Need SB-620 advice

[Daniel Ruth]

Well I finally brought my HO-5404 back into service.  The SB-620 is
losing its "fish finding" capabilities.  Even at full PIP GAIN, only
strong signals are registered; the HO-5404 is detecting all signals (even
weaker ones) much better.

Has anyone had similiar problems and successfully found the components
that need replacing/checking?  This SB-620 used to work as well as the
HO-5404, so something's deteriorated.

Happy 4th,
Danny (W3ZF)  heathkit at juno.com