Radio Shack Pro-97 scanner

[ryan74]

This scanner volume does not work. I can hear the National weather frequencies(I use because it is always on) with my ear against the speaker but when I turn the volume knob up or down the volume doesnt change.
I dont know where to start, the volume/squelch knob does not seem damaged and I don't know if/how it can be tested.
I can hear a change in static sound from adjusting squelch(normal) so I assume that part of knob works.
Any advice?

[ryan74]

Re: Radio Shack Pro-97 scanner

I found this at radioreference.com
Quote: There's a known issue with the volume pots on these things going bad. Mine did the same thing right at the one month mark. Question: if you put the speaker right up to your ear can you hear squelch rushing very very faintly as you turn the knob?

Looking at the schematic, there are a few components between the discriminator output and the audio amp. The beep signal is inserted AFTER the volume pot. I agree and think the volume pot is VERY LIKELY the problem.

I found the part number
12429163 from RSU(radioshack unlimited)
It is $16 if it is still avail.

I wouldn't mind an alternative. From what I read it is 50kohm volume and 10kohm squelch.

[ryan74]

Re: Radio Shack Pro-97 scanner

I pulled the pot and volume side tested bad.
Im not sure if I can match up a replacement.
pot # HTA503
U245
B10K
I took measurments the best I could and posted on pic.

[ryan74]

Re: Radio Shack Pro-97 scanner

I decided not to fix after finding out analog scanners will be obsolete soon with the digital switch. Plus the part is out of stock.

[ratdude747]

Re: Radio Shack Pro-97 scanner

I decided not to fix after finding out analog scanners will be obsolete soon with the digital switch. Plus the part is out of stock.

Yeah... It's a bummer. My scanner already is useless (a nice digital controlled one I might add). I can't pick up any emergency channels.

[imp]

Re: Radio Shack Pro-97 scanner

Please note that you also have at least one bad capacitor on the board (first picture, lower right corner)