Looking for some help....

[KG4ZPD]

A friend of mine has an ol' Radio Shack Pro-94 TrunkTracker. Problem is is that when turned on, there is nothing displaying. There are new batteries in it, and have tried just about everything I can think of to get it to work. Any advice would be helpful.

 

[N4JNW]

Does it recieve anything at all? Will the WX band come in? If it has no problem recieving, my money's on the display just flat out not working.

 

[gmclam]

Yeah, the first question is does the radio work - can you hear RF noise on any channel (just turn the squelch all the way). If that's the case it could be the CONTRAST adjustment to the display. If you're not hearing anything, then it is not getting power. Try a wall wart for power too.

Good luck

 

[KG4ZPD]

Nope, nothing. All contacts were checked and are in good shape, new batteries, and nothing. Same with using a wall adapter

 

[N4JNW]

So it's not even getting any power... So you've ruled out the fact that it's a power issue. Fresh batteries, no corrosion, and using a wall wart.

Well, that rules out the cheap and easy fixes. Next step would be to open up the scanner, with it plugged into the wall wart, and trace where the voltage is going with a tester.

 

[gmclam]

Scanner power failure

Common places that power fails past what you've already tested.

1. The connection through the power jack. Since both sources fail to power the scanner, it would have to be on the load side of the jack.

2. There is a reverse polarity protection diode in series with the power. It prohibits voltage from flowing when the input polarity is reversed. If the diode opens, no power flows at all.

3. The power switch - on the volume control. It is a mechanical device and more likely to fail than other components.

4. After the above you're dealing with a bad solder joint or a defective component - a voltage regulator or something shorted.

Good luck.

 

[KG4ZPD]

Thanks, let me go ahead and check these ideas out and see what I can find out. Once again, thanks.