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Old 14th Nov 2019, 11:37 pm   #89
Sinewave
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Join Date: May 2016
Location: Oxfordshire/Bucks borders, UK.
Posts: 1,604
Default Re: Marconi TF144H/4S

Quote:
Originally Posted by G4XWDJim View Post
One of the tests and setting up procedures in the Marconi manual tells you to feed 2 volts into the output socket to calibrate the output meter. DON'T!!!!!

I did and it blew the thermocouple. There's a thread on here about it somewhere.
I've been giving this some thought.

There is no way I can calibrate the meter unless I do the above procedure.

Given all of the components I've replaced and the voltage which would be placed across TC102 under normal operating conditions, I couldn't see from my calculations how I'd damage the TC.

Following the procedure very carefully, I set the range control between two ranges, connected to the Direct Output with its switch on Normal and very carefully used a voltage calibrator to bring 2V into the unit. I then slowly adjusted RV103 until the meter sat on the 'set carrier' mark.

I have now successfully calibrated the level meter to read the 'set carrier' correctly.

I've just now got to sort the modulation out. Once I've done that, the level monitoring is sorted and then it's onto the rest of the set up procedure.
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