[sdiy] Korg DW-8000 power supply help?

[Tony Kalomiris]

Check IC2 and IC3 , both of those 7805 regulatos were defective in an EX-8000 - rack version of the DW-8000 - I serviced recently.


Tony Kalomiris


On 2010-11-03, at 1:43 PM, Harry Bissell wrote:

> ohmmeter across the power supply outputs... look for short circuits.
> 
> Suspect failed electrolytic caps...
> 
> I assume that with the transformer disconnected, you got reasonable AC
> voltages, and that you checked the bridge rectifier (ohms) out of the circuit.
> With the bridge rectifier out, you could easily meter any shorts...
> 
> H^) harry
> 
> 
> 
> 
> 
> ----- Original Message -----
> From: Eric Frampton <eric at ericframpton.com>
> To: SDIY <Synth-diy at dropmix.xs4all.nl>
> Sent: Wed, 03 Nov 2010 13:29:44 -0400 (EDT)
> Subject: [sdiy] Korg DW-8000 power supply help?
> 
> Hi all -
> 
> I'm trying to troubleshoot a failed Korg DW-8000 power supply. Disconnected from any load it pops fuses as soon as it's powered up. I started with the bridge rectifier, it's fine; while it was removed I checked the xformer, it's fine. There doesn't appear to be anything irregular (trace damage, burns, blown bits, etc.) on the board.
> 
> Do you guys have any techniques you can share for where I might start with this thing, since I can't power it up at all? It's not like there's just one rail down and I can fire up the rest of it to test.
> 
> And yes, I realize I'm dealing with potentially lethal voltages and I won't hold any of you accountable if I screw up my own handiwork.
> 
> Thanks,
> Eric
> 
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> -- 
> Harry Bissell & Nora Abdullah 4eva
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