S-Meter not working

Dino_24 · Post by **Dino_24** » Saturday 29th Nov 2008, 15:35

Tried a 2sc1969 final in a cobra 29/nw/st and when i keyed up, it pegged the s-meter until it got stuck.... even when i adjusted VR5. also it showed very high SWR. So I just said screw it and put an irf520 in and it transmits fine. Now the S-Meter doesn't work at all.... even on receive.

What should I check?????

http://www.youtube.com/user/TheDefpom · Post by **The Defpom** » Saturday 29th Nov 2008, 15:42

is it stuck at minimum or maximum scale ?

Dino_24 · Post by **Dino_24** » Sunday 30th Nov 2008, 4:54

Its stuck at minimum scale. Thanks.

Rick · Post by **Rick** » Sunday 30th Nov 2008, 8:58

Check the meter with a DVM on a diode test, and the meter should move.
If the meter is ok then check you do not a cold solder joint or broken wire.
If all is ok check the components, I would tell which components to check but you have not given the PCB number.

It maybe a good idea to read www.radiomods.co.nz/forum/viewtopic.php?t=312
Before you do any more posting.

Dino_24 · Post by **Dino_24** » Sunday 30th Nov 2008, 9:21

Okay... sorry about that.

As I mentioned, it is a Cobra 29/NW/ST. As for the PCB number, the only one I was able to find is KEPC-225D. I'm guessing this is probably it. As for the PLL... I'm new to CB repair and I'm still learning, so I haven't a clue where it is. I'm guessing it is one of the verticle mounted, flat IC's.

I tested the meter and it works. So it must be the circuit.

Rick · Post by **Rick** » Sunday 30th Nov 2008, 9:43

The KEPC-225D is the PCB number, the PLL is at the front of the radio near the channel switch and will have a number like uPD2816.

As the S/RF meter is not working in RX and TX, would suggest that you have a common wire broken or you have the SWR/CAL switch in the in the SWR or CAL position and not in the S/RF position, this is easy to do, I have seen a quit a few people do this.

Check the switch is in the right position and the wiring to the switch and PCB.

Dino_24 · Post by **Dino_24** » Sunday 30th Nov 2008, 11:44

Found it! It was just a broken wire to the switch.... how'd I miss that???

Thanks for the help, Rick.