Is high tap an option on this machine? You might try that if cleaning your flippers doesn't provide the results you expect.

I'm not an EE, so not sure about how you phrased it, but probably.

Look at your transformer, gottlieb's had high and low taps labeled on the top lugs. there are a few threads here on Pinside with pics.

It can help, but is still secondary to well working flippers.