HR-2510 no AM receive:

[steve94560]

Howdy, I've got a good functioning HR-2510 everything works except that I had the radio put away for some months and I recently hooked it up and noticed that the AM receive has no audio. It transmits AM fine and SSB and FM ok, just no AM receive audio. Is there a way to bleed off the capacitor that holds the memory to the CPU of this radio. It is stock with no chipswitch. I'd like to get on 29 Mhz AM but it's not possible. SSB works great though.

Also if I was to ship to a radio repair center does anyone have a referral that works on these old guys?

thanks and 73's de Steve

 

[TheMadScanner]

Hey Steve, Oddly enough, I just had the same thing happen with my Lincoln recently. I've pinpointed a few components that may be causing it but haven't received replacements yet. Have you gotten anywhere with figuring out what is causing yours to do this yet?

Steve

 

[steve94560]

Uniden HR-2510 no AM recieve:

Howdy, I am suspecting that it's a glitch in the processor. There is something that stores the last frequency used when the radio is turned off. I'm thinking it's a capacitor rather than a battery. I am shelving the radio for about a month and then I will re visit. It's a great radio and I like the continuous coverage. I never had a chipswitch for the rig. I also thought I might try to find the capacitor holding the settings and put a ground on it to clear the memory. In the research that I have done on this radio there does not appear to be a reset sequence or reset button. It's strange too as SSB works fine on receive and so does CW. I'm thinking the radio will work fine once I get it reset. I'll let you know if I find anything out.

Steve in Calif.

 

[TheMadScanner]

Found it Finally...

Hey Steve, I finally had a chance to sit down and tinker with mine and it appears that the 2 47uf electrolytic caps that are connected negative to negative were both leaking voltage to pin 14 of the AGC IC in AM and FM modes only.

My AGC voltage was in the 5 to 6V range without any received signal at all on AM and FM. Other modes were OK. This killed the receive and even gave me a phantom S Meter reading of S4 to S6.

I removed the caps feeding the voltage to the IC and the receive came back to normal. I replaced the 2 47uf back to back caps with a non polarized 22uf 16V cap and all was well once again. There is also a diode used in this circuit but mine tested good so I left it alone.

My 2600 isn't doing this yet but I am going to go ahead and replace the AGC caps in it as well to prevent it from crapping out on me in the immediate future.

If you haven't already, give it a shot and see. I'm almost certain that this is the same thing going on with your radio.

Steve

 

[hammer103]

steve

hey can u post a pic where the 2 caps are i have two 2510s doing this

 

[TheMadScanner]

I don't have either of those 2 rigs anymore so I can't take any pics of them. If I remember right, they are pretty easy to spot but I couldn't tell you where they were.

There's also a chance that someone may have done the same thing I had so you might not have 2 caps.

Your best bet is to check out the schematic and test your AGC voltages on pin 14 of IC101. You should have very low voltage ( <1VDC) when you're not receiving anything and it should become more positive as you do receive a signal.

The attached image is taken from the schematic and it is the area that you want to focus on.

 

[Delta33]

Howdy, I've got a good functioning HR-2510 everything works except that I had the radio put away for some months and I recently hooked it up and noticed that the AM receive has no audio. It transmits AM fine and SSB and FM ok, just no AM receive audio. Is there a way to bleed off the capacitor that holds the memory to the CPU of this radio. It is stock with no chipswitch. I'd like to get on 29 Mhz AM but it's not possible. SSB works great though.

Also if I was to ship to a radio repair center does anyone have a referral that works on these old guys?

thanks and 73's de Steve

Why did you post this in the cb forum? The HR2510 is a 10 meter ham radio.