2275 rebuild project

[thxdave]

I don't see 2275 threads here very often so I hope this will help some of the other newbies like me. All credit has to go to Leestereo for his help with this restoration. I never, ever would have attempted such an extensive project if it wasn't for his offer of help. I know enough about electronics repair to be dangerous despite a lifetime of enjoyment of all things audio. I'll try to keep the updates coming on a regular basis to let you know what I've learned along the way. BTW, I'm firmly in the camp of "If it ain't broke, don't fix it" so this puts me WAY outside my comfort zone. However, this AK forum is SO helpful to folks like me that I know you all won't let me get too far off script.

History
I picked up this 2275 from a guy here in Florida a few months ago. It was mostly functional (noisy controls, burnt out dial light, tuner out of alignment, etc.) and came with a fairly nice wood case. The only odd thing was the power cord which was not original. The seller told me that the original cord had been damaged and had been replaced. I didn't notice at the time (didn't even know to look!) that this was an international model. One of my first posts here was about the odd wiring configuration I found coming off of the transformer which was missing the usual jumper wires. I replaced those jumpers, built my own DBT and held my breath....no problems.

Restoration
As I said, Leestereo was kind enough to help build a parts list for this project. Without his help, I might have done the P800 board, relamped to LED, got the tuner aligned and called it a day. But, with a false sense of security, I've plunged into it all the way.

Before I started the resto, I decided to open up the chassis and poke around. I saw that the original dial lamps had partially melted the plastic housing. So, I got a set of blue LEDs as well as a set of warm whites. The blues were TOO blue, so I opted to install the warm whites. As you can see in the first photo, those WW's had way too much green in their output.
(Also note the face feet....thanks to the AK'er who came up with that one!)




Our own dgwojo started stocking a new LED called "Pure White" and I just installed a set. It looks blue in this photo but is a very good neutral white color:


Blue LEDs were WAY too blue for me so these Neutral Whites are perfect.

P800 Power Supply board
This was the first board I worked on as everybody here sees this board as the "heart" of the Marantz. Here's the original configuration and as you can see, this 2275 was amazingly clean and looked like it had very low hours on it except for the caps getting cooked by the resistor:



Here's the P800 after fitting it with the new parts spec'd by Leestereo:



Here's the parts list for P800 with Mouser part numbers in parentheses:
C801 - Original 220uF 63v / Now 470uF 63v (UPW1J471MHD3)
C802 - Original 100uF 50v / Now 220uF 50v (UPW1H221MPD)
C804 - Original 22uF 35v / Now 47uF 50v (UPS1H470MED)
C805 - Original 330uF 50v / Now 680 50v (UPW1H681MHD6)
C806 - Original 470uF 16v / Now 470uF 35v (UPW1V471MPD)
C807 - Original 4.7uF 50v / Now 10uF 50v (UPM1H100MDD)
C808 - Original 47uF 16v / Now 47uF 25v (EKY-250ELL470ME11D)
C809 - Original 220uF 10v / Now 220uF 35v (UPJ1V2211MPD6)
H808 - Original DS131B / Dual Diode (BYQ28E-200,127)
H811 - Original DS131B / Dual Diode (BYQ28E-200,127)
R807 - 150 ohm 5 watt / 150 ohm 7 watt (W221500JRLF)
L801 - MY2Z-02-DC22 relay / Now MY2-020DC24 (MY2-02DC24)

Coming up.....P700 power amp boards

 

[Steven Tate]

Nice work! This will be a fun one to watch. Got a question about the white "legging" on that 150 ohm resistor at R807. Is that ordinary plastic shrink wrap or is it a heat resistant material? There are some resistors similar to that on the 2325 I'm in the planning stages for, and I know heat is an overall problem with that unit. I want to make sure I use the right insulating material when raising those big resistors off the board. Keep the updates coming!
Steve

P.S. I have to put together a set of those face feet. That is an awesome idea.

 

[thxdave]

Hi Steve. I've really enjoyed YOUR rebuilds, too. This is fun for me too but I have to admit I put it off for quite a while until I felt confident enough to get into it.
The white legging came from here
It was not my first choice but I couldn't find the ceramic sleeves like most folks here use. It also appears that it doesn't like contact with extreme heat. I had to reflow that resistor a second time with the soldering iron after the initial installation and the added heat appears to have darkened the material slightly on the bottom of the right leg. If you'd like to try some of it, PM me and I'll mail you a big piece to test. Trust me......I had to buy WAY more of it than I'll ever need! ;-)

The hardest part of this process (so far) has been the dumbest thing imaginable. While I was doing the P800, I kept dropping the trimmed off legs of the new components down into the bowels of the 2275. Thankfully, those little wires are ferrous metal as I was able to reach them with a small magnet but after it happened 3 times, I felt like I had a big KLUTZ sign hanging around my neck! I'm also trying to learn how to do a better "cosmetic" job by making sure that parts are standing up nice and straight when I solder them in. Baby steps....baby steps....

 

[Steven Tate]

I get the baby steps and the flattened forehead syndrome (from slapping my forehead over mistakes - way too often). But we're getting there. I look forward to the rest of your rebuild, and I think I'll take you up on the offer for a little length of that fiberglass insulation. I'll PM you. Thanks!
Steve

 

[rBuckner]

A tip on the cut leads for you. Stick your finger over the lead before snipping, using a free finger on your hand holding the cutters. I also sometimes grab the free lead end with needlenose pliers before snipping them. I have a fetish about knowing where every cut lead end goes and will drop everything if one gets lost. Okay, it's more of an OCD thing!

You may also want to replace that TO-220 transistor on the power supply, the "D331" part as it's had a long hard life! I like the OnSemi MJE15030G here.

 

[Steven Tate]

As a dentist, I have been wondering about one thing since I started this hobby: Orthodontists have a set of wire cutters designed to catch the cut wire end as soon as it is snipped -- don't need wire pieces going down the throat. I wonder if such a design exists for electronics work. I have a pair of those cutters. Their ability to have great access would be limited because the cutting face is 90 degress to the handles -- again, you are cutting off the back end of a wire that goes toward the back of the mouth. But it would be nice when you are cutting off a lead back in a cave if the cutters would grip the cut end.

 

[KutzlerTrans]

Wow them caps were hot. Nice choice. The 2275 is a stout performer and is well constructed.

 

[rBuckner]

As a dentist, I have been wondering about one thing since I started this hobby: Orthodontists have a set of wire cutters designed to catch the cut wire end as soon as it is snipped -- don't need wire pieces going down the throat. I wonder if such a design exists for electronics work. I have a pair of those cutters. Their ability to have great access would be limited because the cutting face is 90 degress to the handles -- again, you are cutting off the back end of a wire that goes toward the back of the mouth. But it would be nice when you are cutting off a lead back in a cave if the cutters would grip the cut end.

Yes, a guest friend is working on his Pioneer in my hobby room weekends as we can and he has such a pair of cutters. They kind of annoy him actually! I'll take a look at them and see if I see a brand name.

 

[Steven Tate]

Yes, a guest friend is working on his Pioneer in my hobby room weekends as we can and he has such a pair of cutters. They kind of annoy him actually! I'll take a look at them and see if I see a brand name.

 

[thxdave]

A tip on the cut leads for you. Stick your finger over the lead before snipping, using a free finger on your hand holding the cutters. I also sometimes grab the free lead end with needlenose pliers before snipping them. I have a fetish about knowing where every cut lead end goes and will drop everything if one gets lost. Okay, it's more of an OCD thing!

You may also want to replace that TO-220 transistor on the power supply, the "D331" part as it's had a long hard life! I like the OnSemi MJE15030G here.

Absolutely agree with you rBuckner. After the first time I let the wire get away from me, I started doing an "inventory" of the wire chunks before proceeding to the next part. I've become a bit anal retentive about keeping a finger or needlenose pliers on the part to be cut. I'm learning bit by bit here. ;-) As to the TO-220, I'll have to check with my "Chief Engineer Leestereo" on this project but I'm open to anything on this project.

 

[thxdave]

Wow them caps were hot. Nice choice. The 2275 is a stout performer and is well constructed.

The caps tested good in spite of being cooked by that resistor. You could NOT keep your finger on that thing when it was running (170F+) and the new one is still running very hot but my IR thermometer has a problem reading the shiny, curved surface so I'm not sure how hot the new one is. However, I'm going to keep it bent away from the new caps as much as possible.

 

[rBuckner]

Yes, a guest friend is working on his Pioneer in my hobby room weekends as we can and he has such a pair of cutters. They kind of annoy him actually! I'll take a look at them and see if I see a brand name.

They are Plato Model 175 "shears" as it says n the handle.

 

[Hipocrates]

Great Work
Kudos!

 

[Steven Tate]

They are Plato Model 175 "shears" as it says n the handle.

Great! I'll do a little research on them.

 

[catrafter]

I have a fetish about knowing where every cut lead end goes and will drop everything if one gets lost. Okay, it's more of an OCD thing!

Randy, while you may have both a fetish and OCD, I am perfectly normal (as far as anyone knows) and do this too.

Tom

 

[rBuckner]

Randy, while you may have both a fetish and OCD, I am perfectly normal (as far as anyone knows) and do this too.

Tom

Ah then, we share the disease of being conscientious.

 

[thxdave]

Sounds like we'll ALL be in therapy by the time I finish this rebuild. I'm trying not to catch scoepage from the fumes! ;-)

 

[thxdave]

Here are a couple shots of the completed P700 board(s). One of the things that I loved about this 2275 is the way the amp boards lift out. Sure makes it easy to work on! How many other models are built this way? First is a closeup shot of the one of the diodes fitted with the fiberglass "legs" with C702 (green) and some yellow shrinkwrap holding two KSC1845's together. One other question: should I hit those 1845's with a heatgun to pull them tight together or just let the normal heat do it for me?



Here's the overall shot of the finished board:



Here's the original shot of the board pre-rebuild:



And here's the parts list via Leestereo's recommendations with Mouser part # in parentheses:

C701 - Originally 1uF 100v / Now 1uF 450v (ECW-FD2W105J)
C702 - Originally 47uF 16v / Now 100uF 25v (UES1E101MPM)
C703 - Originally 10uF 16v / Now 47uF 50v (UPS1H470MED)
C704 - Originally 10uF 16v / Now 47uF 50v (same as above)
C707 - Originally 220pF / Now 220pF 100v (RCE5C2A221J0K1H03B)
C708 - Originally 5pF / Now 5pF 100v (RCE5C2A5R0C0K1H03B)
H701 - Originally 2SC1327 / Now KSC1845 (KSC1845FTA)
H702 - Originally 2SC1327 / Now KSC1845 (same as above)
H703 - Originally 2SA721 / Now KSA992 (KSA992FBTA)
H715 - Originally WZ-150 / Now (BZX85B15-TR)
H716 - same as H715

 

[wlhd1610]

Yes ,put a tiny dab of heatsink compound between before hitting them with the heat gun.

Bob

 

[thxdave]

Rats, I don't have any compound. Can I use the stuff that you'd use on CPU heatsinks?