The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

I am working on a texas ranger tr-127fs radio the face lights up and the channel display lights up as soon as i key the radio the led display goes out. it does this on cb and pa i checked b+ at the pll and it drops to zero when you key the radio rx also does not work. no audio on pa either. tried to use the ranger service manual but it did not list any voltages to check so i am hoping someone else has had this problem.

thanks,

Mike

It sounds like it as been wired up the wrong way round, check D23 near the power socket it maybe o/c, has for no RX try replacing the audio chip IC1, as for on TX check the transistors TR24, 25 and 28.

I have power on the pll and at the power switch. i loose power at the pll chip when i key the radio. i removed the audio chip and it still drops power as soon as i key the radio even with tr 24 removed. would a bad pll chip like ic2 cause this problem????

Mike

Try un-soldering the Pin9 of the PLL to see if the fault go away, It not common to have a PLL go short.