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Ok, I have done some additional test at 10M where the supply current is
around 15 amps. When in FM TX, there is a quick rise in temperature on
the
surface of the board near the circuit of L303 located between the two
power
FETS. Power setting has no affect on the results.
Could there be an oscillation???

I have attached this portion of the schematic.

Any suggestions are appreciated

Thanks
Tommy KF4RWG


On Wed, Jan 22, 2025 at 1:30?PM Tommy Wooten via groups.io <kf4rwg=
[email protected]> wrote:

I received the radio in this condition. The only evidence of rework

from

the previous owner was the rx/tx relay had been replaced. Some of

the thru

holes for the relay leads had been disturbed. Maybe the “no TX”

issue was

the reason the owner replaced the relay. I removed the relay and

closely

inspected the traces and thru holes. Everything seems to be intack.

As I

mentioned, the receive works exceptional in all bands. This tells me

that

all LPFs are working. I tried the TX TOTAL GAIN adjustment procedure

but

no increase in power out.

I am adding a couple of schematic views. First is the rx/tx relay

just

beyond the PA circuit. The second is the forward/reverse detector

for the

power control and SWR.

Thanks
Tommy KF4RWG


On Wed, Jan 22, 2025 at 8:50?AM Andrew Lenton via groups.io <a=
[email protected]> wrote:

True, but nothing is coming the aerial socket so there is an issue

post

PA and LPF probably a pin diode!

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On 22 Jan 2025, 13:35, at 13:35, "J.D. Barron via groups.io"
<jeter.d.barron@...> wrote:

If there is a problem with the transmit chain before the forward /
reverse power measurement circuit reducing the power may not change

to

amount of power drawn by the PA.
Most transceivers control the drive from the forward power measured

by

the For/Rev circuits.