Re: Re: Omega Race repair

Zonn wrote:
> On Thu, 12 Oct 2006 07:23:32 +0400, peter jones <highwayman2000@mail.ru> wrote:
>
>
>> -----Original Message-----
>> From: "simon" <simonjhanlon@btopenworld.com>
>> To: <vectorlist@vectorlist.org>
>> Date: Wed, 11 Oct 2006 23:07:04 +0100
>> Subject: VECTOR: Omega Race repair
>>
>>
>>> Today I thought it was time I fixed my Omega Race, I have a few spare boards for it, most with some acid damaged. I found one that was fairly clean and replaced the 2 ram sockets near the battery. On power up the + and - 15v regulators were getting too hot to touch, I checked between the 2 and had a reading of 35 ohms between the-15 and 15v lines. I suspected one of the Op amps or a DAC was to blame. After pulling 3 of the 4 Op amps I found the bad one,
>>>
>> couldnt you find the bad one by burning your finger on it?
>> that works pretty good with dram a lot of the time.
>>
>
> That's a good point!
>
> I'll bet one of those infra-red temperature pointer thingies would work well in
> spotting parts that are overheating. You know, after you've burned away the
> nerve endings on your 10th finger...
>
> >From the ad at the top of Google:
>
> http://www.testequipmentdepot.com/newequipment/irthermometers.htm?gclid=CI3fptHX8ocCFQU8YQodskxUjQ
>
> -Zonn

Or just finally get a much better ohmmeter.
At my Real Job I have an HP 34401 multimeter. A use it for finding
which one of 19 paralleled capacitors is shorted. I put it in the 20
ohm range, select 6-digit mode (measuring 1/10 of a milliohm), and it
has a min/max mode. With all that going all you have to do is probe
each part---the last one that makes it beep (because it was the lowest
reading) is the shorted part. Too bad it costs several hundred dollars
for one of those.

A much cheaper way would be to clip your meter across the two power
supplies and spray one part at a time with freeze mist. Whichever part
gives you the largest resistance change is the shorted part. (That's
too simple, can't possibly work---or can it?)

Or, if you can't even afford a meter there is another simple way. Frost
up all the parts in question and turn it on. The first one to defrost
is the bad one.

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Received on Thu Oct 12 04:40:17 2006