Texas Star 500 4 pill 2879's

[unit100]

Pills appear to be OK after lifting top (cut off connector) and bottom and checking. Unit keys up but no output. One resistor from input to ground was burned. All pills ohmed to almost a full meter and were uniform.

Voltage is about five volts under radio key up on pill where the resistor burned. About 10 volts on other pills. This measurement was taken at input of pill or opposite of the cut off connector of the pills.

All I get is radio output. No other obvious burned parts. Looks like a signal type transistor has been replaced at one time near the relay, as it was clipped and the new part soldered on top.

Thanks for any help in advance.
Buddy S.

 

[mackmobile43]

Are you saying that one of the 10 ohm resistors from the input side of a transistor was burned? if so that would indicate a problem in that stage and usually indicates a blow transistor.

Check transistors in that stage like this, put the negative lead on the tab with the angle cut or the collector and touch the positve lead to all others in the diode mode and they should read in the 550 to 575 range if they totally gon short or read musch higher such as in the 700 to 900 range the transitor is leaky.

You should have continuity across the emitters or ground and read nothing from the base to any others with the positive lead attached to it.