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Re: IC7000 no HF Transmit


 

Very well said, Tommy has removed the PA transformer and resolder it top side, but he was still only getting low power, so does not make much sense

KR


Andrew

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On 28 Jan 2025, 22:45, at 22:45, "J.D. Barron via groups.io" <jeter.d.barron@...> wrote:
(PA 1) The RF comes from L305? through HF03 to RL-801 (PA 2) (changes
from orange to blue and out through (A). to
(PA 3) the bandpass filters. There are a pair of relays that have to be
energized for each frequency band. The input relays are controlled by
L1 - L7 (Bus line 3) from the (PA 3) Q980 - Q987 by the outputs from
IC981. (Powered by 3R3V)

14 VR provides the operating voltage for these relays and the output
relays. (At this point I have to say I have not looked long enough and
hard enough to understand how the output relays are activated but they
must be.) as each band is selected by L1 - L7 going low.
VR14 comes from RL701 output through L981 and resistors R1002 (150 ohm)
and 1003 (180 ohm) (paralleled). This line also provides power to RL801
which would also stop the RF power from getting to the bandpass filters
HF03 (Orange) to A (Blue). If R1002 and R1003 were open this would
cause this problem as well. One of the anti-flyback diodes shorted
could take out these resistors

I think that as each L1 - L7 goes low that low is transferred via the
blue line to the normally closed contact on the relay below to ground
on the unenergized relay (I think).

I would verify that the VR14 voltage is present first and then - if
present

I would look for the L1 - L7 signals being pulled low by Q980 - Q987.
end then If switching I would look to
The outputs on IC981.

I believe you will find the problem in this area as you are drawing
current indicating power being produced (unless the current is not in
the 1-3 Amp range in SSB no modulation idling current).

Since the power is not going through L961 the FOR / REV (SWR)
transformer and being read by IC060 (JFOR) the RF drive is going to the
point of current limit and cannot be adjusted in any carrier mode with
the power adjustment.

Just my best guess without making some measurements, but this is where
I would start.

Good luck and best regards.

JD
KE4MD


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