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Most common faulty part in old electronic gear

Regarding this kind of switch:

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When it comes to working on old electronic gear from the 1950s thru 70s or 80s I keep reading the most common fault are the old paper/wax capacitors and electrolytics.

While there is truth to this in some cases, I have found a part that fails about 90% of the time on these old devices. They are these old slide switches (shown above). I just picked up an old Sencor Substitutor box from the 50s or 60s. The caps and resistors are not looking to be bad, but all three of the slide switches are junk. Even after sliding them back and forth 100 or more times, they are erratic at best, or dont work at all. (I am awaiting a can of Deoxit from an online order, since I can not buy it locally). I have my doubts that even this stuff will fix these switches.

Do they make more reliable replacements for this type of switch that will fit the same holes? Heck, even in the 70's when they were only a few years old, these switches were troublesome.

I never understood the reason for gold plated speaker terminals, but these switches should be gold plated, or something done to them, since they were always faulty.

Reply to
oldschool
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Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

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void _-void-_ in the obvious place

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Reply to
Boris Mohar

Oh, yes! Those old stamped metal slide switches with the phenolic wafer with the contacts in it were quite awful, and had a short life before they started getting flaky contacts. It might be partly the open nature of the switch, lets lots of air get to the contacts. I just repaced some pretty decent PCB mounted push-push switches that were a definite cut above the cheap ones, but still had a sliding contact spring. But, air and maybe loss of lube had caused the contacts to deteriorate. Exercising the switches just made them worse. This was on 36-year old scientific equipment.

Jon

Reply to
Jon Elson

A lot of this has to do with location and storage. I have a lot of Dynaco a udio stuff - and David Hafler was notorious for using low-bid/surplus/salva ge and "seconds" stuff - that are generally pretty much fine as they have n ever seen damp, a garage, or unconditioned space in their 38 - 57 year hist ories. I have a number of vintage radios (TransOceanics) that are up to 30 years older that are also pretty good - as Zenith went at least one step up in initial quality. These switches get flushed before first use in any cas e.

But rotary and pot switches are a different story. Those I have had to lear n to restore and/or rebuild. A PITA, but there are usually only a few bits inside to go bad.

As to caps - unless they are potted or PIO caps, I do not even bother - the y get replaced out-of-hand. It is not a matter of "if" but "when".

Enjoy!

Peter Wieck Melrose Park, PA

Reply to
pfjw

And:

There are kits out there for restorers:

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Peter Wieck Melrose Park, PA

Reply to
pfjw

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