555
Ratchet Jaw
Posts: 68
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Post by 555 on Jan 29, 2012 22:05:32 GMT -5
after all these years my luck the freq counter clock all went out what would be a cause of this other than its age
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Post by 2600 on Jan 30, 2012 0:47:42 GMT -5
Age is about the only cause of failure in a counter display that's probably 25 or more years old.
Pinning it down any closer than that begins with the symptom or symptoms you see.
By "out", do you mean that it just won't light up at all any more?
That would be a rare one. Most failures involve a "wrong" reading of several different common types.
My favorite of all the "age" failures in that unit would be loud buzzing sounds in the receiver audio, that change and pulsate every time the digits change. That one is fixed by replacing every electrolytic capacitor on the clock/counter board. Erratic readings that never settle down can be caused by that problem, too.
The first few years the radio was produced, it was common to see failure of the no-loinger-available TC5032 chip. Radios made after 1983 or 1984 will see fewer of those going bad. One or both of the FET transistors that amplify each signal input on the two thin gray shielded wires can fail. Pulling or replacing the plug with those two wires should ONLY happen with the AC plug is pulled out of the wall. Pulling that plug with the line cord still plugged into the wall can blow them out. Next after that would be smaller chips in the counter's input section.
Troubleshooting by the symptom alone is not always easy. A tricky breakdown would call for an o-'scope to troubleshoot.
But any time something that's 30 years old just goes sour, how can it not be "age"?
73
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555
Ratchet Jaw
Posts: 68
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Post by 555 on Jan 31, 2012 14:03:33 GMT -5
the counter just went out turned it on the other morning and everything working good then went got a Dr. Pepper came back and counter and clock all is gone pushed all the push buttons and nothing
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Post by 2600 on Feb 2, 2012 0:44:21 GMT -5
It's been a long while since the last time I saw that failure.
TR522, a power transistor bolted to the inside-rear of the module would be the place to look first. It's the main voltage regulator. TR519 is next to it, and could also shut things down. Don't think that one will make it go totally dark by itself.
Just remember that the pc board in that module is different from the rest of the radio. It's a double-sided board, and has metal sleeves lining most of the holes in the board. They serve to connect the foil on one side to the foil on the other side. They are easy to damage when removing a component lead.
73
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