MA5100 rebuild kit?

[tutor_turtle]

I have a nice, clean, original MA5100 on the bench for a total rebuild. Crackling in right channel after a few hours.
Other than that the sound is a little "thin". No noise, hum or buzzing. The controls are smooth and silent.
After 55 years the capacitors have surely perished.
I have seen one kit on eBay, but at almost $200, it seems a little pricy.
I have performed dozens of recaps on Marantz/Pioneer/Sansui. So I am comfortable with the work.
I have rebuilt a number of MC series tube amps. Those were fun projects that came out awesome.

So the basic question is: Do I change every cap? Do the film caps in this unit go bad?
If I delve into changing the transistors, does anyone have recommendations on substitutes?
There does not seem to be a bias adjustment, I would be reluctant to change the output drivers.
Any first-hand advice would be appreciated.

 

[clinic-audio]

Hello

Do I change every cap? no, it is not necessary , many members do a "recap" this is silly in point of view

Do the film caps in this unit go bad ? no , not to my knowledge

I don't know where you buy this "kit" but in any case this will not cost you the same price if you buy yourself

PATRICE working on MCINTOSH products since 45 years long

 

[tutor_turtle]

Thank you for your reply.
Electrolytics do have a finite lifespan.
Replacement is certainly warranted if I one sees leaking/bulging.
The multi-can caps seem especially short-lived.
I agree with your point on film caps.

 

[ramjet]

I have a nice, clean, original MA5100 on the bench for a total rebuild. Crackling in right channel after a few hours.
Other than that the sound is a little "thin". No noise, hum or buzzing. The controls are smooth and silent.
After 55 years the capacitors have surely perished.
I have seen one kit on eBay, but at almost $200, it seems a little pricy.
I have performed dozens of recaps on Marantz/Pioneer/Sansui. So I am comfortable with the work.
I have rebuilt a number of MC series tube amps. Those were fun projects that came out awesome.

So the basic question is: Do I change every cap? Do the film caps in this unit go bad?
If I delve into changing the transistors, does anyone have recommendations on substitutes?
There does not seem to be a bias adjustment, I would be reluctant to change the output drivers.
Any first-hand advice would be appreciated.

I strongly suggest you do a search on this site for the name of any eBay seller who lists a "kit" for any piece of audio equipment. The results may be enlightening......

That said, electrolytics do have a finite lifespan and they do warrant replacement. Leave the film caps and transistors alone and see how the unit performs after the power supply caps are replaced. My MA5100 never needed anything beyond the PS caps replaced.

 

[tutor_turtle]

I strongly suggest you do a search on this site for the name of any eBay seller who lists a "kit" for any piece of audio equipment. The results may be enlightening......

That said, electrolytics do have a finite lifespan and they do warrant replacement. Leave the film caps and transistors alone and see how the unit performs after the power supply caps are replaced. My MA5100 never needed anything beyond the PS caps replaced.

Very good advice. I totally agree.

 

[ivandezande]

I have a nice, clean, original MA5100 on the bench for a total rebuild. Crackling in right channel after a few hours.
Other than that the sound is a little "thin". No noise, hum or buzzing. The controls are smooth and silent.
After 55 years the capacitors have surely perished.
I have seen one kit on eBay, but at almost $200, it seems a little pricy.
I have performed dozens of recaps on Marantz/Pioneer/Sansui. So I am comfortable with the work.
I have rebuilt a number of MC series tube amps. Those were fun projects that came out awesome.

So the basic question is: Do I change every cap? Do the film caps in this unit go bad?
If I delve into changing the transistors, does anyone have recommendations on substitutes?
There does not seem to be a bias adjustment, I would be reluctant to change the output drivers.
Any first-hand advice would be appreciated.

I'd be a lot more worried about the transistors than the caps - the crackling.

But yes, every electrolytic should go. Leave films, unless you want to replace them, and then more power to you. Won't hurt, no matter what anyone says.

 

[Tala Mink]

I don't know about this kit, but I remember a thread a while back about a mcintosh recap kit that had incorrect replacements for the main screw terminal capacitors.

I agree with ivandezande that the issue is likely not capacitor related, bad caps usually cause distortion or constant noise, crackling and popping is usually caused by bad transistors or bad solder connections, especially if its only in one channel.

The unit should at least be partially recapped though, I have worked on two 5100's and a multican was dead on both, the axial mallory's don't age well either.