Late model "silver face" Marantz receiver. Loosely related to the similar models 1515, & 1530. Taiwanese-built, from 1979. Found with main power fuse missing, & internal driver fuse open. Discovered 1 shorted bias diode, along with a shorted driver transistor. Ran ok with these shorted components removed, but was still smelling hot & tests showed unit was still drawing too much current. The additional culprit suspected, then proven of contributing to the failure was the National Semiconductor LM391N-60 Op Amp/Preamp IC, Q702. Located upstream.
5 авг 2024
