[sdiy] finding a short in a Yamaha CS-50/CS-80

[Csaba Zvekan]

>>> Am 28.10.2008 um 21:38 schrieb jpitt at fhcrc.org:
>>>
>>>> Do I have to desolder every single +15 and -15 line off every  
>>>> board  to track down the short or is there an easier way?

jpitt

Yes, you have to. Then measure it board by board. Narrow it down to  
the board. Then measure the caps first. I don't know any other way.

Csaba



Bob,

Which exact YAMAHA custom IC do you need ? The IG00156 or if you are  
lucky it's just another IG00151 ? Perhaps it's a bad cap in the VCF  
section ? Have you checked ?

Csaba

On Oct 29, 2008, at 7:35 PM, Bob Weigel wrote:

> OH yeah absolutely check the tantalums for shorts.  The worst  
> problems I've seen in these units though were from when the power  
> supply of a cs-20m had a regulator problem where it overvoltaged  
> everything.  I'm still dealing with that.  Anyone have a vcf they  
> want to sell me?  The vcf leaks slightly making a crappy irritating  
> subtle noise. I need to scrap something else to get VCA's and a  
> VCF.  If you ever see an organ getting tossed from that era SNAG IT  
> because some of the parts are the same. 1976 is too early; all  
> transistor usually on those organs.-Bob
>
> Csaba Zvekan wrote:
>
>> Ingo is right check the tantalum capacitors . They are all over  
>> the  place. I remember having a short on one of the TBS boards.  
>> Check TBS1  or TBS2 boards there are plenty of tantalum 0.33uF s  
>> there.
>> It's a good practice to replace all of them tantalums anyway today   
>> it's this guy here tomorrow on another board. If you know what I  
>> mean.
>> Is it a CS-50 or CS-80 ?
>>
>> Csaba
>>
>>
>> On Oct 29, 2008, at 6:05 PM, Ingo Debus wrote:
>>
>>>
>>> Am 28.10.2008 um 21:38 schrieb jpitt at fhcrc.org:
>>>
>>>> Do I have to desolder every single +15 and -15 line off every  
>>>> board  to track down the short or is there an easier way?

jpitt

Yes, you have to. Then measure it board by board. Narrow it down to  
the board. Then measure the caps first. I don't know any other way.

Csaba

>>>>
>>>
>>>
>>> First thing I would do is search for anything that gets hot.   
>>> Careful, the offending component probably gets *very* hot.
>>>
>>> If this doesn't help, I'd take a close look at all tantalum   
>>> capacitors (if there are any). I've seen failed ones that looked   
>>> fine but had just a tiny silver ball (like a solder blob) on them.
>>>
>>> Ingo
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