MEP-804B putting out only 50HZ

I checked the MPU as recommended from a friend and it's 2.5 and the switch is set to 60HZ. It ran fine half way thru Milton running AC pool pump and everything else fine. All of a sudden the AC fan outside was running slow. I checked the frequency and it said 50HZ. While running, it pops up for a split second to 60 or so. My friend thought it was surely the MPU. The PEC potentiator behind the frequency knob is corroded. Nothing else on the machine shows any corrosion like the PEC pot. I ordered a new potentiator and will solder it on this week. Anywhere else I can look? FWIW the only reason I know about the MPU is the info from a friend. I'm pretty good mechanically but electric can be trying. Jerry

Welcome! Any photos?

All the best,

2Pbfeet

What position is Item 27 in?

2Pbfeet said:

Welcome! Any photos?

All the best,

2Pbfeet

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Yes. The voltage potentiator is just as bad

Guyfang said:

What position is Item 27 in?


View attachment 946951

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G

Caliglas said:

GView attachment 946954

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60

I believe I would start here. Good eyes. I might try de soldering the R1 and then cleaning the terminals up. Then re-solder and give it a try. The funky terminals may be making contact to the control panel door.

Yes funky is appropriate. I have a new one coming in tomorrow. I might get another for the voltage too. I’ll let you know inna few days. Thank you