Batboard

I have a high power Moto Spectra VHF drawer that has an odd problem.
It receives fine, will take a code plug and tune from 140 to 156 on receive for sure.
It doesn't generate ANY RF on transmit anywhere. Even with the top cover off and the shield off the RF amp and VCO a radio placed near it hears nothing from it.
As well, I an getting no measurable RF into the exciter or amp board when checked with a scope.

Any ideas would be a great help.
As of now I do NOT have a service manual for it so it's been a hunt and peck sort sort of thing with troubleshooting it.
I did bitbang it to the HAM split, but I also bitbanged it back to it's original split with no change.

Thanks in advance.

Well let's see, you do not hear anything. If the transmitter fails to lock the VCO and has no RF out the low frequency error tone should sound in the speaker, and the TX led goes out. Then you could check the the steering line voltage for a clue.

Actually, it receives fine. Just no transmit. I key it up and the TX light comes on and of course the receiver shuts up.
I tried it receiving from the lower part of the ham band up to the weather band (162.550) for receive and it's fine across the entire band.

I am at a loss in this one.

Then, from what you say, the VCO is locking to the TX frequency OK. The trouble may be on the VCO carrier board.

You could remove the 6 screws from the VCO cover, bottom side of the radio. Put two screws back in to hold the VCO in the radio. Then with a handheld radio receiving on the TX frequency see if you "hear" a signal near the VCO.

I checked that, got nothing.
Model number on the carrier board is HLD4342B/6062D

I am going to cross it and see if it's the right board.
I can see that someone has been working on it.
There are pads that have fresh solder but no components
there are components that have been removed and replaced that the looks like it was done without the aid of an SMD work station.

I am guessing that is it.
Now I need a service manual with a print for it.

That carrier board will have some omitted parts on it as it is used on several models. The VCO is mounted on the back of the carrier board.

Measure the DC voltage on the carrier board pins both in RX and then again in TX.
The first pin nearest the inside of the radio is the RF going back into the RF board's synth section. Here you can check with a frequency counter. On RX it will be + 109.65 mHz from the receive frequency.