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MR80

68.7.9.132
Posted on December 15, 2019 at 17:02:21
Cougar
Audiophile

Posts: 4593
Location: SoCal
Joined: June 25, 2001













I finally got around to finishing up Power Supply PCB 1 & 2. These pics are the NEW caps and resistors I put in since the person who did the last "Upgrade" didn't do such a good job after I started to look more closely. The guy put Panasonic NHG caps (most of them) and they had a 2D dead sound to them.

I found caps (Radial) where axial should go but that wasn't the issue, there was bare wire showing from the wire of the extension going to the solder side on the PSU 1 pcb. Then I also found caps that the voltage ratings were way too high. I understand for the rectifiers but really not needed for the outputs of the voltage regulators. I also found a bad trace that when the person did the upgrade he messed up an Island pad that was barely making contact. So I repaired that too. So I put everything back to what Mac had in the parts list.

I replaced all the caps with Vishay BC Component Axial lead caps, Kemet Cap, Elna Cerafines, Audio Note Kaisei, Nichicon UFA, Elna RBD Bipolar, Elna Simics, and Takman resistors in the signal path.

Everything sounds really nice but I know it will need along break-in time before final judgement.

Next up will be upgrading the pcb where all the audio signal comes from. Then I should be done with the audio portion of the upgrades.

One thing I did notice is that the stations don't drift (just a little bit) like before I changed out the caps. So that was a good surprise.

Here are some pics of what I did.

 

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Here what was in there before., posted on December 15, 2019 at 17:37:21
Cougar
Audiophile

Posts: 4593
Location: SoCal
Joined: June 25, 2001






This was what the other person did before I changed it.

 

RE: MR80, posted on December 15, 2019 at 19:22:15
kingjim1954
Audiophile

Posts: 49
Location: usa
Joined: March 29, 2009
 Nice, Cougar! I have an MR-78 that was upgraded by Modeferri about 24 years ago. I was in upstate New York and my favorite classical station was a couple hundred miles to the north. Today I am north of Boston. My go to tuner is a Scott 310E (modded by me). I totally agree with Timbo and have an APS-13 on my roof with rotor, to drive it. It sounds wonderful! Fortunately both of my favorite stations are in close enough line to not have to fiddle with the antenna when switching. The only negative is New England's strongest station is directly in my backlobe. no sweat for the APS. I need to try out the Mac again.It had the absolutely best noise background, as black as night.

 

well done, maate!, posted on December 15, 2019 at 22:55:38
Timbo in Oz
Audiophile

Posts: 23221
Location: Canberra - in the ACT - SE Australia
Joined: January 30, 2002
 PSU's matter!

everything matters.


Warmest

Tim Bailey

Skeptical Measurer & Audio Scrounger


 

Thanks!, posted on December 16, 2019 at 22:25:30
Cougar
Audiophile

Posts: 4593
Location: SoCal
Joined: June 25, 2001
 I have a Fisher KM60 that is my go to tuner as well, but this McIntosh MR80 is sounding pretty darn good so far and has closed the bap between it and the Fisher!

 

RE: well done, maate!, posted on December 16, 2019 at 22:30:10
Cougar
Audiophile

Posts: 4593
Location: SoCal
Joined: June 25, 2001
 Thanks Timbo. Yes, the power supply is very important and is always the first thing I do in any upgrade. As of today with 58 hours on the upgrades, my Mac MR80 is sounding really nice and has really closed the gap between it and the Fisher KM60 I have for best sound quality. I will be going on to the Multiplex PCB where the Audio is coming from to do the next stage of the upgrades.

 

Wow......, posted on December 21, 2019 at 09:48:37
Cougar
Audiophile

Posts: 4593
Location: SoCal
Joined: June 25, 2001
 Now that I have around 150 hours on the upgrades, this MR80 is sounding just awesome! It is very musical now and it sounds more "Real" than before. What I mean is now I can play some music and the strings and cymbals are clear but I can hear the guitar players actual tone to his guitar being a little dirty sounding that separates it from the other music being played. Or vocals being different than the rest of the music and not all sounding the same as being all clear and same tone, if that makes any sense. Sorry if it ain't making sense, I'm trying my best to explain what I'm hearing.

Overall, I'm very happy and surprised the way this upgrade came out and now I have a super tuner that matches my Fisher KM60 in sound but with the ability to pulling distant stations.

 

Nice work, posted on January 1, 2020 at 06:21:35
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 As Timbo said, power supplies matter, and you've done a good job with yours.

I've got a few tuner power supplies which need similar attention, so thank you for the inspiration. It's good to read that you're liking the improvement!

 

RE: Nice work, posted on January 2, 2020 at 18:57:20
Cougar
Audiophile

Posts: 4593
Location: SoCal
Joined: June 25, 2001
 1973shovel, Happy New Year!

Yeah today I continued the repair and replacement of more things wrong. So I'm just fixing what this guy did like put a 100uF 100Vdc Nichicon Fine Gold cap where a 100uF 16Vdc cap should be. Then he put 2.2uF caps where 3.3uF caps should have been in the signal path. I also found one of the wires that go to where the 75ohm antenna circuit is at was ready to come off, so I had to fix that too. I put Elna RBD, Silmics II, and Cerafines in there. Now letting it break in again. The Super Narrow function works a lot better than before which it seemed like it wasn't working. I know the alignment will fix this stuff.

I will try to post some pics. I have one last PCB to work on before I send it to get aligned.

 

When you get it back from alignment..., posted on January 3, 2020 at 06:27:29
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 ...please let us know who did it and if you're happy with their work. I have a MR-78 I've considered having touched up.

Regarding the 2.2 uF vs the 3.3 uF caps, did you consult more than one source for that information? I'm asking, because sometimes in process production changes occurred (not specifically at McIntosh), and what the unit was made with conflicts with the schematic. He may have replaced the 2.2 uF simply because that was what was in there, although he may have been sloppy and thought "close enough". As an example, one of my Dynaco tube amps has a 1 uF cap in the feedback loop, but the Dynaco parts list calls for a 0.1 uF cap. Dave Gillespie confirmed for me that the 1 uF value is correct, and the 0.1 uF was a Dynaco typo error.

It's good to hear that your work is paying off with better performance. Thanks for the posts!

 

RE: When you get it back from alignment..., posted on January 3, 2020 at 08:10:30
Cougar
Audiophile

Posts: 4593
Location: SoCal
Joined: June 25, 2001
 It was also in the McIntosh parts list in the service manual I got from McIntosh. I will send them a email confirming just to safe.

I really don't trust anything that person did in this MR80, it looks like he just used what ever he had to get through the recapping. He even forced leads of caps that didn't fit into the island pads and bent leads all crazy like due to part being to big to fit just to make them fit. That's how I found that one trace damage was due to that.

I have read many post on different forums that the MR78 very close to the MR80 for pulling stations. I don't know how it sounds personally but I have read good things. I still have my FM-3 upgraded and the Fisher KM60 that just so nice sound. The KM60 is still the best sounding tuner I have but the MR80 is getting closer! :)

Have you done any more upgrades to your FM-3?

 

It sounds like the nut behind his soldering iron may have been loose, posted on January 3, 2020 at 13:00:13
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 From the sound of things, it doesn't sound like he did quality work.

I'm glad the MR-80 is in good hands now!

 

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