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142 gtl blowing fuse at turn on
- Thread starter kaos513
- Start date
Negative, the fuse is on the secondary side of the transformer, either the bridge rectifier has failed short or the filter capacitor (C304) has failed short. Check those two components and let us know how you get on. 
~Cheers~
~Cheers~
The transformer is probably the most reliable single part in the radio. Until lightning hits a utility pole down the street while it's plugged in to the wall outlet.
Flip the "AC-DC" switch on the rear to "DC".
Now see if it still pops that fuse.
If so, I have to wonder if C504 got turned around backwards when the radio got recapped.
And if the fuse holds with the switch set to "DC", this means the overload that popped the fuse is downstream from that switch, somewhere on the radio circuit board.
73
Flip the "AC-DC" switch on the rear to "DC".
Now see if it still pops that fuse.
If so, I have to wonder if C504 got turned around backwards when the radio got recapped.
And if the fuse holds with the switch set to "DC", this means the overload that popped the fuse is downstream from that switch, somewhere on the radio circuit board.
73
Some of the last 142GTL's built didn't use the best bridge rectifiers or heatsink. It was cheaper to mount the rectifier right to the PC board and just use a small heatsink rather than wire it off board to the main power supply heatsink. If the filter cap is in right, check the bridge rectifier next. This assumes the fuse still pops with the AC/DC switch in DC so it removes the radio from the power supply.
I'm not sure but the ps is on 24/7 I think.
Check your voltage with CB off.
You got a shorted final maybe
Check your voltage with CB off.
You got a shorted final maybe
One side of the red wire to transformer reads 18.00vac other red wire to transformer reads 6.00vac
desoldered the 2 red wires coming out of the transformer one red wire reads 0.745vac other red wire reads 19.05vac
Uh oh.
The red wires are supposed be both isolated totally from ground inside the transformer. If the measurement you made was from each red wire to chassis ground, they should read the same.
Time to put one lead of the ohm meter to chassis ground and the other one to either red wire. Should show megohms or more.
73
The red wires are supposed be both isolated totally from ground inside the transformer. If the measurement you made was from each red wire to chassis ground, they should read the same.
Time to put one lead of the ohm meter to chassis ground and the other one to either red wire. Should show megohms or more.
73
Shorted secondary winding. Should not show any continuity to ground with both red wires pulled from the circuit board.
Dern!
73
Dern!
73
Transformer is on my bench I used continuity on my meter it beeps so means the trans former is.good ?
It's pulled and now I have one lead to chasis ground and one lead to red wire I do not get anything
Update: I changed c304 and c302 fuse doesn't blow hear hum on transformer but still radio doesn't power up