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Gotta Re-Flow dat VOOODOOOO!!!
More boring 'BS'...
Well, this is a problem that is very common on all TS-950SDX rigs.
The TRX sub board (X59-3680-00) which is located on the Control Unit (X53-3380-00)
gets very hot during operation. So hot in fact, it will actually melt the solder on its components.
The TRX Board generates the Transmit and Receive DC voltages for the Rig.
It develops the Receive DC voltage called RXB and the Transmit DC voltage which is called TXB.
When the Rig is in Receive mode, the RXB voltage is switched to all the receiver circuits.
Once the Rig is keyed for TX, the TRX board turns OFF the RXB voltage to all the receiver circuits,
and then turns ON the TXB voltage to all the Transmit Circuits.
Once the rig is un-keyed, The TXB is turned OFF, and the RXB turned back ON.
From a combination of poor solder flow at the Kenwood factory, and the heat generated on this board,
the solder tends to melt ultimately causing an intermittent connection.
This normally happens on the two resistors R155 and R156, but we have seen this on all the components.
The symptoms of this problem are the rig will operate normally at first start up when its cold,
then it will not key up when the rig gets warm. The Receive may also drop out in extreme cases.
This will progressively get worse as time goes on.
The fix is simple, just reflow all the solder connections on the components with solder.
We use a high melting point silver solder, but regular solder will do just fine.
The TRX Board can be accessed by GENTLY bending it back, and GENTLY bending the board above it away.
Of course the Control Unit will have to be removed to accomplish this.
Be careful with R155 and R156, they are usually very loose and just touching them with
the soldering iron is enough to knock them off of the board!
Reference the pictures below to locate and repair the TRX Board...
You fixed it!
These mods are getting easier and easier!
Ya'll Take Care!!