestar_kevin
Copper Member
USA
34 Posts |
Posted - 07/14/2007 : 07:14:11
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so i've been playing with her for a while now and I think i might like the dd-5 more than my dd-20 hahahaha
it's just simple straight forward fun.
best 20 dollar pedal I've bought in awhile 
thanks all
Kevin |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 07/14/2007 : 11:00:02
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Hi homestar_kevin
We are all really pleased that you managed to repair the DD-5,
and are so please with it's sound.
But please replace he protection diode, in case someone inadvertently
plugs in a wrong polarity plug pack.
Or simpler still, accidentally attempts to connect a new 9V battery, the wrong way around.
Remember the diode is also there to stop the reverse battery connection, & a new alkaline 9V, can put out a bit of energy, for a short time.
And it takes only micro seconds, to fry IC's & semiconductors..... 
Regards Dr. Bob |
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caloi
Copper Member
Philippines
5 Posts |
Posted - 08/05/2007 : 06:41:49
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Hello Everyone!
Also got a broken DD-5 for almost the same price as homestar-kevin, and tried to apply his fix by removing the protection diode.
But while troubleshooting the circuit I've found out that the voltage regulator (IC5) output is shorted to ground. I tried removing the voltage regulating circuit and still the 5v output terminal is shorted. I've checked the board for possible faulty soldering but everything looks clean. What do you think would be the cause of the shorted output. I've insert the image of the schematic and the things i've removed.
I'm also wondering what is the purpose of D3 in there, is that also a protection diode? Could I just remove it and will it work safely without it?
Download Attachment:  dd5(edited).JPG
281.64 KB |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/05/2007 : 08:54:48
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quote:
Originally posted by caloi
Hello Everyone!
Also got a broken DD-5 for almost the same price as homestar-kevin, and tried to apply his fix by removing the protection diode.
But while troubleshooting the circuit I've found out that the voltage regulator (IC5) output is shorted to ground. I tried removing the voltage regulating circuit and still the 5v output terminal is shorted. I've checked the board for possible faulty soldering but everything looks clean. What do you think would be the cause of the shorted output. I've insert the image of the schematic and the things i've removed.
I'm also wondering what is the purpose of D3 in there, is that also a protection diode? Could I just remove it and will it work safely without it?
Download Attachment: dd5(edited).JPG
281.64 KB
Hi caloi
Your link seems to be BAD ... I keep getting Error 404,
maybe the Path or Filename in the link is incorrect?
Just worked out the correct link for you.
uploaded/caloi/dd5(edited).JPG
The problem is, that the brackets, () are illegal characters in the filename.
You might have to get Bossarea to edit the filename so it displays.
If you cut and past the above link into a new browser page, it seems to work.
Regards Dr. Bob |
Edited by - Dr. Bob on 08/05/2007 09:15:29 |
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caloi
Copper Member
Philippines
5 Posts |
Posted - 08/06/2007 : 06:38:10
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Ooops! ...sorry about that.
Thanks Dr.Bob for correcting. Have you seen my image? What do you think could be the problem?
Ok I'll try to post the schematic again
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/06/2007 : 09:54:00
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quote:
Originally posted by caloi
Ooops! ...sorry about that.
Thanks Dr.Bob for correcting. Have you seen my image? What do you think could be the problem?
Ok I'll try to post the schematic again
Hi I tried to use this line of HTML to display your pic?
There is still something wrong with your file/filename.
[imgage]uploaded/caloi/dd-5.jpg[/imgage]
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Edited by - Dr. Bob on 08/06/2007 09:58:27 |
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caloi
Copper Member
Philippines
5 Posts |
Posted - 08/07/2007 : 05:59:28
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huh?! i saw my post yesterday and the image was there...
ok. let me try again to insert an image, hope this time it will work.
Download Attachment: DD5.JPG
285.01 KB |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/07/2007 : 09:37:54
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Hi caloi
Could you post up the rest of that Schematic & Overlay.
Or send it to me in a PM.
IC5 the 5V regulator is a 78L05
Package type T092 100mA regulator, like in the DD-2-2
These damage very easily with rev voltage & especially Over-Current.
Have you tried to replace it?
I have replaced many of these in various branded pedals.
Or did I misunderstand your description of the fault?
You may also have a faulty Q1 2SC2458, the transistor just after the protection diode.
Do not run the DD-5 with out the 5V regulator it powers IC6,
The unit will not operate without 5V on IC6.
I hope you didn't run 9V into IC6 after you removed the 78L05.
Replace the regulator with a known good one, & see if it all runs again.
Hope this helps.
Please don't forget to post up the rest of the DD-5 schematic & PCB overlays, & anything else yo might have.
Regards Dr. Bob
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caloi
Copper Member
Philippines
5 Posts |
Posted - 08/08/2007 : 06:38:06
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Dr. Bob,
That's the only copy I have and it's really scanned incomplete I guess.
Yes I've tried replacing the 78L05 but that didn't fix it. I think my main problem is that short between 5v supply and ground.
Don't worry I didn't run the unit without the voltage regulator. ;) What I mean on my previous post is that even if you try removing the voltage regulating circuit (IC5, C62, C63, C17 and including the protection diode), the 5v supply is still shorted to ground. Probably a component is causing this short.
What do you think the purpose of Q1 there? ...Do you think that also causes the 5v supply to short to ground?
Thanks for the very prompt replies Dr. Bob |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/08/2007 : 09:14:19
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Hi caloi
When you drew all the red text & graphics over the schematic, you obscured some of the circuit.
Any chance you can post up an unedited one.
I'm guessing that the transistor feeds the 78L05?
You might have to start removing components, to find the short on the 5V supply rail.
It is most likely a bypass cap, or maybe a solder splash.
It could be the Q1.
Actually try removing Q1 and see if the short is still there?
If you are going to start removing IC's, I would start with IC6
as when the 5V reg shorted out, it might have put full 9V onto IC6.
Get a very good magnifying glass, & in daylight, look for any obvious things that may be wrong.
A lot of stuff can be fixed by simple observation.
But please upload an unedited schematic, so we can see the whole circuit. It might help a lot to locate the short, or at least give some other suggestions.
Regards Dr. Bob |
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Topic |
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So I bought a broken dd5
DD5.JPG