?
Stan,
?
I'll have to break out my actual service manual
rather than rely on the pdf version. I'm sure there is a legend somewhere but
it's?very time consuming?to find in the pdf.
?
I'm tempted to say those voltages are in Rx and
then Tx but I'm not 100% certain of that...Maybe someone else knows, but in the
meantime I'll pull my SM copy and check when I get a chance...
?
73...Jordan VE6ZT
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----- Original Message -----
Sent: Sunday, February 25, 2024 9:37
PM
Subject: Re: [Kenwood-Amateur-Radio]
TS-690S transmits on 6m but not on HF
Jordan,
?
I’m just now getting used to the layout of the service
manual, so your pointers have saved me a lot of time and
frustration.
?
Any idea what the voltages in parentheses represent? I’m
sure there’s some sort of explanation somewhere in the manual, but I haven’t
found that yet, either!
?
I’ll report back what my measurements show.
?
73,
Stan N6BYU
?
?
According to Item 2
of the TX Adjustment on pg. 124, you should measure ~10dBm minimum at
CN-9 on the RF board.
You should be able to connect your SA through a DC block?across the
output of the cable connected to CN-9, or connected across the?other end
of the CN-9 cable?itself.
Personally, I use a
section of .141 rigid cable with?an SMA female connector on one end, then
I can connect my RF millivoltmeter or when necessary, my
SA.
Page 163 shows RX and
TX stage AF and RF levels as well...
----- Original
Message -----
Sent: Sunday, February
25, 2024 3:24 PM
Subject: Re:
[Kenwood-Amateur-Radio] TS-690S transmits on 6m but not on
HF
Using my spectrum analyzer, I placed an RF sniffer probe
near the output connector of the of the HF amp board. I saw activity at the
proper frequency, but at a very reduced level as compared to what I saw when
transmitting on the 6 meter band with the probe near the 50 MHz output
coax.
I've looked at the HF amplifier schematic in the service
manual, and it shows what I assume are DC voltages at various points around
the board. Some points show only a single voltage, and other points show a
second voltage in parentheses. I assume that the first voltage is measured
in the receive mode, and the second voltage (if present) is measured in the
transmit mode.
I don't see any references to what HF levels I should
see at the various points in the signal chain.
I'm thinking that the
low output is due to either a failed transistor (or transistors), a problem
with the level of the RF input to the board, or a poor connection at one of
the connectors, but without knowing what the expected RF levels at the test
points are, I would just be guessing.
Any help on how to proceed from
here is appreciated!
73,
Stan N6BYU
