Chris van Lint
I recently tried to fire up my FG502. The unit was not working and the green power lamp was not illuminated. I discovered that one of the 741 opamps in the power supply was faulty. I replaced the 741 and the unit now appears to be working OK. However although the +20V supply is within specs, the -20V is way out at -30V. The +20V supply is easily adjusted with R625, but I cannot find any adjustment pot for the -20V supply. _The +17V and -17V supplies are also within specs._
- Does this mean that I should not be concerned about the -20V being too high?
- Am I correct in assuming that R672 on pin4 of U664 is out of range?
Any advice would be appreciated