McIntosh MC2100 - replace small signal transistors?

[THD]

If you want to challenge yourself than rebuild the multi-cap. It is time consuming.

View attachment 1313735

That's worth the trouble if it is a can that is on the outside of chassis that can be seen, otherwise like in the 2100, not worth it at all to me, lots of room to put an arrangement of caps to replace the old outdated cans in those, unseen. I cringe when I see those cans.

 

[Gregory]

I never got around to finishing this project up. I left it last January in working condition and had ordered a new multi-section can cap from Hayseed. That took a while to arrive and then summer happened and I got distracted with other house related projects. Now that it's almost winter I'll be getting back into this

-Matt

I used Hayseed multi-caps in the MC2505.




Waiting for delivery..







Was going to re-stuff the the originals.. but ended up with rings spinning around at the bottom of each can. Mechanical strength compromised.




Hayseed sent some empty cans to test fit.




One installed. Looked ok and it mounted tight enough. Quality good enough for me.



Requested that he NOT affix labels. Didn't like the looks of them too much. Didn't appear McIntosh enough.


Looking like new and in use every day.



Photos are displayed blurry on this board!


-Greg

 

[cdmawolf]

Just pulled out a MC2100 I had stuffed in a closet 8 years ago trying to "clean up" some stuff. I am trying
to remember what the status of all the closet items so checking them out. Not a stranger to McIntosh autoformer
SS amps I decide to start checking the outputs. All new MJ15003s but decide to check anyway. Did a whole
channel and no joy, they were all good. Started looking through this thread and say the comments about the diodes
and even though I had never seen a bad one I went ahead and checked them "in circuit". One channel was a dead
short. Hhhhmmmmnnnnnn....., I do not read something and then it actually happen.........Sssooooooooooo........
I disconnected the suspect side of the power supply and the diodes were good.......huh? Then I checked the BIG cap
and a DEAD short. Now that is a new one on me. I have read so many times that they NEVER go bad, but then remember
the dramatic fire show it put on when I first try to power it up real "quick".
Thanks for the thread and have a good week.

 

[mcgjohn]

might want to just do a general visual inspection for a cracked solder joint, especially if the problem changes with a change in operating temp.

 

[Gearjunky]

I used Hayseed multi-caps in the MC2505.

View attachment 1314780


Waiting for delivery..

View attachment 1314783


View attachment 1314784


Was going to re-stuff the the originals.. but ended up with rings spinning around at the bottom of each can. Mechanical strength compromised.

View attachment 1314785


Hayseed sent some empty cans to test fit.

View attachment 1314788


One installed. Looked ok and it mounted tight enough. Quality good enough for me.

View attachment 1314792

Requested that he NOT affix labels. Didn't like the looks of them too much. Didn't appear McIntosh enough.


Looking like new and in use every day.

View attachment 1314799

Photos are displayed blurry on this board!


-Greg

Great looking 2505!
I’ve used Hayseed in the past for a multicap for my mc2100 with great results. I’m in the process of a recap for my Mc250 and stumbled onto your experience with Hayseed. The other cap on your 2505 is a single cap, 500uf 50v correct? Did you have to make a special request for that? Also I noticed the Hayseed caps are now screwed into the chassis so I’d imagine you removed The rivets from the old caps? I emailed Hayseed for some guidance.

 

[eedork]

Reviving this old thread since I swapped the MC2100 in for an MC7300 and remembered how great it sounds. I'm going to finally replace the original filters with new parts from Mouser. They are getting expensive and I'm not sure how much longer they will be available, so now is the time to do it.

Question for everyone here - is it worth replacing the working original outputs with new MJ15003?

-Matt

 

[SaturationPt]

I replaced them in my 2105 because they were far apart hfe, but more important is the FSB that updates the driver boards so that they are less likely to melt down.

 

[eedork]

Thanks Jeff. I should do the driver updates as well. Did you source the parts yourself or use a kit? I've read here that McIntosh and/or AudioClassics had upgrade kits for the driver boards .. not sure if they still do though.

-Matt

 

[SaturationPt]

I bought my own parts, they were fairly easy to find as there is a thread (or two) here that has the part-list. Surprisingly the most expensive parts are the heatsinks. The update is easy to do before it melts down.

While you're in there the big PITA is the large emitter resistors, but they should at least be checked as they can cause damage if too far out of spec. They're wire-wrapped and soldered into the output transistor sockets, takes some patience to get that cleaned up if you need to replace them.