FG504/Repairs

Some personal recommendations:

• the red var-knobs should be handled with special care. Even isopropanol will damage the lettering.
• the big frequency scale seems also to be very sensitive. No isopropanol recomended.
• C1630, C1730, C1665, C1765 tend to get a high serial resistance. less than 1 Ω seems to be OK. For replacement I recommend less than 0.1 Ω. The manual allows up to 87,5 µF instead of the built in 50 µF. If there is a problem can be ckecked by doing the adjustment procedure stepp 4: Check Power Supply Ripple and Noise.
• the mechanical part 165 can develop whiskers. I recommend cleaning it with a metal brush and lacquer it. Lack will not stop the growing of whiskers but slow it down.

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  microscopic picture part 165

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  microscopic picture part 165