I have a Marantz PM4000 amp which cuts out (mute light starts flashing) when playing above 1/4 volume, particularly with high bass tracks. The loudness button is not pushed in and bass control is set to it's midpoint.
Is this a common problem? When I bought it 4 years ago, it could play louder than 1/4 volume and I have not changed any of the setup since then (same cd player, speakers, cables etc). Guess it is a technical problem?

Does anyone know what the problem might be?

Grateful for any advice.

Thanks,

Stuart Milne

I recently experienced the same problems reported by Stuart. I was hoping someone could advise me on a replacement amplifier (I am looking at the Marantz PM72000). I am new to this forum and have found the advice offered really helpful. If anyone can advise on the suggested amp that would be great.

Same here - same amp (PM4000).
Obviously Marantz have a common fault here and really aught to fix for free.
I do intend to buy the 7200 having auditioned it.
The class A mode is superb.

Same amp, same problem. Mine has had this problem for about 18 months. I did manage to find out that it is a known problem with a simple fix that can be done by anybody nahndy witha soldering iron (got this info from another person with the same fault!), but emails to Marantz didn't get any joy.

I find that the problme is not apparent when mine is thoroughly warmed up so I never turn it off and it isn't a problem then even at high volumes.

Ian

[PHENOMENON]
The MUTE LED sometimes blinks and the sounds from output is intermittent.

[CAUSE]
Contact error between the bracket (Pos. No. 30) and the ground of INPUT/AMPLIFIER PCB (Pos. No. 29).

[SOLUTION]
Contact to the ground certainly by the wire with the lug. Please refer to the processing figure of the next page and correct.

[NECESSARY PART]
The wire with the lug: (MJI Part No. YB00091620 or similar product)

[REMARKS]
This improvement has been done in the production line after.
The serial number MZ000149006651 and later. (PM4200/N1B/N2B)
The week code number MZxx0203xxxxxx and later. (PM4200/N1G/N2G)

I have a pdf of the official fix attached:

Many thanks for a fix that I have been looking for for a while now.

What I need to know now is, how do I get hold of MJI Part No. YB00091620?

Cheers

Het guys.
Thank you very much for posting this. ive had this problem for about 2 years now.
THANKS!!!!!!!!
i hope this works *G*

ill try it later

peace

I did the modification, amazing that such a terrible long term problem was fixed with such a simple modification.
Thanks guys.
+karma

Lope

Hi i have this problem too. Where would i be able to get this part from, or someithing similar. Is it just a copper wire? cheers

Looks simple enough. Will ordinary coated copper wire do the trick do you think?

Yes, but use solid / single strand cable rather than multistrand if you can get it.

It's much easier to work with in such a small space and you are less likely to cause any shorts as there are no stray strands to worry about.

Thanks a lot MJB. I'm not even sure that this is the problem but I've tried everything else so I am confident it will work. I'll post to let people know .

This forum brings home to me everything that is great about the internet. Fast solutions to the little questions & problems you would otherwise have to live with!

Thanks again.

Thanks 4 this Exmind- had exactly same problem with unit purchased 2001. Easily fixed by local repairer. Interestingly official repair Co. claim to have never heard of problem!

The PDF that's linked is corrupted. Does anybody out there have the diagram still???

Hiya... Newbie here.

It's an old amp I know... but I just bought it off ebay... was working fine, but now it's having this exact problem. I'm handy enough, I'll attempt to fix it myself... But like the guy above, that PDF won't open for me.

I'm desperate... all help or suggestions greatly appreciated.

Cheers...

Strange how some people are having problems with the file.

I've uploaded another copy here. See if that is any better.

Yep... that works.

Cheers Mate... Champion!