Fisher K-10 Spacexpander - Hum Adjustment; Unit Fails to Power On; Audio Output Problems; Reverberation Issues

exposure to too much heat or a chemical reaction to fumes, aerosol sprays or furniture polish.
Replace rubber grommets if they have become hard or gummy
HUM ADJUSTMENT -The Spacexpander is adjusted at the factory, but after continued use, or
changing a vacuum tube, it may be necessary to change the adjustment:
To check for minimum hum.
• Set the home music system input SELECTOR to an unused position .Disconnect one pair of plugs
if all jacks are used.
• Turn the BASS and VOLUME controls to their maximum clockwise positions.
• Insert a screwdriver through the opening in the Electronics Chassis marked HUM ADJUST
• Rotate the shaft of the HUM ADJUST control for minimum hum from the speakers.
Does not go on (tubes do not light up).
Check: • AC outlet (use test lamp).
• Line cord and plug.
Distortion (both channels) any position of MODE SELECTOR switch,
Hum, Weak or No audio output (Tubes light up.)
• Disconnect Spacexpander temporarily (reinsert jumpers) to be sure that other
components of home music system are operating normally
Check : • HUM ADJUST control R11.
Test : • V3
• Power supply for voltages at CR1, C5A R9; C5B, R9, R10; C5C, R10, R12; C5D, R12. V3
socket for proper voltages.
No reverberation (both channels) no audio output in REVERB ONLY position of MODE
SELECTOR switch. Hum, Weak or No REVERB output.
• Listen to voice -comedy or news
• Set Control Unit knob to MAX position.
• Push Control Unit knob down.
Check : • Control Unit plug and interconnecting cable.
• Reverberation Unit jacks, plugs and interconnecting cables
• R24 and S1 on Control Unit.
Test • V1 and V2.
• V1 and V2 sockets for proper voltages
No reverberation (PHONO-MONO only)
• Check phasing of phono cartridge.
Reverberation only (no pure signal) any position of MODE SELECTOR switch.
• Set MODE SELECTOR to NORMAL position.
Check : • S2 for proper operation.
• Control Unit jack, plug and interconnecting cable.
• R24 and S1 in Control Unit.
Feed back (when system volume or Control Unit knob turned up.)
Check " • Shock mount assembly