[sdiy] Test Equipment Repair

[harrybissell]

Hmmm...

Remember that some of the 'older' scopes were built with fewer 'proprietary'
parts and more integration.  So newer is NOT always better in a repair sense.

They also got better at making things CHEAPER (including metric @ssloads of TEK)

in the 90's ... era of the disposable generation of products and the
rise-of-the-BEAN-counters...

I think that most folk who could fix and build synths could also repair scopes,
especially with an 'emergency scope' on hand.  I will admit that I waited ten
years
to fix a blown Telequipment that had only one channel working.  (I was ashamed
that here I am, an engineer with a one channel scope and the service manual in
hand!)

I found the chopper circuit was a weird array of diodes... then realized it was
essentially a DIODE analog switch (just like a ring modulator or diode keying
circuit).
Turned out I needed an GERMANIUM diode... so a 1N60 was pressed into service
and is still working (if a little less well that the original part)

Now how would I have seen that, if not for true synthknowledge !!!

Get a schematic or service manual for it, and look where the burned resistors
are.  When you fix it in a hour or two you will feel three hundred dollars
richer, and
a thousand dollars more confident in your skills.  If it does not pan out...

THEN "WHO it"   :^P

H^) harry

Tom Arnold wrote:

> So, here's what I found out how getting test equipment repaired and
> calibrated.
>
> 1. Its freakin expensive.  $375 was the lowest quote I got for fixing my
> 1522B.
>
> 2. Its hard to find places to do it, but when you do they'll be just about
> next door.  I looked for places for a week and called around, just to find a
> place in South San Francisco about a mile from where I sit right now.
>
> 3. Its cheaper to get a recalibrated newer model used scope then to get an
> older scope repaired.  $300 to get a cleaned/recal'd HP 1525A w/DVM option,
> plus he said he has, I believe the term was "A metric assload" of Tek's he
> can make a deal on.  All 90's vintage unstead of 80's vintage like I have
> now.
>
> So, I may have a free to a good home slightly broken 1522B soon, and a
> really cheap to a good home 100mhz Leader if I dont feel like keeping it for
> an emergency spare...
>
> --
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>  - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org
>  - SynthGeek        -
>  - BBD Fanatic      -  "...is it a virus, a drug, or a religion?"
>  - echo evho wjxo   -    Juanita Shrugs. "What's the difference?"
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