[net.ham-radio] Kenwood TR-2500 rig problems

Michael.Chepponis@C.CS.CMU.EDU (Mike Chepponis) (10/20/85)

Indeed, I have been experiencing a frying/popping noise in the transmit audio
on my TR-2500, most likely very similar to Bob, K9EUI's noise on his 7930/7950.
I have ripped out way too much circuitry for such a "simple" problem, but it
still hasn't gone away.  The noise appears only intermittently, and never has
it been > 1 KHz deviation.  So I live with it.

Since we're discussing rigs, I'd like to put in a strong plug for Ten Tec. I
have owned both the Triton 4 and now the Corsair and I have never had ANY
problems with the rigs - NEVER!  OK, the Corsair doesn't have a general
coverage RX, or as many spiffy features as the Kenwood TS-940S, but as far as
I can tell, the Corsair is a superior CW rig compared with the '940, although
on SSB the 940 has an edge with all of its bells & whistles.  I chose Ten Tec
because of all the HF rigs I was looking at at the time, only Ten Tec gear
looked like it could be fixed by an average ham...Peek into one of those
other HF rigs & say something nice about serviceability!

-Mike, K3MC
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jhs@mitre-bedford.ARPA (10/21/85)

Could the noises be the same old "Kenwood Crunchies" that used to plague the
TR-2400?  As I recall, this was caused by the PC board to chassis ground
becoming intermittent.  Tightening up the PC board mounting screws and maybe
soldering one of them in place cured the problem.  Putting a lockwasher under
one of them would seem a less drastic way of ensuring good contact.

I hope it's that easy.

						73,
						John S., W3IKG

jhs@mitre-bedford.ARPA (10/22/85)

Other possibilities for excessive crunchy noise are bad transistors (high
1/f or "flicker" noise), electrolytics installed with wrong polarity, or just
bad electrolytics (usually the reversed ones come back to life if installed
properly), or DC running through the wiper arm of a pot.  The latter condition
can be caused by leaking electrolytics, by the way.  Also loose connectors,
dirty transistor sockets, or dirty switch contacts.

I know, soak the whole radio in a sulphuric acid bath for about 24 hours, and
I guarantee you the noise will be the least of your problems.

						73,
						John S., W3IKG