Tm733-a transmit problems

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KW4AR

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Aug 15, 2014
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Germantown, Tn
I have a TM733-A that when you try to transmit on UHF or VHF, the s-meter goes up quickly and then falls off. No signal is getting out. Radio was stored for several years in the original box with no extreme temp. changes. Any help would be appreciated. Also,any knowledge of a repair facility would be great,in case I can't figure out problem. Great radioand hate to part with it if I don't have too. Thanks, John KW4AR
 

k3cfc

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Feb 27, 2011
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Beavertown Pa.
I have a TM733-A that when you try to transmit on UHF or VHF, the s-meter goes up quickly and then falls off. No signal is getting out. Radio was stored for several years in the original box with no extreme temp. changes. Any help would be appreciated. Also,any knowledge of a repair facility would be great,in case I can't figure out problem. Great radioand hate to part with it if I don't have too. Thanks, John KW4AR
Time is a capacitor's worst enemy. i would recap it and go from there. download a service manual for help.
 

AK9R

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The TM-733 is not that old of a radio. They were in production in the late 1990's. While old capacitors could be the problem, that's not the first place I'd look on a modern solid-state mobile radio.

Check your power supply. The radio draws 10-15 amps at 13.8 volts when transmitting on high power. If the voltage from the power supply sags too low when a load is presented, the radio will respond by shutting down the transmitter or cycling the CPU (which would make the display reset).

Also check all of the connections between the power supply and the radio. If the inline fuses are still in place, the fuse holders may have picked up some corrosion which would cause a voltage drop at the radio. Same goes for the T-shaped power connector...make sure it's not corroded.

Best options for Kenwood service are the authorized Kenwood service centers listed on the Kenwood web site. The first two listings here handle amateur radio repairs. Take note of the Out of Warranty Repair info at the top of the page. Cliff at Avvid also does good work and may be able to help if Kenwood can't.
 

SCPD

QRT
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Pa

Sometimes the PA IC goes bad in this you could try to resolder it but I would get a new one from Digikey,or your favorite electronics store.Usually this IC takes a dump.This is just an illustration of what it sort of looks like not the exact,replace the part with the exact part inside YOUR radio.P.S.dont touch the clear goop!
S-AV17 they have a crossreference for some new version by now I'm Sure!
Sometimes you can get lucky and if you pop the black cover off the IC you can resolder the traces and that will bring it back.
Repairing the Toshiba S-AV17 RF power module <<<<<<shown here
$35 on ebay just get a new one.

Theres 3 videos on youtube heres one


Kenwood TM-733 Repair Part 1 - YouTube

Kenwood TM-733 Repair Part 2 - YouTube


http://www.youtube.com/watch?v=kJUfaywS9tI <<<another look from another dude



If you are NOT technical call this guy he does wonders >>> http://www.hamrepair.com/


DONT FORGET TO UPDATE US ALL OF HOW YOU DID.
 

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KW4AR

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Aug 15, 2014
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Germantown, Tn
Thanks for the replies. It turned out that my power supply wasn't doing its job, and the transceiver was not getting the right voltage/ amperage, got a new pwr supply and all is good, 73's kw4ar
 

SCPD

QRT
Joined
Feb 24, 2001
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Location
Virginia
Kenwood

Thanks for the replies. It turned out that my power supply wasn't doing its job, and the transceiver was not getting the right voltage/ amperage, got a new pwr supply and all is good, 73's kw4ar
Ah just like a Kenwood,keeps going and going!
Good show !
 
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