• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Retube on a mac ma-5100

Alguymcgee

Alguymcgee

Active Member
Hey everyone,

I was presented with an opportunity to pick up an MA-5100 for relatively cheap, but it's still toward the top of my price range. Just curious, if it needs a retube, what would a reasonable cost be? I k is it varies based on location and bench fees, so I'm just looking for a ballpark figure here. Thanks!
 
Register to hide this ad
Can't help you on that, I did my MA-6200 myself.

If you are good with a soldering iron and can read and understand the parts values and polarity on the caps, a recap is not very difficult, just move one at a time, tracking what has been done and what hasn't.
 
How and why? Facts here. And I am sitting in front of a McIntosh MA 5100 integrated. It has no tubes. It is solid state, all transistor. The second McIntosh product to be so, the first being the C 24 preamplifier.
 
Haha yeah yeah I'm still learning. I'm really just asking what is reasonable to spend on a full recap would cost. I plan to learn how to do that on my own, but I'm not willing to learn on a mac
 
The big electrolytics seem to age OK on the MA 5100, the smaller ones are where I'd focus. And do keep the soldering neat and precise, the people who built this took pride in their work.
 
I just picked one up for $200. Haven't even hooked it up yet but the seller said it works well for an hour and then shuts off but instead of troubleshooting the one problem, I figure recapping would be a good idea. Hopefully it's a capacitor issue and not something else. Looking at the service manual, there aren't very many electrolytics to replace. Only 11 small ones that should be easy to source. Kent says not to worry about the big ones, but it seems like after 47 years (original owner purchased in 1971), it may be a good idea to replace them as well. Where do I source the 2 large 9300 ones and the 3 multivalue cans or should I just do the small ones and see how it works? Any advice would be appreciated.
 
biggal76 said:
I just picked one up for $200. Haven't even hooked it up yet but the seller said it works well for an hour and then shuts off but instead of troubleshooting the one problem, I figure recapping would be a good idea. Hopefully it's a capacitor issue and not something else. Looking at the service manual, there aren't very many electrolytics to replace. Only 11 small ones that should be easy to source. Kent says not to worry about the big ones, but it seems like after 47 years (original owner purchased in 1971), it may be a good idea to replace them as well. Where do I source the 2 large 9300 ones and the 3 multivalue cans or should I just do the small ones and see how it works? Any advice would be appreciated.
Click to expand...

I'd fix before recapping. Too easy to introduce new issues by accident and then you've got multiple things to chase down.
 
Cat,
so I guess you aren't thinking it's not just be a failing capacitor? You thinking output transistor or what? Any chance that since values of components have changed over past 47 years, bias could be off and causing overheating and shutdown and all I'd have to do is reset bias? Guess I should hook it up and witness the issue myself before making too many assumptions.
 
You really need to do some diag before condemning anything.

Working for a while and then going out can be as simple as a bad solder joint that loses contact once the unit warms up. Could be a failing device also.
If the bias is way too high it might go into thermal protection so that is something to check as well but be careful with older open frame pots as they can be touchy.

Not saying you don't have worn caps but I doubt that they are causing your issues.
 
I agree with others. While replacing caps may be in order due to age, I think it is not that often aged caps are the root cause of a problem like described.

Identify and fix the specific problem rather than hope a shotgun blast hits the mark.
 
So I finally found some time and hooked it up. One channel out, both channels have a little hum. Was going to assume needs lots of work and put on Ebay for parts but decided to clean the controls and see what happens. Cleaned them, turned it on for over an hour and a half and worked and sounded great. I guess it just needs new lightbulbs. I'm psyched.
 
Sounds pretty good but bass is not even-certain frequencies a little boomy and others are barely audible. Also, bass drops off down low and it's not my speakers (modded Klipsch Forte II). Specs say it should go below 20Hz with pretty much flat frequency response. Doesn't even come close to my tube system but it probably never will. I don't even like it as much as my Pioneer and Sansui monster receivers. Would recapping the small ones likely remedy my issues or is this just how they sound?
 
I'm going for it-replacing small electrolytics. Ordering this evening. Should I do the tantalum electolytics as well? Anything else I should replace?
 
You must log in or register to reply here.
Back
Top Bottom