Kenwood TS-790A DEAD!

[Mogman]

I have been asked to look at a Kenwood TS-790A by a friend that is pretty much dead, the only indications of life are, the meter lamps light, the "channel busy" lights come on if the squelch is turned all the way down and the audio section seems OK as I can hear static when moving the volume controls, otherwise it is dead to the world no display, nothing, I do not speak Kenwood being an Icom and Motorola guy, I am pretty disappointed in the lack of information and the very poor circuit board layouts in the service manual but nothing can be done about that. I have been looking for a power distribution failure as it seems that would be a good possibility but have not found any voltages missing yet, everywhere I look -22v 13v 5v and 8v are all fine.
73
Craig

 

[jim202]

I have been asked to look at a Kenwood TS-790A by a friend that is pretty much dead, the only indications of life are, the meter lamps light, the "channel busy" lights come on if the squelch is turned all the way down and the audio section seems OK as I can hear static when moving the volume controls, otherwise it is dead to the world no display, nothing, I do not speak Kenwood being an Icom and Motorola guy, I am pretty disappointed in the lack of information and the very poor circuit board layouts in the service manual but nothing can be done about that. I have been looking for a power distribution failure as it seems that would be a good possibility but have not found any voltages missing yet, everywhere I look -22v 13v 5v and 8v are all fine.
73
Craig

Have you asked the friend if the radio ever worked when he had it?

What frequency is programmed into the receiver? Have you tried injecting a signal into the receiver with a signal generator on that frequency?

Is this a used radio that was just purchased?

Was anything recently done to the radio, like try to program in new frequencies?

Does the transmitter work and put out power as measured with a watt meter?

You really need to read the radio with the programming software to see just how the radio was set up. The receiver may be set for tone squelch and not programmed for off hook monitoring. If that is the case, you might not hear anything.

Need some more feedback before anyone is going to be able to help you much.

 

[Mogman]

The owner said it worked fine when he turned it off one night, next day nothing, other than what I said,, it does nothing, no receive noise, no modes, no display, no lights other than described already, no tx, no response to any control other than the squelch as described before, sorry I cannot give any more symptoms but it has none!! checked power going and coming from most of the boards and have not seen anything missing, of course the manual gives almost no information on voltages, signals etc. Only someone that has seen this before (and was able to fix it) could help.

 

[Mogman]

This is a dual band HAM radio not a commercial radio that needs programming software, it is a full size multi mode base Sta. with a vacuum florescent display...

 

[mrweather]

You really need to read the radio with the programming software to see just how the radio was set up. The receiver may be set for tone squelch and not programmed for off hook monitoring. If that is the case, you might not hear anything.

TS-790 not TK-790.

 

[scrotumola]

Have you tried to reset the microprocessor? (Hold down A=B on power up)

~S~