Presiden Lincoln II Plus - TIP36C getting hot

[Ragon50ohm]

Hello everyone,

I have a President Lincoln II Plus (PCB 20160614).
I bought the radio with a defective display. There were damaged tracks, I repaired them and the device works again.

The receiver works and the transmitter also delivers power. At first I was delighted, then I touched the housing and burnt my fingers.

The radio gets very warm where the TIP36C is installed. At 70 degrees Celsius, after about 1 minute of transmitting, I stopped transmitting.

I set the BIAS currents of to 100mA, as specified in the service manual.

So I removed the jumper, turned it to the lowest level and then plus 100mA.
That did nothing. I checked the components behind the TIP36C and there is actually no fault to be found there.

The output stages are OK, I have desoldered and tested them, the TIP36C looks exactly the same on the component tester as a new one.

I'm a bit stumped now. Has anyone ever had a problem like this?

 

[Enterprise312ok]

The regulators run hot on those lincoln 2 + radios, I have never measured the temp but I have found they run a lot cooler with the rwob mod even with a pair of 100 watt finals.

 

[Ragon50ohm]

Thanks for the info. Which power amplifiers do you use for this? Do you need to make any adjustments to the output circuit?

The housing gets so hot that you can burn your fingers on it. No matter whether low or high power.