1969 Delco Car Radio Saga

pf...@aol.com

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Mar 10, 2016, 8:46:24 AM3/10/16

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This might be of interest to some. My neighbor down the block is restoring a 1969 GM pick-up truck, and brought me the vintage radio from it to see if I could do anything with it. He had *NO* interest in converting to FM, much less stereo, all he wanted was to get the AM back.

The radio looked like it had been ridden hard and put away wet each and every day since 1969, fully encrusted with filth, grease, what looked like melted sugar, plastic and more. To the point where the tuning knob was locked, as were the preset buttons. This is a solid-state radio, not tube, of course.

I took the attitude of kill or cure, so after partial dis-assembly, removing the top and knobs, I put it on the top shelf of the dishwasher (Bosch) and ran it through a full scrub cycle (alone), then dried it in the oven for 2 hours at 175F. It came out sparkling clean, and with (thankfully) the back-painted numbers on the dial intact.

NOTE: Do not try this with dishwashers that have exposed heating/drying elements. They get too hot in some cases.

Applied power and got hiss. Check the 4-section cap, ESR was good, but by resistance, two of the internal sections were shorted such that capacitance was high, but they were, effectively, the same cap. I replaced the entirety with new caps rated slightly higher in capacitance, twice the voltage.

Applied power into a very inefficient speakers and got HUMMM - under a fluorescent shop light.

Installed an antenna - got reception across the band. This is the 6th bit of electronics I have put through the dishwasher. Two Zenith TransOceanics, one Dynaco FM5 tuner, one Dynaco PAT4 pre-amp and one other US tuner. Haven't lost a patient yet.

Don't be afraid to take heroic measures if the alternative is landfill.

Peter Wieck
Melrose Park, PA

John-Del

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Mar 10, 2016, 10:50:25 AM3/10/16

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And here I thought that dishwashers were made for steaming fish..

Did you use standard dishwasher detergent or something else?

N_Cook

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Mar 10, 2016, 11:05:41 AM3/10/16

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Was SWMBO around at the time?

pf...@aol.com

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Mar 10, 2016, 11:50:10 AM3/10/16

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On Thursday, March 10, 2016 at 10:50:25 AM UTC-5, John-Del wrote:

> And here I thought that dishwashers were made for steaming fish..

Not so much on a Bosch. There is no exposed heating element, so the water never gets to more than 180F, and then only during the actual washing cycle. The drying cycle uses residual heat and fan-forced air. So, the water is heated directly, not the entire inside of the dishwasher, and there is nothing other than the fan blowing during the drying cycle.

>
> Did you use standard dishwasher detergent or something else?

Standard high-phosphorus/bleach detergent, yes. We are on a municipal sewer system, so I do not worry about phosphorus discharge. Normally (and this is normal?) I use no detergent at all. But this unit was beyond merely filthy - the heat-sink fins were indistinguishable, that bad.

My wife is not at all squeamish about this sort of thing, I have cleaned/restored stuff for her that she thought was entirely unsalvageable. The dishwasher has a stainless steel inside, the oven is actually self-cleaning, and there were no untoward smells. She sees it as another demonstration that I am 'handy' to have around.

Ian Field

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Mar 10, 2016, 5:35:51 PM3/10/16

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"John-Del" <ohg...@aol.com> wrote in message
news:c32cfb38-4185-4f0a...@googlegroups.com...

Apparently you can cook fish fingers in the toaster.

Ian Field

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Mar 10, 2016, 5:37:29 PM3/10/16

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<pf...@aol.com> wrote in message
news:899d1ae0-a6ec-48c2...@googlegroups.com...

> This might be of interest to some. My neighbor down the block is restoring
> a 1969 GM pick-up truck, and brought me the vintage radio from it to see
> if I could do anything with it. He had *NO* interest in converting to FM,
> much less stereo, all he wanted was to get the AM back.
>
> The radio looked like it had been ridden hard and put away wet each and
> every day since 1969, fully encrusted with filth, grease, what looked like
> melted sugar, plastic and more. To the point where the tuning knob was
> locked, as were the preset buttons. This is a solid-state radio, not tube,
> of course.
>
> I took the attitude of kill or cure, so after partial dis-assembly,
> removing the top and knobs, I put it on the top shelf of the dishwasher
> (Bosch) and ran it through a full scrub cycle (alone), then dried it in
> the oven for 2 hours at 175F. It came out sparkling clean, and with
> (thankfully) the back-painted numbers on the dial intact.

What's that in Centigrade - apparently germanium transistors brew up
somewhere around water boiling point.

Clifford Heath

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Mar 10, 2016, 5:42:31 PM3/10/16

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Boiling point is 220F.

Nice story :)

Phil Hobbs

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Mar 10, 2016, 6:00:37 PM3/10/16

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Where do you live, the bottom of a lake? 212F at 1 bar!

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

DaveC

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Mar 10, 2016, 7:11:00 PM3/10/16

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> Boiling point is 220F.

http://www.engineeringtoolbox.com/boiling-points-water-altitude-d_1344.html

Clifford Heath

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Mar 10, 2016, 9:37:11 PM3/10/16

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Sorry, that was a typo. At least know I was *thinking* 212... as the
engineer arrived to certify our new footings..

pf...@aol.com

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Mar 11, 2016, 8:10:14 AM3/11/16

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On Thursday, March 10, 2016 at 5:37:29 PM UTC-5, Ian Field wrote:

> What's that in Centigrade - apparently germanium transistors brew up
> somewhere around water boiling point.

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=fahrenheit%20to%20celsius

175F = 79.444C
180F = 82.222C

captainvi...@gmail.com

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Mar 15, 2016, 5:05:22 PM3/15/16

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On Thursday, March 10, 2016 at 8:46:24 AM UTC-5, pf...@aol.com wrote:

Fish fingers must be very small. Do you eat them by the gross or the ounce? Lenny

stra...@yahoo.com

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Mar 20, 2016, 6:22:18 PM3/20/16

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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.

G²

Ian Field

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Mar 21, 2016, 2:59:43 PM3/21/16

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<stra...@yahoo.com> wrote in message
news:5392a777-ddde-4248...@googlegroups.com...

Boards have had water soluble flux since they banned the solvents to protect
the ozone layer.

AFAIK: all PCBs are cleaned in water nowadays.

captainvi...@gmail.com

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Mar 21, 2016, 5:34:57 PM3/21/16

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On Thursday, March 10, 2016 at 8:46:24 AM UTC-5, pf...@aol.com wrote:

> Melrose Park, PA?
I have alot of music on reel to reel. some of the oxide comes off of some of these. I know that their days are numbered. Can I save them? thanks Lenny

What' the deal on baking tapess

MJC

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Mar 21, 2016, 7:01:51 PM3/21/16

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In article <5392a777-ddde-4248...@googlegroups.com>,
stra...@yahoo.com says...

Reminds me of the "best butter" used by the March Hare in his watch, as
told by Lewis Carroll!

Mike.

Michael A. Terrell

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Mar 27, 2016, 4:40:18 PM3/27/16

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stra...@yahoo.com 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.

Michael A. Terrell

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Mar 27, 2016, 4:41:55 PM3/27/16

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captainvi...@gmail.com wrote:
>
> I have alot of music on reel to reel. some of the oxide comes off of some of these. I know that their days are numbered. Can I save them? thanks Lenny
>
> What' the deal on baking tapess

That depends on the backing used. Acetate requires a different
method than mylar.

DaveC

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Mar 27, 2016, 6:04:10 PM3/27/16

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> I have alot of music on reel to reel. some of the oxide comes off of some of
> these. I know that their days are numbered. Can I save them? thanks Lenny
>
> What' the deal on baking tapess

Not nice to hijack a thread.

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