Saturday, 28 September 2013

YAMAHA A-1 NATURAL SOUND AMPLIFIER DIRECT DC , FROM 70's WITH LOOK Pt.I


Not working Amplifier, Yamaha A-1 all Black metal.
I'm almost sure it is broken or it has big trouble because the main cable is cut.


Yamaha A-1
So I start, open the case.....wath I find is...Dust


Dust inside..


I remove dust from jewel...

Yamaha A-1 inside, without dust!!
Inside A-1 demonstrate his particular design, Two Power Transformers and two big capacitors.
Power amplifer circuit is splitted on 2 boards+1 an 2 Big Heat Sinks.

The input and VAS stage is a full of components board, there is also an other little board(+1) only for to mount  the Yamaha double n channel JFET 2SK100

Yamaha 2SK100  Y-K100 JFET

Next Step: let's find trouble!!!