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Plectrum_Fingers
Copper Member
United Kingdom
15 Posts |
 Posted - 12/07/2006 : 14:35:25
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I picked up a dm2 the other day for �2.50 (bargain of a lifetime!)
When I first plugged it in no delay was present so I suspected the previous owner had fiddled around with the the trim pots. So I opened it up and found the sweet spots and soon got the delay going again.
One problem is that the repeat rate pot seems a bit funny. I think that its been replaced with the wrong type and value. Its fine up to a certain point but then it it starts to feedback endlessly - even if the feedback pot isnt up full. The range seems a bit bunched up towards the end to so i'm guessing its the wrong pot.
Does anyone know what the pot is?
Also, does the repeat rate go from 0 = long delay, to full = short delay? Or is it the other way round? As I'm sure that on my DM2 that i had a few years ago it was the other way round, so if it is, the pot has been replaced and wired in reverse.
look forward to any replies.
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stinkfoot
Silver Member
Sweden
181 Posts |
Posted - 12/08/2006 : 09:38:53
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It should go from short (0) to long (10) delays, so someone has wired it wrong. According to the schematic, the pot should be a 1M lin, so check your pedal to see what's in there.
/Andreas |
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Plectrum_Fingers
Copper Member
United Kingdom
15 Posts |
Posted - 12/08/2006 : 10:00:57
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Just as I thought. I've checked the pot out its not linear but it is 1m.
Thank you very much stinkfoot!
Also, the output level isn't very high even when the delay is not turned on. What do you think could be causing this problem?
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Plectrum_Fingers
Copper Member
United Kingdom
15 Posts |
Posted - 12/08/2006 : 12:07:36
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okay, just had a good long look at the components and found that the zener diode D3 (rd56eb3)has rotted away.
I've searched the internet looking for a RD56EB3 but I cant find one anywhere. Is there an alternative?
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silvertone6120
Gold Member
USA
609 Posts |
Posted - 12/08/2006 : 23:11:10
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quote:
Originally posted by stinkfoot
It should go from short (0) to long (10) delays, so someone has wired it wrong.
/Andreas
Are you sure about that? If that's the case I have three DM-2s and a DM-3 that are wired wrong.
All of mine go from long at 0 to short at 10. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/09/2006 : 15:33:49
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quote:
Originally posted by Plectrum_Fingers
okay, just had a good long look at the components and found that the zener diode D3 (rd56eb3)has rotted away.
I've searched the internet looking for a RD56EB3 but I cant find one anywhere. Is there an alternative?
Hi Plectrum_Fingers
Please private mail me, a copy of the schematic that you have.
I will take a look at it, & try to help you out with the zener
type or a substitute.
Just going by the part number, I would hazard a guess that it's a 5.6V 400mW or 1W type.
Does it feed the main circuit or the LED indicator?
I will know when I see the schematic.
Regards Dr. Bob 
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Plectrum_Fingers
Copper Member
United Kingdom
15 Posts |
Posted - 12/09/2006 : 17:28:20
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Thanks for your reply Dr Bob.
i've found a subsitute zener so it should be coming soon. I think it powers the led as that is no longer working. although it was working intermittently when i first tried it and after i removed the worn away diode it didnt work at all.
Anyway, it appears I have a new problem now.
As I was packing away for the day, I could smell something burning. I thought it was the soldering iron but that wasnt turned on. So I had a sniff of the pedal and my worst fears were confirmed. I think something has been fried. I have no idea how this happened though, there was nothing making contact with something it shouldnt.
Anyway, as a result of this, the delay actually doesnt work anymore.
The smell seemed to be coming from the same region as where the zener diode was so any ideas what this could be?
This �2.50 bargain of the century has now turned into the pain in the arse of the century.
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tomwest
Silver Member
United Kingdom
436 Posts |
Posted - 12/09/2006 : 18:23:24
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| Well, it's only �2.50, and you could probably sell it on broken for more than that. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/10/2006 : 02:29:24
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Hi Plectrum_Fingers
Maybe the the zener is in the wrong way, maybe it wasn't a zener.
Maybe it's the resistor, that's part of the zener to LED circuit.
If your going to sell it?
Put me down for first option.
I love DEAD stuff.
Regards Dr. Bob
Hey Plectrum_Fingers, can you please still send me a copy of the schematic.
Dr. Bob
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Plectrum_Fingers
Copper Member
United Kingdom
15 Posts |
Posted - 12/11/2006 : 12:00:57
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yeah, i might let it go. I'd rather it go to a loving home than stick it on ebay.
PM me with an offer or something. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/11/2006 : 13:54:24
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quote:
Originally posted by Plectrum_Fingers
yeah, i might let it go. I'd rather it go to a loving home than stick it on ebay.
PM me with an offer or something.
Hi Plectrum_Fingers
I just went to PM you but you didn't leave any details or email address, when you setup your Profile. 
You will find my details in my members profile.
Just click on my name, on the left side of any pf my replies.
PM me & let me know what you might want for it.
One of my boys has a paypal account, else let me know how you would like the payment.
I do know that Her majesty's Mail to Australia can be a killer,
I once got a laptop motherboard off EvilBay & it cost me as much to have it posted from the UK.
Regards Dr. Bob
PS Will you please PM the schematic that you have?
I might still be able to help you repair it, for yourself.
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Topic |
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DM-2 Repeat Rate pot
