Marantz PM4400 Amplifier

[seanww69]

Hi all hope you can help, I have just acquired this amp from a mate but seems to have a problem when you switch it on everything works fine then after 20 seconds it switches itself to mute. Does anyone know what this fault maybe as i dont have a remote control could this be the problem
Waiting in anticipation to hear from the experts.
Kind regards
Sean

 

[jaycee]

Hard to say by this alone... does it seem to be getting very hot ?

Could just be a faulty power-on mute circuit... but without further testing it's not really possible to tell.

 

[seanww69]

Hi Thanks for reply no its not getting hot at all.
I will have a look at the circuit to the mute switch.

Thanks
Sean

 

[anatech]

Hi Sean,
Check for DC offset on the emitter resistors that may trip the protection. I have seen leaky transistors in the protection circuit cause false tripping. They will be TO-92 style.

Do you have a schematic? With one we can give you more detailed help.

-Chris

 

[seanww69]

Hi Chris

Thnks for your valued reply i have checked and have leakage in two areas which has dried up looks like glue
areas affected power supply part and r-ch l-rc
I dont have schemantic unfortunatley
Hope this makes it a bit clearer
Thanks
Sean

 

[anatech]

Hi Sean,

Thnks for your valued reply i have checked and have leakage in two areas which has dried up looks like glue

That stuff is evil. Make sure you remove all of it. Inspect all component leads it may have touched as it can be corrosive as well.

This may solve your problems.

-Chris

 

[tricomp]

Hi Sean,

Did you ever fix it?

If you need the Service-Manual I have it. Give me a yell if you want a pdf-copy 😀

Kind regards,

/tricomp

 

[seanww69]

Hi All

Sorry not replied been on Hols, thanks for your offer of the service manual i have given up cleaned all the leaking caps but still no joy.

Am i am a blundering novice when it comes to more tech stuff so i have let it alone.

Thanks again gus for al your help

Regards
Sean

 

[jaycee]

tricomp, mind if i grab a copy of that service manual?

 

[tricomp]

Hi,

No problem.

Give me your e-mail address and it'll be on it's way 😀


Kind regards,

/tricomp

 

[jaycee]

ok my e-mail button is now on 🙂

 

[anatech]

Hi tricomp,
May I join the "me too" club? Large attachments go to bhomester at gmail dot com.

Jaycee, the forum email only allows tricomp to contact you. You would then reply to him with your address.

-Chris