NSM Festival ES-160 Problems

[packrat79]

  I'm working on this unit for a customer.... I've never worked on an NSM before and I'm finding this one to be quite a challenge. The main problems it had, on arrival, were no sound and the player mechanism jamming during loading. Since a service manual was not readily available, I went to work on the player mechanism on my own, and after a few hours of work finally got it functioning properly. A previous "repairman" apparently had taken it apart and put it back together wrong - it took some figuring to correct his mistakes. So anyway now the player mech works fine, but there are two other problems which could be really hard to fix without a service manual:
  1. No sound
  I can touch my finger to one of the preamp modules and produce a loud hum on the right channel, so I know that much is working. The left channel output transistors were blown, and I've removed them from the circuit. It appears that the muting is NOT turning off when the record starts playing; when you first power the unit, you can briefly get a good clear sound from the record, before the mute relay kicks in. Is it possible, that the mute circuit remains activated if there's a problem with the amplifier - even on one channel only?
  2. Turntable speed very low
  When a selection is made and the mech starts scanning, the turntable motor spins at it's normal speed. Once the record is loaded and the scan/load motor shuts off, the speed of the turntable motor drastically decreases (at the exact same moment, as if it were piggy-backing off the power supplied to the loading motor). This one is a complete mystery to me.
  If anyone can give me some tips, or direct me to a source for a complete service manual (including amplifier schematics), I'd appreciate it very much.

[Ken Layton]

The manufacturer is at www.nsmmusic.com