MC2505 catastrophe

[Benz]

You're right. Cool that they still had those pots in the 90s. Are those replacement MAC pots even available now from the parts dept?

Benz can you post photos of your input jacks?

Here are a couple pics. The jacks are nice and solid, no play and no grounding issues.

 

[Celadon]

The invoice shows p/n 134210. According to the SM, the gain pots are p/n 134-187. The trim pots on the input board and the meter board are p/n 134-120. Based on that, and the low price charged on the 1996 invoice ($24.70CAD), I'd be inclined to think that it's for 2 trim pots and that they somehow messed up the p/n by inverting the "2" and the "1". Just a guess, but I don't see an original Mac gain pot costing only $12CAD even in 1996. To be honest, all 4 trim pots look pretty original to me so it may have been another case of "creative" invoicing, like they did with the 2 extra caps that never got installed.

Makes a lot of sense -- well confusion actually, but I understand what you say -- especially with their creative invoicing .....

Yes even in 1996, $12 seems way to cheap for a gain pot from McIntosh.
Around 2005, I was reworking my C26 --and the volume pot had an imbalance (fairly well known issue) that pot is also the power switch on the C26 -and I remember it being $75.

Thanks for the pics of the input jacks

 

[Celadon]

That repair shop in 1996 added a nice bit of markup on the glass. $200 back in the mid 90s is probably the inflation adjust equivalent of close to $400 now.

Looking at a CPI Inflation Calculator they say:
$200 in 1996 is worth $386.70 today, USD

 

[Benz]

Finally received C33! It didn't ship right away, was stuck at customs for a week and then was delivered to the wrong mail box. Sometimes stars don't align... but it's here now and I should be able to install in in the next few days.

 

[Celadon]

Glad you finally got that cap "out of jail" -- yeesh Delivery issues for things here have been really sucky - as well.

 

[Benz]

C33 is now installed and all is well, temps are good and the amp is working perfectly. I've decided to keep C29-C30 (big caps) as they test and perform fine. They would cost me over $400 CAD with shipping and fees, so I won't replace them unless I have to. They are also very easy to swap and I can do that at a later date if needed.

I'm thrilled with the results and want to thank the AK community once again for helping me accomplish what I would certainly not have been able to do on my own otherwise.

 

[Benz]

Now to wrap up the story, a few "show and tell" pics because... why not!

Hoping not to have to remove this bottom cover again for many years


Back in its slant leg wood case


In all its lighted glory


The MX112 it will be reunited with shortly (shown here with cousin Mac1900 below)


Back home


All original, mint documentation for both the amp and the preamp/tuner:
- Owner's manuals,
- Service manuals,
- Warranty/service certificates,
- Service request card,
- Panloc brochure,
- Original bill of sale incl. trade-in (Fisher 600T receiver). Nov 1968 cost was $899CAD for the MX112 and $679CAD for the MC2505. (somewhat suprised to see the preamp cost more than the amp)
- Repair/restoration invoice for work done on the amp in 1996


And that's a wrap!

 

[monkboughtlunch]

Great job @Benz

 

[Celadon]

Benz -- Pretty doggone impressive, and awesome work too.
Happy Listening.

Celadon

 

[monkboughtlunch]

I was inspired by this thread to finish up my MC2505-2.

Tonight, I replaced the four filter cans in the power supply. I replaced C79 with an axial. The other three cans were direct can replacements.

The CDE main filters had 2022 production dates, fairly recent. The CE Manufacturing can was made in 2023.

This sure is a sweet sounding amp.

If it's helpful for others finding this thread in the future, I used these parts. My 2505 was manufactured in 1972.

• C79: Vishay 680 μF 63 V 126 ALX Part # MAL212618681E3
• C33: CE Manufacturing 250 V, 150/80/80/50 μF Part # C-EC150-80-80-50
• C29, C30: CDE 15,000 μF 75 V Part # 066405

 

[monkboughtlunch]

For C33, note that CE Manufacturing uses a different shapes / sections for their replacement can versus the original GE can. So you can't go by the shapes and swap wires just like the original. You'll end up having to re-route the wiring to that can a bit as a result. The orange wire has just enough slack to make it to the new section position. Other wires will have additional slack as a result of the change.

I made these notes when installing the new CE can.

Original General Electric C33 multisection can wiring:

• Half circle – 80 mfd RED wire
• Square – 80 mfd BLUE wire
• Triangle – 150 mfd ORANGE wire
• Dash – 50 mfd RED/WHITE STRIPE wire
• CAN – BROWN wire

New CE Manufacturing can wiring:

• Half circle – 150 mfd ORANGE wire
• Square – 80 mfd RED wire
• Triangle 80 mfd BLUE wire
• Dash – 50 mfd RED/WHITE STRIPE wire
• CAN – BROWN wire

 

[Benz]

Well done Monk, and great additional info!