Batboard

Ok here we go again. I got into my truck for a call and I could hear my dispatcher as i always do. I went to call in service and no go. I got an error tone and FAIL 001 on the screen. The radio is a Spectra A9 high power 145-174 or something close to that. I have had the VCO go on my UHF A7 mid power unit and I had no TX or RX. So why am I getting a Fail 001 and still have clear RX? Maybe a leaking cap? and if so would I check the VCO or the PA? any help would be great.

Cap is likely, might also have damage from the leakage. Info on this is in the archives or you might want to contact batboard member Will, he does the repairs to remidiate the damage and replace the caps.

I rarely see the VCO fail as you describe. Usually the RF board synth has a problem due to damage from the leaked electrolyte.
When you transmit, the VCO has to shift a ways and the synth circuit can not lock at the transmit frequency, 1/2 the VCO frequency.

Will I replaced to caps C636, C635 and one transQ607 on the RF board. The radio worked fine at first then I got a fail 001 again so I got a little hot headed and keep keying up the radio. After pressing the PTT three times it keyed up fine. Now the radio still shows fail 001 when I key up but if I hold the PTT for two or three secs the radio keys up ok. Is this from a low swing voltage?

No, that is from the comtamination on the circuit board from the leaked electrolyte. Did you thourghly clean your RF board's aera arround the bad caps?

Yes I cleaned the board very well. The problem seems to have just gone away. The radio is working fine now. But the fact that the radio just started to work as it should out of the blue does not sit well with me.

Well, this is the mystery of the leaking caps. I have done ongoing research/engineering to try to determine just what happens.

Most of the time the leaking electrolyte eats away at the traces on the circuit, gets under adjacent parts and we have even seen
damage to the Synth IC. One thing I have found is the round SM cap design is poor, so I use a completely different type of cap. You
could use the radial leaded caps without problems. They are much easier to solder in.

I would recommend removing the RF board and cleaning it again.

Will,
What is the best cleaner to use? Is it OK to use an untrasonic cleaner bath?