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Andrew,
I have done some more measurements as you recommended. I removed the
PA
board and attached a connector to the output of L305 separated from the
rx/tx relay and HPF. I have attached photos of the input and output
voltages set at 10M USB with voice into the microphone. These voltages
are
much less than what you said they should be. The problem must be up
stream
from the PA FETs.
The oscilloscope was set at 50 millivolt per div in both photos. The
voltage was lower at the output of L305.!? But measured about 6 watts
on
the external power meter into a dummy load.

The vhf/uhf works well so the driver is working.

Thanks for your help.
Tommy



On Sun, Jan 26, 2025 at 10:55?AM Andrew Lenton via groups.io <a=
[email protected]> wrote:

This is a very hard radio to work on, as you cannot easily get to the

PA

board the way it is mounted and soldered into the pa driver board



I would remove the PA board, replace L305, for starters while it is

out

you can inspect the components one by one.



This unit does not lend itself to test and measurements, as all you

can do

is prod the rear.



All 12V HF PA stages have an impedance in the milli Ohms 0.4 to 0.6

ohms,

as it draws 20A, or so, the output transformer has to match 0.6 Ohms

to a

50 Ohm, so it needs to step up the voltage.



The problem is it would be nice to lift L306 and put your Watt meter

in

there, but you have to rip the PA board out then put it back together

to

make the measurement, so impractical



To protect the PA the is a coupler to control power and to protect

the PA

against hi SWR, however, if no power is getting past the coupler you

will

have full power 24/7



There could be a fault here:





But only you can trace, so measure i/p to L305, you will get a

voltage,

the out put will be higher at 100 Watts 50 Ohm the voltage will be

70.7V

RMS, so PTP on a scope 200V if you are not getting this on the O/P

then

move back to the I/P you should get 13.8 V to 40V PTP. I have one of

these

in bits working before I box it back together I will make some

measurements

and send back to you. as the PA in not loaded with 50 OHM, the

voltage can

rise too high

You need to set a voltage on Ref or FOR to knock the power back to a

few

Watts then you can uses CW and safely trace you signal.





KR



Andrew G8UUG







-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Andrew Lenton
Sent: 26 January 2025 10:00
To: [email protected]
Subject: Re: [ic7000] IC7000 no HF Transmit



This is a very hard radio to work on, as you can not easily get to

the PA

board the way it is soldered into the pa driver.



I would remove the PA board, replace L305, for starters while it is

out

you can inspect the components one by one.



This unit does not lend itself to test and measurements, as all you

can do

is prod the rear.



All HF PA stages have an impedance in the mOhms .1 .2 ohms as

thet6drsw

20A, the out put transformer has to match .1 of an ohm to 50, so it

needs

to step up the voltage.



KR



Andrew



I have a wiring unit, I can make some measurements for you



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On 26 Jan 2025, 01:32, at 01:32, "Tommy Wooten via groups.io" <
kf4rwg@...> wrote:

Bob, Thanks for the encouragement

I have considered all of the suggestions for troubleshooting the

problem I have with the IC7000. I have tried to trace the HF RF

path

with an oscilloscope from where the signal comes through the cable

from

the main board to the PA board. I have traced the signal and

inspect

all components through to the output at ant1. The signal seems to

loose its punch where the PA FETs combine into the L305 transformer.

The bias setting of the PA FETs seem to be correct. After the

signal

reaches the rx/rx relay it passes through the selected HPF where it

reaches ant1. The resulting signal is only a few milliwatts. I

have

tried to keep the setting in SSB and I see modulation when speaking

into the microphone.

I know it is difficult to troubleshoot the issue remotely but I

appreciate any and all ideas.

Thanks

Tommy. KF4RWG

On Sat, Jan 25, 2025 at 6:31?PM Bob via groups.io <W4JFABob=

[email protected]> wrote:

Well this is #30 then. That's OK because when the rest of us have

this

problem we'll appreciate every one of these replies.

Keep on writin' you guys.

Bob W4JFA

On Thu, Jan 23, 2025 at 4:40?PM Geoff via groups.io <vk3zgw=

[email protected]> wrote:

Forgive me if this has been mentioned before but as this is the

29th

reply I haven't gone back and read everything.

I always go first to where the effect of a fault is obvious

without

any

ambiguity, in this case the rf output ie Ant 1 connector, working

back to

eliminate ALL the stages involved, including in this case the

SO32

jack.

Good luck.

Geoff

VK3ZGW