Chassis Cleaning

[Greg Gore]

The handiest tip I ever received to clean really dirty chassis and dirty
crackle cabinet paint finishes was to keep a 50% mix of Ammonia and 409 in a
plastic sprayer bottle and distilled water in another sprayer bottle for
rinsing and use an assortment of brushes including different size paint
brushes and tooth brushes. Be sure to wrap some tape around the metal band on
the brushes or it will scratch aluminum IF cans and other soft metal parts. I
start by completely disassembling a set as much as possible organizing the
hardware in muffin trays. Then I tape plastic bags around sensitive parts
like transformers. The transformer laminations will soak up water like a
sponge and it is impossible to get them dry again without boiling them in
paraffin wax (when the wax stops bubbling you are dry). The transformer will
eventually blow if it gets wet inside and you don't get it dry. I tilt the
chassis on an angle to promote run-off on an old card table on the deck out
back and with a towel or plenty of rags at hand and with the sprayer bottles
and brushes I wash the chassis carefully watching where the water is going
and blow dry with a shop vacuum as soon as possible when I am finished
rinsing. Afterwards I leave it out in the hot midday sun to allow it to
finish drying completely. Sometimes I put the chassis on my air conditioner
condenser outside so that the strong hot discharge air from the fan will help
ensure the set gets dry. Be careful with silk screened nomenclature, logos
and witness marks and especially dials and dial glasses as ammonia will
dissolve the printing on most of them. Test any cleaning agent first before
it's too late. Use a milder detergent if in doubt. Another caution would be
for the ink markings sometimes found on chassis for tube socket ID and
production run identifying marks. Ammonia will attack them too. If the
chassis is cadmium plated and the appearance still needs more work I finish
up with a little polishing with a metal polish called Blue Magic buffing to a
bit of brilliance to restore appearance. Be careful and use it sparingly as
it will easily get in the tube sockets and other hard to remove places and if
it does you might want to wash the chassis again. I generally wait about a
week before powering up again but then it usually takes me that long to get
the set back together again anyway. I only use this method on the really
dirty ones. Many times all you need to do is take the set apart and blow the
dust off with your shop vac with a little help from your brush collection and
maybe supplement that with Q-tips, alcohol and Windex. This would be a good
time to apply lubricants (sparingly) to working parts to restore smooth
control operation remembering a radio is 50% mechanical construction as well
as 50% electrical. Get ready for reassembly by cleaning all the hardware and
polishing the knobs.

Regards, Greg Gore; WA1KBQ

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