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[W4AJF]

Hi all, I need help with 2 issues for a Kenwood TS-450SAT:

Issue #1: So I have 2 of the IF boards and I see no leakage on the infamous C104 and I realize it still could be an issue so my problem is is that one of the other boards receive fine but will not let the radio go in to transmit. When I key up (mic, send, CW key) the radio just stays in receive. With the other IF board it transmits fine. 
Hopefully someone has seen this and knows what it is.

Issue #2: The tuner "works" but on some bands with the tuner engaged I get only like 25-30 watts out and others I get near 100 watts out (that's what the radio does without the tuner engaged) so how I do I get the  bands with lower output when tuner engaged to come up in power?

Thanks for any help!

Adam Farber W4AJF
Cooper City, FL

[KE0STT]

I don't know about issue number 1 in your post. Can you provide a little more information about issue number 2? What bands are low output and what antenna and feedline are you using?

[W4AJF]

Hi, I figured out the tuner issue, thanks, I still need help with the one IF board that won't let the radio go in to transmit mode. Thanks, Adam W4AJF

[KE0STT]

You are most welcome. Sorry I couldn't be more help on the IF board issue.

[WB6BYU]

Issue #1:
...is that one of the other boards receive fine but will not let the radio go in to transmit. When I key up (mic, send, CW key) the radio just stays in receive.

I'm assuming that reseating the boards hasn't helped,
since you have tried both in the radio (sometimes that
clears a bit of corrosion on a connector).  And that all
of the jumper cables got plugged in correctly.

In that case, the best way to trouble-shoot it is to
measure voltages along the T/R line on both boards
and look for a difference between them - that should
narrow down the problem pretty quickly.  (This might
be easiest if you can put each board in a radio and
have them functional at the same time, but could
be done by taking a set of measurements, swapping
boards, and taking another.)

In general, this is a good procedure when you have
one good board (or radio) and one bad one.

Issue #2: The tuner "works" but on some bands with the tuner engaged I get only like 25-30 watts out...

I know you said you fixed this problem, but one thing
I discovered with my radio is that the tuner isn't always
very efficient.  It has two motor-driven capacitors and
a band-switched coil in a T network, and actually can
match a fairly wide range of impedances, at least on
some bands.

But after doing some testing, I discovered that, with
some loads that the tuner would match, a good manual
tuner gave me 3 dB more output to the antenna.  That
means that over half the power is being dissipated in the
tuner, which probably means it is going to overheat with
any sort of extended use.

So, while it may have a fairly wide matching range, that
doesn't mean that it will always be efficient, even when
it can get a good match.

[W4AJF]

Hi, thanks for the post, I am not quite good enough to figure out how to trace the voltages on the T/R line but thanks. I am still hoping someone has had the same issue and knows what to do.

Thanks again, Adam W4AJF