Kenwood TS-590 that's had 1kW of LF RF up its RX antenna port!

[Chris Wilson]

Due to a failure in a TX / RX relay after a 1kW amp on 136kHz my venerable Kenwood TS-590S transceiver got a kilowatt of 136khz up its receive antenna port. The result of course is not good. I was disappointed to find Kenwood cannot supply a new RF board, and they class this 5 year old rig as obsolete    I can get a US spec RF board from America for about £200 and I *THINK* it only differs in not having two trimmer caps and two inductors that make up the broadcast band filter on European spec boards. But before I take this costly and somewhat risky purchase I wanted to have a go at seeing if I can determine the extent of the damage. I fixed another issue ages ago, but this is far worse. I need to know at what frequency a modulated test signals should be injected, based on this service manual block diagram to see if the damage stops before the mixers or goes beyond them. I am not sure what frequency to inject should I find a dead mixer. In other words after a dead mixer, can anyone help please? Thanks!

[CJay]

Is it just 'deaf'?

Does it TX?

On the correct frequency?

The service manual tells you that for a 14MHz, -113dBm input signal at the antenna jack you should be seeing a signal at -107dBm after the first RX mixer 1 so I'd be injecting a -107dBm signal after that mixer at 11.374MHz which is the first IF filter centre frequency, if I were testing it.

After 1st RX Mixer 2, -102dBm @73.095MHz

If you need a hand and you're local ish to Manchester, let me know

[Paull Karll]

Shop for a "parts only" buy off of QRZ's swap meet forum. www.qrz.com
Easiest way to find a part that you will fit.

[Chris Wilson]

Looking at buying a new US spec RF board, as far as i can tell it only differs from the EU spec boards by not having 2 small chokes and two small ceramic trimmer caps to form a broadcast band filter on the EU spec machines. the pads and through holes are there so i could swap my components or just fit new. but that's assuming the schematics tell the full story..... Thanks Paull