Korg 01/w hissing.
2015-01-02 by xp_sucks@...
Hello all. Greetings and a happy New Year. The New Year holidays have given me some more time to investigate my 01/W however its not back yet.
The story so far...
A friend of mine borrowed it for a session and it came back with hissy outputs. Sure enough C99 and C100 had burst sending electrolyte all over. Foolishly I left it in this state over last summer in a warm part of the house. I finally got round to fixing it. I've cleaned the splatter at least 7 or 8 times with IPA (No not India Pale Ale), I replaced those caps for higher rated electrolytics, I've replaced R142 and R143. Although the hiss is a little reduced and sometimes after a boot I may have up to 5 minutes of hiss-less use, it will always return. All outputs are affected Phones, 1,2,3 & 4 although 3 and 4 sometimes are not affected, or less affected depending on the patch. Connector 100 which is probably an audtio test point also has hiss. The voltage regulators IC52 and IC53 are doing their job and there is just under +/- 5v in the outputs of those IC's.
I have remade any dodgy tracks and the board is once again clean.
Using a very simple signal tracer (Audio amp plus a .1uf capacitor as a probe), I traced it back to the DAC stage. IC34, IC35, IC37 all have hiss on their audio outputs so I'm thinking that its probably in the digital domain.
I do not have any test equipment other than my probe and a multimeter. In other words I don't have a scope or a logic probe. (I've been toobBusy and lazy to purchase and learn hot to use them correctly) Has anyone had this problem and solved it? Does anyone know where, if push comes to shove I can obtain a replacement motherboard part No. Korg KLM 1528B?
Many thanks in advance and best regards
Tee.
The story so far...
A friend of mine borrowed it for a session and it came back with hissy outputs. Sure enough C99 and C100 had burst sending electrolyte all over. Foolishly I left it in this state over last summer in a warm part of the house. I finally got round to fixing it. I've cleaned the splatter at least 7 or 8 times with IPA (No not India Pale Ale), I replaced those caps for higher rated electrolytics, I've replaced R142 and R143. Although the hiss is a little reduced and sometimes after a boot I may have up to 5 minutes of hiss-less use, it will always return. All outputs are affected Phones, 1,2,3 & 4 although 3 and 4 sometimes are not affected, or less affected depending on the patch. Connector 100 which is probably an audtio test point also has hiss. The voltage regulators IC52 and IC53 are doing their job and there is just under +/- 5v in the outputs of those IC's.
I have remade any dodgy tracks and the board is once again clean.
Using a very simple signal tracer (Audio amp plus a .1uf capacitor as a probe), I traced it back to the DAC stage. IC34, IC35, IC37 all have hiss on their audio outputs so I'm thinking that its probably in the digital domain.
I do not have any test equipment other than my probe and a multimeter. In other words I don't have a scope or a logic probe. (I've been toobBusy and lazy to purchase and learn hot to use them correctly) Has anyone had this problem and solved it? Does anyone know where, if push comes to shove I can obtain a replacement motherboard part No. Korg KLM 1528B?
Many thanks in advance and best regards
Tee.