Marantz 1070 relay will not click

[AngelAT]

Hello everybody!

I am currently working on a Marantz 1070 - European model. I bought it not long ago. My problem is that the relay will not engage.

What I have done so far:
-PSB 40 VDC
-H1 to H4 checked - OK
-H705 & H706 replaced with 4148 in series
-H726 and H727 replaced
-C721 and C722 replaced
-H701,702,703 &704 replaced - one in each pair was defect
-C701,702,705,706,719&720 replaced
-Relay (OMRON MY 2) coil 650 Ohms
-Idling current fixed to 10mV
-Bias 0V
-Signal goes to the power amplifier (P700)
-Relay looks ok visually

Please help, I am out if ideas...

Thanks in advance and stay safe!

 

[avionic]

-Idling current fixed to 10mV
-Bias 0V

Idle current is the same thing as bias.

DC offset is OV
Bias/idle current is 10mv

 

[avionic]

I would say trouble shoot the protect circuit and/or the power supply for the protect circuit.

 

[AngelAT]

I would say trouble shoot the protect circuit and/or the power supply for the protect circuit.

Thanks Avionic for the prompt reply!

You are right - a mistake for being frustrated and in a hurry.
I have checked J808 and J809 and they are -33,6 and +33,6V
I have checked H725 (ok), replaced H726,727 and 728 and C721,722.

What else should I check?

 

[avionic]

What is the collector voltage of H728 ?

 

[AngelAT]

0,78 v
Suddenly when I was measuring it, the relay engaged...
Very odd...

 

[avionic]

0,78 v
Suddenly when I was measuring it, the relay engaged...
Very odd...

Inspect the solder connections for H728.. Or you accidently shorted the collector to the emitter lead.

 

[AngelAT]

...and I have sound!
Maybe I did not solder it well...

 

[AngelAT]

Inspect the solder connections for H728.. Or you accidently shorted the collector to the emitter lead.

Thanks Avionic!
This was a quick fix!

Stay healthy and safe!

 

[avionic]

I like happy endings..