Wednesday 10 August 2022

NAD Stereophonic Amplifier Restoration (1973)

 NAD Service 9 Aug 2022

Approximately 7 hours work.

I don't count.

Full cleanup, contact cleaner, blow dry.

Replacing 13 electrolytic capacitors.

6 800uF with 10 000uF on split power supply. (Had to drill some holes.)

Replaced germanium bridge diodes with 1N5408 3A 1000V

Replaced 2N3055 output transistors with RCA (to match 2N2955 and due to corrosion.)
Re-calibrated power meters.

Glued mains broken socket. (Did not try to get a new one).

To do BIAS and DC offset adjustments require soldering resistors on the back of the board.

I will check the current values. If they are OK then I won't delve into that as well.

It's quite a laborious task. Let's not split hairs.

Full check... Especially decoupling resistors for differential input stage.

The Amplifier is done.



















After