Yamaha CR 800 Problem

[kohoutek]

Hi

I have a Yamaha CR 800 which is only powering on, i cannot hear a click when switched on, all i am getting is power red light and the VU meter lights

I have connected a pair of Tannoy E11s and am getting nothing, tried the switching function, also a set of Grado SR80 Headphones, but still nothing.
Also an aerial for FM reception, but getting nothing, the VU meter for signal doesn't move too?

I am hoping to revive the receiver to its former glory and introduce it to

Philips GA212 turntable
Akai Gx210D Reel to Reel

then some 70s speakers

Any help would be appreciate thanks.

Michael

 

[avionic]

Know how to read a schematic?

No relay "click". Possibilities-

1. excessive DC voltage detected at the speaker connections.

2. Power supply issues

3. Protect circuit issues.

 

[avionic]

Page 17
http://sportsbil.com/yamaha/cr-800-sm.pdf

Check for DC voltage at the speakers by measuring the DC midpoint voltage (dc offset) using the test points as described in the procedure.

 

[avionic]

Welcome to Audiokarma BTW..:thmbsp:

 

[kohoutek]

Thanks Avionic

Never read schematics before, so going have to learn....lol
I have tested the points as described and yes i am a newbie to this too.

I have set my meter at 2V and am only getting .001 across TP3-TP5
and the same with TP4-TP6

Michael

 

[avionic]

OK. That tells me that the two amplifier channels are at least not shorted.:thmbsp:

Next we need to determine the serviceability of the power supply.

 

[avionic]

There are quite a few fusible resistors in the power supply. We need to see if the +12v is getting to the protect circuit via a violet colored wire. I am suspecting a dried up electrolytic capacitor or and out-of-tolerance fusible resistor. But can't rule out a possible bad relay driver transistor.

Pictures of the top and bottom side of the power supply would be helpful.

 

[kohoutek]

Avionic here are your pictures, thanks

 

[avionic]

That's just the power transformer. I need a photo of the power supply circuit board assembly.
Look at page 21 of the service manual.

 

[kohoutek]

Doh !!

Try again, told you i was a noob.......

 

[avionic]

Doh !!

Try again, told you i was a noob.......

Great photos. I do see a couple caps that look tired and overheated. On the bottom side of that board, note the purple wire. That should have the +12vdc
required for the protect circuit.

 

[east electro]

all of these capacitors should be replaced

Kind regards
Sakis

 

[petehall347]

Doh !!

Try again, told you i was a noob.......

the 3rd fuse along needs pushing back into the holder .. maybe you did this already ? if not it could be the problem .