[sdiy] SCI Pro One 15+ power rail

[Tom Wiltshire]

Not a bad idea anyway. I replaced the regulators and power caps on my Pro-One as a preventative measure. The poor things are 30 years old - that's got to be the end of their designed lifespan.

On 28 Aug 2013, at 08:51, Stewart Pye <stewpye at optusnet.com.au> wrote:

> Csaba,
> 
> I thought you discovered there is no short on the +15V output???
> Is the regulator getting hot?
> 
> In my experience most shorts on power supply lines will measure a short when tested with a multimeter on DC resistance. There has been the odd occasion when it has been within an IC and didn't show up until power was applied. It's cheap and easy to replace a 7815, rather than chasing ghosts.
> 
> Regards,
> Stewart.
> 
> 
> On 8/28/2013 7:38 AM, Csaba Zvekan wrote:
>> Barry,
>> 
>> Could I be using my FOSCAM Baby monitor in infrared mode to find and see the possible bad cap ?
>> 
>> 
>> On 27 Aug 2013, at 23:33, Barry Klein <Barry.L.Klein at wdc.com> wrote:
>> 
>>> Just found a shorted multilayer ceramic this way on a server board last week. Took 30 seconds.
>>> What, you don't have an IR camera?  One coming on Indiegogo for $150....   :-)
>>> 
>>> -----Original Message-----
>>> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Tony Kalomiris
>>> Sent: Tuesday, August 27, 2013 1:53 PM
>>> To: Synth DIY
>>> Subject: Re: [sdiy] SCI Pro One 15+ power rail
>>> 
>>> You could try replacing the 15 V regulator, seeing you replaced the tantalums already.
>>> Or isolate the PSU from the rest of the electronics to know if something is shorting out.
>>> Touch the regulator to see if it's getting hot. is the +5 V ok, it's fed from the same full wave rectifier.
>>> You didn't say what the input voltage was at.
>>> 
>>> I like Barry Klein's suggestion, for people with a well equipped bench.
>>> IR camera eh ? hmm
>>> 
>>> Tony K
>>> 
>>> 
>>>> On 8/28/2013 6:37 AM, Csaba Zvekan wrote:
>>>>> HI John ,
>>>>> 
>>>>> All the tantalum caps have been replaced by electrolytics. I also removed all the socketed IC's hoping that the voltage comes back to +15V.  Now I will measure OP-AMPS power and see if I have a low resistance.
>>>>> Can I do the same with the CEM3310 and CEM 3320. And most of all can I do it in circuit ? I could go ahead and socket and replace all new OP-AMPS I'm still guessing that's not my problem.
>>>>> I'll double check the bypass caps again.
>>>>> 
>>>>> Csaba
>>>>> 
>>>>> 
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