Spectra HHCH VCO unlocked

[kj6ko]

I have a A3 HHCH low split (403-433) UHF spectra that I can't get the VCO to lock. The SL+ V is steady at about 9.4V and the SL-V is steady at about -3.1V. I have tried programming anything from 403-440 into it and get the same FAIL-001 VCO error and same voltages on pins 3 & 4. .

First, let me say my goal is to ues this radio WITHOUT a control head as a link radio. Is there something about the HHCH radio that will not let me do this???

Not quite sure where to look. Here's some more info..

No caps were leaking, but I replaced them all anyway. Was it working before???..not sure. I didn't have an A3 head, so I jumpered pins 30 & 31 on the command board conn and it fired right up, read OK and programmed OK, BUT...I could not get the unit to TX or RX, even in the SERVICE mode to try to set power and WARP. I then bitbanged it to accept an A5 head and it works fine, vol etc, but has the VCO issue (FAIL -001). I'm hoping this is all moot and the radio just has a VCO issue, but I only have a serv manual for the ASTRO and don't know where to begin to look! Oh yes...It also has a securenet board internally that I disabled in RSS...if that was correct??? Can I now remove the securenet board or are there jumpers?? Anyway that's a different issue! more interested in the VCO.

Any help or point me to an online manual?(NLA) The radio has all the correct boards for the freq range etc. Audio works (beep).

ALSO...Tried a second identical radio...does the exact same thing! Back to the HHCH with no CH issue??? maybe it won't work without one with pins 30&31 jumpered???

I'm only good with 900 Spectras! This is all Greek to me!



Too much info!!??

Thanks...Greg

[Will]

Greg,

I replied via email..

BTW, Greg found the VCO was NOT the problem. The culprit was capacitor leakage damage on the RF board.

[kj6ko]

More on this....
So I swapped RF boards with another 420 non-HHCH A5 radio and the HHCH radio worked fine. Aparently both HHCH radios original RF boards are bad?? Now, I am wondering if I can swap an RF board from any UHF spectra or does it have to be another 420 radio? Reason I asked is I pulled one from a 457-470 radio that was once working and it did not work either in the HHCH radio, but can't confirm that board was good! Have one more UHF board to try. Any ideas??

Thanks...