How to improve an old marantz pm-55

[edusub]

Hello everybody,

I just bought for a low price an old Marantz PM-55 not 100% OK but enough to perform some mods on it and fix it for a second equipment.

First question: what improvement could I get by changing the original ELNA caps 8200uf, 56V ? Which would be the best replecement for them (in an average budget, not spending too much)?

Second: I have noticed a crispy and intermitent cracking noise in the right channel, both in the two system outputs (PM-55 has exit for two sets of speakers). I have got the service manual but don't know where to look to find the origin of this default in the righ channels. Left channel in the two speaker sets work OK.

Thanks for any help you could provide.

Edu

 

[hew128]

Hi,

I have a PM-45 and sounds like same problem. Notice the cracking sound occurs more often when I touch the casing e.g leaking current.

Don't suppose you have made any progress on it since the post?

Thanks!

 

[east electronics]

the articular amp has room and step for a lot of changes how far and what to improve is only up to you

importand to notice is that improvemnts of any kind will alter the safety margins of the amp ...that is rule #1 and you have to live with that ...

then again improvemnts of anykind will have small percentage of benefit 2% here 3% there and so on ...importand is to think that 10 improvements of 3% each will sum to a result of almost 30% of total improvemnets ...so yes it worth the idea playing arround ...

schematic is available e mail me if you like to have it ... and following that i could give you a wish list of the things i would change or try ...

kind regards sakis

 

[hew128]

Took a while.

The issue caused by loose solder joints on the transistors on my unit.