Thread: 1969 Delco Car Radio Saga
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Michael A. Terrell Michael A. Terrell is offline
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Default 1969 Delco Car Radio Saga

wrote:

Had some boards at work with 'lytic caps leaking acid. SWMBO said no way bringing them home. Company bought a dishwasher explicitly for electronics cleaning and it works very well. I use a small amount of detergent, no active drying in the dishwasher but we also have a commercial food dehydrator for 'baking' tapes. 17 hours at 125F makes the boards look and work like new again.


We used a citrus based solvent in an industrial circuit board washer
at the Microdyne plant in Ocala, Florida. I don't remember the brand,
but it was a modified restaurant type dishwasher that sat on top of a
stainless steel tank that held the solvent. The modifications were that
tank, and an additional pump to circulate the solvent between the rinse
stages. That cut the cleaning costs, and also trapped any parts that
came off of new boards due to problems in the reflow oven. It had over a
dozen solid state relays added, for the modified wash cycle.


Most of those early Delco solid state radios were a breeze to fix.
Most spent less than 10 minutes on the bench, since the biggest failures
in the '70s & '80s were open RF/IF transistors, or a shorted output
transistor. They failed so often that the radio bench had its own
inventory of parts right above the test equipment. It often took longer
to do the paperwork than the actual repairs.

A curved hemostat, and clipping the leads to different lengths let
you replace the RF transistors without removing the circuit board from
the tuner. That trick alone, cut about 15 minutes from each repair. The
first shop would remove the board, and quite often they would break the
tabs off the coils and then they would wait for a new tuner to be
ordered.
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