Alinco dr-599 off freq on rx

[kc4umo]

Been beating my head on this one, Alinco duel band mobile.
Uhf side works great. But Vhf side has problem The receive is off by 1.5 kc. The schmatic is very poor and so is the service manual. Has 2 crystals on the main board. A 12.800 close up by the vco circuit. When tuning it seems to move tx freq the most.

The other crystal is a 22.05 mhz. No tuning cap. I may be wrong but think this is the rx mix crystal. If so may be screwed. For alinco tells me this is no longer available and they will not give out the crystal fundamentals to have one made.

I removed the crystal and designed a 1/2 inch by 1/2 inch circuit board. Mounted the crystal along with a varible cap. Installed and was able to move rx freq .5 kc. Further away.

So if anyone knows where a dead dr-599 is laying around let me know.

Thanks

[n3zjp]

Kc4umo,

Good day, I wonder if you solved this issue with your Alinco? I have the same unit with the same issue. Another ham noted that he found a blocking diode in the VHF PA was bad. No comment on whether it was shorted or open. Replaced it and all is better. Current, I guess, is feeding back into the receiver and this is creating the off-freq. seen at the tail end.
the VCO is right on, on mine as well. I have not looked at the mixer crystal, yet.
Sorry, I do not know which diode was replaced, either.


N3zjp / Todd