Long before I joined this list, I remember hearing about Tektronix' washing
the older scopes. I can remember doing calibrations on some of them and
many had several HV supplies, so it's common sense that you would remove
those before washing.
One guy I worked with worked in Oregon and they used to wash them there,
too.
I actually washed a Swan 250 in the dishwasher once, using alconox and, of
course, thoroughly drying it afterward. Yes, it was a bare chassis - that
detergent would probably have a bad effect on silkscreened front panels.
The rig came out squeaky-clean and worked fine (I do recall replacing the
audio output transformer).
Tonight, I wire-brushed the rust off the R-4B chassis and painted over the
nastiness with copper paint. Looks bad close-up, but looks better than the
corrosion that it covers and will blend in with the chassis when the cover
is back on. When you get one like this, it's not a museum piece anymore
anyway, so you work at making a nice "user" piece (tool collectors and users
do the same sort of thing). Yes, if it was an SX-88 or a 1A, I would leave
it as-is, but it's not an SX-88 or a 1A.
I also took apart the PBT, cleaned and re-greased it, and cleaned the PTO
and re-oiled it. There was a lot of sludge in the bearing race and all over
the Nylon gear. Once the sludge was removed, I discovered some end-play and
it reminded me of how we used to really over-grease our ball joints on our
cars when I was a lad to try and fool the inspectors.
This receiver should be ready for alignment by the weekend.
73,
Steve Wedge, W1ES/4
I swear by my life, and my love of it, that I will never live for the sake
of another man, nor ask another man to live for mine.
-Ayn Rand.
All my computers have my signature with various pearls of wisdom appended
thereto.
--------------------------------------------------
From: "Richard Knoppow" <1oldle...@ix.netcom.com>
Sent: Thursday, December 01, 2011 4:50 PM
To: "John Hudson" <john.hud...@calema.ca.gov>; <anc...@ec.rr.com>;
<w1es1...@earthlink.net>
Cc: <captc...@flash.net>; <drakelist@zerobeat.net>
Subject: Re: [Drakelist] Baked Drakes
----- Original Message -----
From: "John Hudson" <john.hud...@calema.ca.gov>
To: <anc...@ec.rr.com>; <w1es1...@earthlink.net>
Cc: <captc...@flash.net>; <drakelist@zerobeat.net>
Sent: Thursday, December 01, 2011 12:14 PM
Subject: Re: [Drakelist] Baked Drakes
As we all know this has been a hot topic many times on the list. One of
my good friends worked at HP Fullerton cleaning, repairing, and aligning
test equipment. The process was, as described prior, blowing out dust,
removing whose items that water would damage, using a solution of simple
green under pressure washer, scrubbing with brush as needed, then
rinsing with distilled water, air hose, and baking at heat under 200
degrees for a week. He said transformers were not a problem for this
process.
It would be awesome to find photo's or documentation of this process and
placed in our document files.
We never had any documentation, just something handed down. I worked
for Neeley Sales Division which became the Fullerton office later. We used
dishwashing detergent but Simple Green might work better. The transformers
and chokes we had trouble with were curiously enough the hermetically
sealed ones. That was because the sealing was often not intact so that a
little moisture could get in. It would be very difficult to get it out
again and it, or perhaps the detergent, would cause arcing and loss of the
device. Those transformers and chokes were removed before cleaning. Open
frame units would dry out fine and were not a problem. We removed meters
and some plastic parts although the drying oven was not hot enough to
damage most plastic. A thorough rinse is important as is blowing out the
excess moisture with filtered compressed air. Filtered because many air
compressors leave some oil residue in the air. Lubrication when necessary
was done to factory specs but I have forgotten what was used, probably
something gotten from -hp- rather than locally. While I went to training
classes at Palo Alto and spent some time at the microwave division factory
I never visited the repair shop there so I don't know what procedures they
used.
We also painted cabinets when required. Note that older cabinets
were painted in whatever the current color was so that you will find older
instruments that originally came with the dark gray cabinets painted in
the almost violet lighter gray or even blue.
--
Richard Knoppow
Los Angeles
WB6KBL
dickb...@ix.netcom.com
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