Schematic Needed Technisonics Model TFM-403 (Or TFM-30 or TFM-138) UHF
FM Air to Ground Radio.

I am trying to troubleshoot an early serial number radio (25 KHz BW)
that has a display multiplex problem. Only the upper left quadrant works
and only briefly for about 30 seconds. The other 3/4 of the LEDS have
all segments illuminated. When first turned on the upper left quadrant
works and I can see and use most of the main radio functions. Then after
30 seconds, the upper left quadrant either fades away or some segments
light up like the rest of the display. I am suspecting physical damage
since the front lens is cracked and a keyboard button (#2) is popped
off. Otherwise the radio seems to TX and RX OK!.

I need help finding a schematic of the control board and display. I have
a TFM-403 UHF radio but I think the other two models mentioned above
probably are similar.

I would also appreciate hearing from techs with familiarity of this
model. Also need some cosmetic parts if you can help. I want to fix
myself. not to send to a depot. Its for my ham shack! Thanks!

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

**THE-RFI-EMI-GUY** wrote:
Schematic Needed Technisonics Model TFM-403 (Or TFM-30 or TFM-138) UHF
FM Air to Ground Radio.
I am trying to troubleshoot an early serial number radio (25 KHz BW)
that has a display multiplex problem. Only the upper left quadrant works
and only briefly for about 30 seconds. The other 3/4 of the LEDS have
all segments illuminated. When first turned on the upper left quadrant
works and I can see and use most of the main radio functions. Then after
30 seconds, the upper left quadrant either fades away or some segments
light up like the rest of the display. I am suspecting physical damage
since the front lens is cracked and a keyboard button (#2) is popped
off. Otherwise the radio seems to TX and RX OK!.

I need help finding a schematic of the control board and display. I have
a TFM-403 UHF radio but I think the other two models mentioned above
probably are similar.

I would also appreciate hearing from techs with familiarity of this
model. Also need some cosmetic parts if you can help. I want to fix
myself. not to send to a depot. Its for my ham shack! Thanks!


According to the Technisonics website, they will share with you the
repair manual and all technical bulletins for "only" $50:

http://til.ca/index.php?option=com_c...28&Itemi d=62