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TS450S TUNING PROBLEMS

Posted: Fri Mar 07, 2008 2:53 am
by RIMSHOT
TS450S WILL ONLY TUNE 10 KCS AND THEN REVERTS BACK TO THE ORIGINAL FREQ.IF YOU INTER THE FREQ DIRECTLY FROM THE KEYPAD ,IT WILL WORK PROPERLY AS LONG AS YOU ARE TURNING THE KNOB CLOCKWISE. THE SECOND YOU TURN THE TUNING KNOB COUNTER CLOCKWISE IT REVERTS BACK TO THE PREVIOUS [BAND ] THAT YOU HAD BEEN ON. EVER HEARD OF THIS ,OR ANY IDEAS?

Kenwood TS450S Tuning Problem

Posted: Fri Mar 07, 2008 5:40 am
by WA9WVX
In the newer solid state transceivers, they incorporate an Optical VFO Chopper / Coupler that feeds the Up / Down I.C. circuitry to increase or decrease the uperating frequency and digtal display. Knowing Kenwood's track record on their older transceivers, they have a notorious problem with the printed circuit boards developing "Cold Solder Connections" that essemtially open the circuitry connecting between the components and the plated foils on the PC boards themselves.

If you're capable of reheating the printed circuit board connections, using the Kenwood Service Shop Manual with full schematics and PCB overlays. Then I would suggest using a very small Pencil Tip Temperature Controlled Soldering Iron Station with Kester 60 / 40 Solder, a large magnifying glass to view the board connections with a high intensity light and carefully touch up the component to printed circuit board connections on the Up / Down Counter Board.

**** It's very important while reheating the Solder connections not to allow the solder to flow across other PCB foil connections or plating therefore causing "Solder Shorts" that can damage other components and circuitry.****

If you don't feel comfortable attempting this repair process then find a good reputable service shop to troubleshoot the problem and do the required soldering on the printed circuit board. It's a time comsuming process locating the defective solder connections and do not expect a small charge for the work performmed.

73,

Dan
WA9WVX

Re: TS450S TUNING PROBLEMS

Posted: Sun Mar 09, 2008 5:20 am
by wa4cch
RIMSHOT wrote:TS450S WILL ONLY TUNE 10 KCS AND THEN REVERTS BACK TO THE ORIGINAL FREQ.IF YOU INTER THE FREQ DIRECTLY FROM THE KEYPAD ,IT WILL WORK PROPERLY AS LONG AS YOU ARE TURNING THE KNOB CLOCKWISE. THE SECOND YOU TURN THE TUNING KNOB COUNTER CLOCKWISE IT REVERTS BACK TO THE PREVIOUS [BAND ] THAT YOU HAD BEEN ON. EVER HEARD OF THIS ,OR ANY IDEAS?

:idea: before you start soldering and take the chance of realy screwing up clean the molex plugs adound the vco one at a time pull one off and squrit somecleaner in the plug and push it on and off a coule of time that worked for me the pulg also are a trouble spot if your memorys aren't working right you might try a new mem batt

73 chuck