|[AMRadio] Progress report on my DX-100|
Bob Bruno - K2KI
k2ki at starc.org
Tue Mar 11 20:52:10 EST 2008
I just thought I would share what I have been doing to the DX-100
transmitter that I got the other day.
The whole radio looks like it was dipped in a nicotine vat and left to sit.
First, I removed the chassis from the enclosure which BTW does not have
any holes drilled in it but it too was brown and sticky.
I noticed right off that the 6AU6 VFO tube was cracked and was white
inside. I then tested all of the tubes and found the 5763 Driver tube
had an open filament. The 12BY7 Xtal Oscillator tube was also bad. My
tube tester (B&K Dynajet 606) does not test 1625's. I have 21 NOS and 5
used but working 1625's so I can replace both without breaking a sweat
I then inspected the topside of the chassis. There are numerous places
where the chassis is rusted. It looks like something dripped down into
the rig. Other than that, a good cleaning will make it shiny-new. The
Final tank will need some attention but not too much.
I then inspected the underside of the beast. It looks just like the day
it come out of the box. All shiny and new. There are a few bad solder
connections and the caps need to be replaced. The .1 MFD 600V cap has a
crack running from one end to the other. The Power Xfrmr was clipped out
of the circuit and reconnected. I would say that it probably died and
was replaced with a Xfrmr from a donor.
Other than the above, all looks extremely promising.
Now to the fun part... The front panel...
I first removed all of the knobs and felt sick just holding them. All of
them were caked with hardened hand oils and nicotine. I couldn't even
scrape them clean. So, I soaked them for about 3 hours in a hot soapy
water mixture with some vinegar mixed in. After I scrubbed them with a
toothbrush, they came absolutely clean. Oops. I think I used the XYL's
toothbrush. Shh don't tell her :-)
While the knobs were soaking, I had at the front panel. The paper towel
that I used for the first pass was brown and stank. It took me 3 hours
to completely clean and degunk the panel.
After reinstalling the knobs, I stepped back and realized that I
actually made progress. Seeing that thing turn from a brown box-shaped
turdlet to a shiny vintage xmitter, made me feel better about the whole
Next installment will be the chassis cleaning and capacitor replacement.
I took pics along the way. I posted them on my Photo Bucket acct. Here
is the link:
Until next time...
Bob de k2ki
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