Hr 2510

[eyecue]

I picked up a couple of President HR 2510's. One is unmolested except for the 11m mod. It is WAY off frequency and the alignment wont bring it in. The PLL voltage is off by about 3 volts and the frequency is unstable. Any ideas are welcome. The regulators on the synth board are pretty close to the proper voltage. That little Tantalum by the PLL maybe? Also the S meter is showing No activity on ANY mode

[MDYoungblood]

The easy question first, meter is probably just stuck, I’ve seen tech’s remove them then shock it with a 9v battery getup, think you might find a YT doing it. Off frequency, I would change out the cap, possibly the problem and by all means check all the diodes in the circuit. Best I can suggest without seeing it on my bench (when I get a new place that is).

3’s

Greg

[eyecue]

[Please login or register to view this link] This is the transmitter output on the radio set to 28 MHz. As you can see it drops out jumps frequency etc. Nothing I adjust on the PLL board changes this. Also the meter is LCD and is just blank.

Update: That is my probe loading the PLL down. Interesting because it is a 1 M Ohm impedence. The LM7805 is running a little over and is showing about 5.5 Volts out. I cant get the alignment freq to lock so that I can adjust it, it jumps as much as 200 kHz and wont lock. I have two of these boards and they both do the same thing.

[Hawkei1967]

Are any of the cores in your oscillator IF cans flush with the top of the cans or bottomed out?

Have you checked the 10.240MHz crystal or the 10.695MHz crystal?

Did you reset the VCO back to specs?

Check all the chassis ground tabs to make sure they're soldered to board good, seen this mess up a lot of alignment attempts.

[eyecue]

This turned out to be someone put the unit back together wrong, there are two cables that have the same connector type on the control board. They were switched.

[MDYoungblood]

Glad to got them working.

3's

Greg