Novice seeks repair advice

joeyb

Member
2020-02-04 4:58 am
Hi All,

Long-time lurker, first-time poster.

I need to address a few issues on a Sony ES receiver from the late '80s.

This excerpt from the service manual purports to show the disassembly sequence.

rArkM1D.jpg


I assume the grounding notice means to attach a jumper from the rear panel to the board. But where on the board?

Second question: In the illustration, they have sketched in the heat sink running from front panel to rear. It is a very thin aluminum affair. I can see tranistors mounted to the side. Their legs pass through the board.

How does one keep the relation of these two parts while removing and working on it? Must you remove or desolder the transistors?

Thanks to any and all who choose to offer their help.
 

U230421

Disabled Account
2017-02-07 1:54 pm
But where on the board?.
A proper ground.
...a very thin aluminum affair... Their legs pass through the board... remove or desolder the transistors?

The thin aluminium affair (heatsink) keeps attached to the transistors and the board. Only when more thourough repair is needed, one can separate the affair.

While disassambling, you might notice arrows as to which screws should be removed while others keeps segments together.

As Ian formulated, the modelname/number is helpfull for further assistance.
 
Quote:
Originally Posted by MarsBravo View Post
A proper ground.

This does nothing to clarify the situation.

You are right.
It´s somewhat intuitive but here are 2 ways to find which of those many tracks and copper areas is the Ground.

1) since most anything is referred to Ground, it will normally be large areas of the PCB, often along one or more edges, and "going everywhere"

2) it´s usually connected to metallic chassis through one or more screws, bolts or (typically brass) metallic spacers.
Since disassembly physically opens such connection , they ask you to restore it by soldering a piece of wire from PCB ground area (which you just found) to some convenient spot on the chassis.
Probably some soldering lug or terminal.

3) if in doubt, post a copper side PCB picture, we´ll guess for you :)
Also another showing chassis and any terminals attached to it.

But again: looking closely you´ll find some point where a brass spacer joins (mechan ical) and connects (electrical) PCB copper and (steel/aluminum) chassis.