Uniden 2830 crazy meter

[NightProwler]

Digging through my junk cupboard the other day I came across my old Uniden 2830 in bits. I replaced the outputs as they were fried and done a few other jobs to it and got it working apart from the signal meter which always reads S6 even with no antenna connected. After a bit of searching I came across this...

https://www.vintage-radio.net/forum/sho ... p?t=138594

I followed what to replace in the AGC area which was the caps, They looked ok but I changed them anyway but the radio is still doing it. When first turned on the signal meter reads S0 then it slowly rises to S6, It's acting weird on TX too.

Anyone got any ideas before I chuck it back in the junk draw?

Cheers all...Rich

[cb4ever104]

The key tests on that other post Rich are the voltage ones .

"Ideally you need to check/clarify the AGC level at IC101 pin 14 when it is misbehaving. What DC voltage does it show at pin 14 when there is a dummy load on the antenna port and it is still showing S5 on the s meter? If you can get it to behave like this then check at pin 14 on all modes AM, FM and SSB when the s meter is reading a false high.

Note that +105mV is the approx reading I'd expect at pin 14 on a healthy radio with a dummy load on the antenna port and nothing showing on the s meter."

What have you got Rich ?

[NightProwler]

I havent checked IC101 yet but I shall check tonight if I got time.

[cb4ever104]

It's acting weird on TX too.

Is the PLL section all OK ?

[NightProwler]

It's working fine on TX and RX. Put on a frequency counter and all is fine. Just the meter is crazy.

[cb4ever104]

Probably not the AGC cct then if it's happening on TX . Saying that I'd still check those voltages on IC101 .

[NightProwler]

I havent had time tonight as I have been building a 15M dipole. I will check the voltages on IC101 when I get chance but if it's not that what could it be?

[cb4ever104]

What does the meter do on TX ?

[NightProwler]

It stays around S6 to S8 even on SSB.

[cb4ever104]

It stays around S6 to S8 even on SSB.

Hi Rich . Does it go above this level on TX when you whistle for example , or does it just stay at between 6 and 8 regardless . Also . Does the modulation meter work ?

[Otter]

I think that the SWR cal pot is broken, or has lost its ground connection. I know it's not an SWR issue, but the pot is part of a potential divider for the meter circuit for all functions.

[NightProwler]

Tried it again just now. Dummy load plugged in, Turn the radio on and it's at S0 then slowly rises to S6. TX on SSB and it sits at S6, A quick whistle at it bounces up to S9 then drops down to S6 again.

[NightProwler]

Ahhh funny you should say that because the SWR pot fell to bits and is no longer there. Aha might be on to something here

[cb4ever104]

the pot is part of a potential divider for the meter circuit for all functions.

Thanks for that Tim . I was having fun looking around Q311 , but you seem to have nailed it

[NightProwler]

Just took it apart again and where the SWR pot is soldered in the switch PCB on the front, It has broken away from it and fallen to bits. So I figure I can just fit in another pot

Watch this space.