MC2205 speaker relay/fun with Gregory

[jbailey930]

Morning - I had the pleasure of local AK'er Greg stopping by to look at my amp yesterday. There's been a left channel drop out for a while. Been intermittent and so we decided to lug the beast off the shelf and go after it.

Greg is well versed, search for 2205 love thread. He came over with new set of caps and his kit. We cleaned and worked the rear switches thoroughly. Replaced the caps on the driver boards. Checked all the solders, cleaned the pins, lubed and cleaned the spades to relay. It was a great experience watching Gregory work on the boards. Unfortunately, the problem persists and I am in need of a new relay. I'll call McIntosh later today - and appreciate suggestions for supplier. I need to do the power guard bulbs too, so more to come.

 

[Gregory]

Yeah, that was great way to spend a Sunday afternoon. You've got an excellent AV room and workshop.

Use the search strings below to find the parts, and part numbers for: a) speaker relay, b) power meter and power guard lamps, c) meter lamps (8 total).


Buy the speaker relay from Mc for what.. 60 bucks? or find the Potter & Brumfield number and spend 16 bucks:

https://www.google.com/search?q=2205+Potter+Brumfield+relay+site:audiokarma.org

https://www.google.com/search?q=2205+Power+Guard+lamps+site:audiokarma.org

https://www.google.com/search?q=2205+meter+lamps+site:audiokarma.org


This is what John posted (from search above):

"I used.. Tyco/P&B KUP-11D55-48 relays in my MC2200 and 2205 and they worked perfectly. This is the same manufacturer and series as the original except the McIntosh version uses the "bracket mount clear case" that has slots for screws. You can either swap the covers between the old and new or (as I did) use some heavy duty scotch double sided foam tape to hold it to the chassis. The terminal orientation is identical to the original except the new relay has an extra row of terminals across the top that you can ignore. On the Mac part this extra row of terminals is cut flush to the body and not accessible. The terminals on the new relay may be very slightly narrower than the original which may require you to slightly crimp the female connectors on the mating wires for a snug fit. I had no problem and as I said, the relay works perfectly. It's only $15 and they are in stock."

http://www.mouser.com/search/ProductDetail.aspx?R=0virtualkey0virtualkeyKUP-11D55-48


-Greg

 

[Mike Gibson]

Sounds like it was a fun time for both of you. I hope you get it sorted out soon.

 

[Gregory]

Sounds like it was a fun time for both of you. I hope you get it sorted out soon.

Not sure if it was so much fun, but it was definitely productive!


Have taken the liberty to rotate and scale John's photo 2x.



The P&B part number seems to be: KUP-12D56 , 36 VDC coil.

I'd find one on Mouser that matches the specs: 3-pole, 1 (or double) throw.


Be aware.. the relay I bought had narrower spade terminals than the original push-on spades.

-Greg

 

[Gregory]

John said he already ordered a relay but didn't say from where.

I had looked into 2205 relays and came up with the following:


This was the ORIGINAL relay in my 2205. P/N KUP-12D56 .. 36V




This was the RELAY I ordered from McIntosh Parts for 60 bucks. P/N KUP-12D55 .. 36V


It has narrower QD terminals that the original, so I ordered and attached new spades.


Here is the MC 2205 Power Supply schematic, where the Relay is across the 42V rail.


Click image to go full scale.


Will have to see what John came up with for a relay.


-Greg

 

[sKiZo]

You doing road trips now? I got one waiting here! I'll put the kettle on! <G>

My MC2205 is long overdue for some TLC. Plan was to build a kit tube amp to keep me happy while the Big Mac was on the bench, but the tuber sounds pretty spectacular and there hasn't been much incentive to drag the beast into the basement. These ol' bones start to pop and creak just thinking about it. ;-}

Still works, so maybe I'll switch the wires and give it some exercise today ... cold and snow today, so good day to stay in anyway.

 

[kevzep]

Not sure why they sell you one with narrower terminals, I bought two from mouser (I think), they had the same width terminals as the original, although slightly thinner, which was fine with me.....
I'll dig my spare out and get the part number...

 

[jbailey930]

You doing road trips now? I got one waiting here! I'll put the kettle on! <G>

My MC2205 is long overdue for some TLC. Plan was to build a kit tube amp to keep me happy while the Big Mac was on the bench, but the tuber sounds pretty spectacular and there hasn't been much incentive to drag the beast into the basement. These ol' bones start to pop and creak just thinking about it. ;-}

Still works, so maybe I'll switch the wires and give it some exercise today ... cold and snow today, so good day to stay in anyway.

yeah, you need to Greg out there for his skills! Keep these beasts humming like new if not better.

I called McIntosh and hope to have the relay by the weekend. The N'Easter Stella storm may impact shipping, My sis in NE Pa got 25 inches of snow Tuesday and I heard Binghamton got 31 "

 

[Gregory]

You doing road trips now? I got one waiting here! I'll put the kettle on! <G>

My MC2205 is long overdue for some TLC.

Am I doing road trips now?

Ha, drove cross-country out to California and back twice in recent years and have a `standard car-load.´ Even ran into Ron_C in Santa Clara at an Mc event. If you want me to come out, you'll need to provide some coffee, oat meal, (we'll do lunch), chow for dinner and a place to park my sleeping bag. Lol

No really, the standard x-country travel day in the Buick is 650-750 miles depending on speed limits, from 6 or 7 AM to 6 or 7 PM. It's 660 miles out to Summit Avenue NE & Rt-131, and 10 hours driving. That would require 23 gallons of fuel (~60 bucks) each way. Maybe c_dk could come over. Do you know what parts you need? Could probably do everything in one day. So one day travel, one day for updates, and one day for return trip.

Just doin' a feasibility study right now.

-Greg

 

[sKiZo]

Just joshin' wit ya ... put that feasibility away ... you could poke somebody's eye out with one of them things! <G>

Truth be told, I already got all the parts, just not the ambition, or truthfully, the need ... right happy with what I'm hearing right now on the tube system.

Then again, maybe I need to get my ears checked, right?<G>

 

[Gregory]

Was thinkin' the other day..

Has anyone been able to replace the PG and Meter Mode lamps without taking the front panel off?

Here's a view looking down into the right side of the meter compartment.. or under the meter cover.




Here's another view. Notice the machine nuts and lock washers that could be reached with a 1/4" drive socket wrench?




The issues could be.. is the ribbon cable in the way? Can it be disconnected in that tight space? How much will the 40-y/o ribbon deteriorate from flexing and handing it?


Maybe John would like to remove the glass panel to inspect / replace the foam tape in there?


-Greg

 

[Gregory]

Not sure why they sell you one with narrower terminals, I bought two from mouser (I think), they had the same width terminals as the original, although slightly thinner, which was fine with me..... I'll dig my spare out and get the part number...

Any luck finding the P/N?

This is the relay Mc Parts sent. Hey you gotta' call 'em out on these things instead of bowing down.



To do a good job, I ordered new spade terminals of the correct size.. plus they were new and shiny.

I considered lap-soldering each wire on top of the relay lugs.


-Greg

 

[kevzep]

Any luck finding the P/N?-Greg

Ah yes, well, I moved house 6 months ago, now I know I saw it the other day and I can't remember where......
It's not where I thought it was....

I will find it and post the P/N when I find it...

 

[jbailey930]

Ah yes, well, I moved house 6 months ago, now I know I saw it the other day and I can't remember where......
It's not where I thought it was....

I will find it and post the P/N when I find it...

No worries! I ordered from Mc already. We will see if the spade connectors are the same size that we have on the original unit. Unfortunately the winter storm impacted shipment. McIntosh was closed Tuesday and Wednesday. So this project may be delayed a couple of weeks

 

[lbcgav]

KUP-14D15-48 is the relay I used.

 

[jbailey930]

Another good afternoon spent with @Gregory addressing newly found issues. Bias may be off as right channel heat sink measured 76F while left measured 95F - noticeably warmer to the touch. He will show me how to adjust bias when this is buttoned up.

Apparently some work had been done on the PCB -




Greg provided part numbers earlier in the week since we were going to take the front panel off for the Power Guard bulbs and meter lamps. He mentioned this is a great time to update these caps. My Mouser order won't arrive until mid-week Looks like someone hacked this fix. Fortunately, Greg had spare diodes (you should see the kit he brings over!).
-
AFTER -


New caps on meter board -

 

[jbailey930]

Some good progress since the parts arrived this week. Greg was gracious to solder in the caps on the PCB.



I replaced the relay. I'll post pix of the old relay to show the wear. The spades fit good. Greg says the new relay connectors are about 10 thou thinner than the old. I replaced meter bulbs and did a "soft" reassemble to try out the updates. I had a feeling the fixes to the diodes and caps that the PG / Normal lights will restore them, and voila they do. Greg is going to setup a dummy load to test PG function once we get fully satisfied on the updates. I did a little listening at normal volumes in my shop with JBL L110s. Great soundstage and imaging . I noticed this pic shows one light out on left meter. Turns out they need to be seated correctly on the rail to light!


Once again, great thanks to @Gregory for his patience and expertise!

 

[jlovda]

Just for your information and also to future "re-cappers," the electrolytic cap closest to the center of the power supply board controls the timing of how fast the speaker relay closes. It is not in the audio path. Don't fiddle with the value.

 

[Gregory]

It's really a fun project, and I think John is satisfied with the tech advise and results so far.

The first weekend over John's place, I forgot to bring the new SX710 camera. The next weekend, being in a rush, we took off and left the camera battery in the charger, in the wall socket. Rrrr! - no pics for two straight weekend!


This photo (from the third week) is of the Relay that Mc Parts sent to John:




The lugs are: 0.187 x .020 QD.

Below are my notes from 6-3-2009 updates on the 2205:



The table, above lower-right shows the Original and New relay lug sizes in my case, rev 6-7-2009.


These are the New replacement terminals to fit the Factory replacement relay, ordered from McMaster IIRC.






Nothing wrong with new, shiny terminals!

John says the Original terminals fit on the New relay lugs just fine. I'll have to believe him but check for sure.


-Greg

 

[Gregory]

Some good progress since the parts arrived this week. Greg was gracious to solder in the caps on the PCB

I replaced the relay. I'll post pix of the old relay to show the wear. The spades fit good. Greg says the new relay connectors are about 10 thou thinner than the old. I replaced meter bulbs and did a "soft" reassemble to try out the updates. I had a feeling the fixes to the diodes and caps that the PG / Normal lights will restore them, and voila they do. Greg is going to setup a dummy load to test PG function once we get fully satisfied on the updates.

The diodes are Fairchild 1N5395 which I had on hand, originally 1N4004.

Will bring over the dummy loads and Sig Gen to (slowly) crank up the 2205, and see if the LIMIT lamps come on, and at the same time measure the voltage across the loads at 400 Hz to get a power reading.


Oops, those aren't the loads.

These ones!



We could do a meter tracking test and plot the results. The data sheet already exists.



How kool would that be?


-Greg