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Old 10th Dec 2018, 9:58 pm   #16
mole42uk
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Join Date: Aug 2010
Location: Resolfen, Wales; and Bristol, England
Posts: 2,588
Default Re: Gould 407x display help

Another update: having replaced the 120V zener I now have that supply rail working, and having found the pictured dead transistor and replaced it and the 100R resistor in the supply rail, I now have the 270V woprking again.

There's still no display on the screen, the brightness controls do change the voltage to the bright-up circuit but there's still something wrong in there. It's not made any easier because the layout diagram I have is only a little similar to the PCB I'm working on. This means that every time I need to check a component I have to find out which one it is by tracing the circuit layout on the board. Tedious, yes it is.
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