Loss of single band transmit - Elmers Forum at eHam.net

$\'\'$

$\'\'$

$\'\'$

eHam.net Forum : Elmers : Loss of single band transmit

Forum Help

1-9 of 9 messages

Page 1 of 1

Loss of single band transmit	Reply
by N3ZKP on December 28, 2003	Mail this to a friend!
I discovered this morning that my TS-570 has no output on 20m, but instead the internal SWR meter pins at max. My external meter shows no output. This condition exists from 10.500 mhz to 14.499 mhz. This exactly coincides with relay clicks indicating, I assume, a change in output filters. 10.499 and down are fine, so is 14.500 and up. Do I have a blown filter? There was no indication of any problem last night when I was on 20m. Thanks for any input, Lon

RE: Loss of single band transmit	Reply
by K4SFC on December 28, 2003	Mail this to a friend!
Check all circuit board screws for tightness and starwashers. Check all internal cables (plug-ins).

RE: Loss of single band transmit	Reply
by N8YV on December 28, 2003	Mail this to a friend!
Band-pass relays are a possible fault, but I would first recommend that you check the rig for any faulty interconnect cables. I had a very similar problem with my ICOM rig (affecting only the 6-meter band) and discovered the fault was a defective inter-module connecting cable that was pinched between the cabinet and a heat sink.

RE: Loss of single band transmit	Reply
by AC5UP on December 28, 2003	Mail this to a friend!
I had an Icom do exactly the same thing, but mine had the courtesy to puke & die while under warranty. Bad relay and/or driver transistor in the TX output filter and I was told Icom swapped the board. Hasn't missed a Q since. The hardest part of the repair will likely be in getting the parts if you decide to roll your own.

RE: Loss of single band transmit	Reply
by W3JJH on December 28, 2003	Mail this to a friend!
Lon, If you're lucky, it's the driver transistor for the 20-m relay. If you're somewhat less lucky, it's the relay. If you're really unlucky, it's the digital circuit driving the transistor. I'm not sure if the relay driver transistors on the 570 are driven via a buffer (easy to buy, a pain to replace) or via a port on an custom PGA. If that's the case, it's time so send the radio over to Jim Kasunic, KA3LPC, in Walkersville. He repairs Kenwood radios. 73 and a belated Merry Christmas, John

RE: Loss of single band transmit	Reply
by N3ZKP on December 28, 2003	Mail this to a friend!
John, et al: Thanks for the various answers. This happened with NO indication of problems and the rig hasn't been moved around. Of course, I'll open the case and check cables first. John, Thanks for the heads up on the shop in Walkersville. I was not aware of him. The last Kenwood shop I was aware of was Amateur Radio Center in Hampden and it's been defunct for about three years now. :( Lon

RE: Loss of single band transmit	Reply
by N2MG on December 29, 2003	Mail this to a friend!
Not sure about your model specifically, but many Kenwoods (the TS940 was notorious) have what some call "connectoritis". The multi-wire female connectors develop poor contact with the male pins on the various PC boards. Simply unplugging and replugging them "wipes" the contact and you are back in business. There are dozens of them, but checking your schematic should reveal the one that may be the culprit in your case. Mike N2MG

RE: Loss of single band transmit	Reply
by N3ZKP on December 29, 2003	Mail this to a friend!
Thanks, Mike. Lon

RE: Loss of single band transmit	Reply
by KD7EZE on January 3, 2004	Mail this to a friend!
Not a repair solution, or a gripe. Just another proof of my original theory, "multiband rigs are an accident waiting to happen". I prefer a seperate radio for each band of operation, and also, a seperate antenna for each radio. Sure, my QTH looks like I'm in constant contact with the "Mother Ship", and my truck looks like a porcupine, but it works for me :) KD7EZE

Page 1 of 1

Next Topic: FT-100D SOFTWARE
Previous Topic: IC706mkIIG attenuator

Email Subscription
You are not subscribed to this topic.

Check our help page for help using Forum, or send questions, comments, or suggestions to the Forum Manager.

$\'\'$