readers are sharp!
Reading our tip about eliminating battery corrosion, a
number of readers looked closely and saw that the corroded batteries were not
carbon-zinc or lead-acid.
Longtime San Francisco market engineer Bill Ruck writes that
baking soda is the traditional choice to clean corroded batteries, but only for
carbon-zinc or lead-acid types. These have an acid electrolyte, neutralized by
the alkalinity of the baking soda.
NiCad and manganese dioxide batteries have an alkaline
electrolyte (and thus are called alkaline batteries). Although baking soda will
work, the fastest way to clean up corrosion here is with a diluted acid.
Vinegar fits the bill. The cheap stuff works fine; Bill says
he wouldn’t waste his balsamic on such a task. (For a list of things you can
clean with white distilled vinegar, see tinyurl.com/wbvinegar2.)
If you can isolate the battery compartment, just pour some
vinegar and then scrub with the toothbrush. If there’s a chance the vinegar may
get on other components — for instance, if the battery compartment cannot be
separated from the equipment — apply with a cotton swab. This takes longer but
you end up with nice shiny clean contact terminals.
Whether you use baking soda or vinegar, clean the contacts
with fresh water, and dry thoroughly.
Fig. 1: This is one of two sockets to be rebuilt.
* * *
I missed Leon Amstutz, CBRTE, at the recent Indiana
Broadcasters Association Annual IT/Engineer Workshop.
Leon is with Taylor University in Upland, Ind. As with
Bill’s cautions, Leon sent me a note about the vinegar and alkaline battery
corrosion problem (he prefers white vinegar).
After cleaning up corrosion debris that had spilled onto a
printed circuit board, he coated the damaged portion of the board with clear
fingernail polish. This resealed it against future spills.
Bill is part of a group that is tackling component corrosion
head on …
* * *
Fig. 2: The RCA T3 PA cabinet.
… as part of a group of engineers who are refurbishing an
old RCA T3 transmitter. This is a 20 kW HF model. The sockets had to be
completely disassembled and rebuilt, as seen in Fig. 1.
After a good soaking in ammonia, things looked a lot better.
Just as vinegar works wonders on battery corrosion, ammonia helps you overcome
salt air’s corrosive effect on silver-plated parts.
round cylinders around the perimeter of the socket; they are actually screen
bypass capacitors! The end caps on the capacitors were so rusted that they were
replaced with new ceramic caps and hardware, to make things fit and sparkle.
Fig. 2 shows Bill next to the PA assembly. Several panels
were removed to facilitate cleaning. What a beautiful result when everything is
completed. Everything was stripped from the transmitter, down to the bare metal
Fig. 3: LEDs, top, provide
a quick visual indication to identify which transmitter is ‘on the air.’
* * *
neat tip that doesn’t cost a lot of money.
times have you rushed to your RF site after a failure, only to find both
transmitters running, one into the antenna and one into the dummy load? It
takes a moment to figure out what’s going on, doesn’t it?
Media Boston has a simple yet effective solution, seen at the top of Fig. 3.
The string of green LEDs gives you a quick visual indication as to which
transmitter actually is on the air.
Workbench. You’ll help your fellow engineers, and qualify for SBE
recertification credit. Send Workbench tips to email@example.com. Fax to
Author John Bisset has
spent 43 years in the broadcasting industry, and is still learning. He is SBE
Certified and is a past recipient of the SBE’s Educator of the Year Award.