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Did my palamar die


Palomar?

Not very specific.

1970s Palomar?

or 80s?
90s?
Or is it too young to buy a drink?

Keying circuits can do this. Does the standby switch shut it down? Or the power switch?

Tubes?

Transistors?

Base?

Mobile?

All important clues to zero in on an explanation or a fix.

Kinda like "My Ford won't start".

More than one kind.

73
 
Ok cool. Black face, blue face, 2 pill 4 pill ? I assume heat sink on the top, power switch to the Left, lmh power in middle, pre amp on the right?
 
Hmm. Itty-bitty DIP-package relays. Probably a failed relay. An amplifier that's turned off should act like a barrel connector in the coax. The amplifier's failure to act like a barrel connector suggests this. That amplifier had the mixed blessing of double-sided plate-through circuit board. Makes it more rugged, and more trouble to remove small parts. Each component-lead hole has a metal sleeve in it, to join the top-side foil to the bottom-side foil at each hole. Commonly called a "plate-through". More trouble to desolder. Just wants to stick the pin to the inside surface of that sleeve. Heating the pad repeatedly to extract enough solder risks heat damage to the glue holding the foil pad to the board. Tugging on it can pull the sleeve out of the hole altogether. That relay is best removed destructively. It gets clipped into pieces until only the pins remain where you can grab one of them at a time. Grip each pin from the top, melt the solder from the other side and remove each pin with no stress to that sleeve. The remaining solder will be easier to remove from the empty hole than it was when there was a pin in the hole.

No way to do this without removing the circuit board. No need to unsolder the RF transistors. Just remove the two bolts on each. The one I remember has outer edges of the circuit board captive in a track on each side. Has to slide out. Usually best to unsolder the wire from each coax socket. and slide it out the front. Tricky part is to smear heat-conducting compound onto the heat sink so the transistor doesn't scrape it all off sliding the board back into place after the relay is replaced.

Not fun but doable. It's the only way to find out how much of the rest of the amplifier is dead or alive. Everything goes through that relay, so when it breaks you can't tell what else is or isn't broke.

The original relay is most likely rated at 2 Amps. If you can find it, the 3-Amp version should be a bit more stout. Pretty sure that's the highest Amp rating you'll find in that physical package.

The pin pattern layout is not the same for every relay that size. The replacement relay has to match old relay's pin layout to line up with the holes in the circuit board.

What are the brand name and type number on the top of the relay? Would help to nail down a compatible replacement.

73
 

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