NAD C370 Recapping, Repair and Service. (With Audio Tutorial)



Published
Fault
Low Audio on the right channel.
Complete recap required, multiple electrolytic capacitors reading high ESR low Value.

The video and Audio tutorial shows and explains the work carried out on this NAD C370.

Over the years it had seen extensive use.

The unit required a complete recap.
Nichicon Audio grade capacitors were installed for the signal processing sections of the Amplifier and low voltage power supplies.

Non Audio grade Nichicon capacitors were installed in the main power section due to physical size limitations.

As is always the case with Amplifiers of this time period the brown conductive / corrosive glue had to be removed before any new components were installed.

All the circuit boards suffered with multiple dry joints due to age and also heat.

The issue with low right channel Audio was due to the failure of Q801 2SK369 FET Short circuit drain to source. (Line in Module)
R220 499ohm 1/4 Watt as shown was also burnt out.

Replacing both components fixed the issue.

The user controls and switches were all cleaned with De-Oxit to ensure noise free operation.

The output offset for both channels was set to zero millivolts plus / minus 30 millivolts.

Idling current for both channels set to 5.5 millivolts

ISC Sensitivity set in-between to - 50 to - 100 millivolts.

Amplifier fully tested working correctly.
Category
Audio
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