Restore a Marantz 2275 for me

[freax]

Hi, I am welcome to some helpful advice on where I could get components for such an old beast.

I'm considering restoring a pretty good condition Marantz 2275, I've heard it play and it sounds just fine, except for every now and again it generates some crackling, no doubt one of the many components which have reached and exceeded their useful life expectancy...

So I've decided to start a list of components to purchase, first off is capacitors, But I've already hit a snag, the two main filtering capacitors, both rated at 13,000uF at 55 volts with package dimensions of 51mm W x 70mm H.

They don't exactly have a modern counterpart, closest i can find is a 15,000 uF, so its clearly different to what I've got available today.

My first question in regards to the replacement capacitor is, is it a close enough drop-in component or will the rectifier be overly stressed enough to warrant upgrading? a Toshiba 6C3.

Also will voltage drop significantly or is there no trouble in this reguards?

In addition to that, is there anything else I should be concerned about, I'm not exactly an electronics expert, I'm just starting out infact, this is my first real restoration project..

The main goal of this restoration project is to bring it up to at-least working condition and maybe towards modern specifications, without too much loss in the original tonal quality, however no doubt a lot of the resistors will be in terrible condition, swaying out of value, so that will be the next step..

By the way, a schematic/service manual scan would be greatly appreciated.

Thanks in advance.

 

[freax]

just resoldered the LHS amp board, going to try it out to see if it (the output transistors) still work.

When I pulled it out of storage the left hand channel was completely gone.

EDIT: Eureka!, I now have audio from the left channel, however it is distorted when the volume control is turned up and it is at a very low level, nothing like the right hand channel which is loud and undistorted.

 

[TANDBERGEREN]

The filter caps have typically a tolerance of -20% to +50%

This means that a capacitor labelled 13000uF may have an actual value between 10000uF and 20000uF.

So feel free to put in any cap you can find place for within lets say 63V rating.
(55V caps are rare) If a 30000uF (therytically) Cap fits mecanically, Its just fine.
Give You some more powerreserve in the bass region.

Please appology my poor English, I'm just a Norwegian

 

[DUG]

This might help:
http://akdatabase.org/AKview/albums/Marantz/Marantz 2275 Service Manual.pdf

http://akdatabase.org/AKview/albums/Marantz/Marantz 2275 US schematic.PDF

 

[freax]

Thanks for the help gents, after some google searching I have discovered these links:
Electrolytic Capacitor Shoot-Out - AudioKarma.org Home Audio Stereo Discussion Forums

Marantz 2275 Restoration - 1974 - Overclockers Australia Forums

I have a Ortofon Super OM 10 Stylus on its way to go with my Technics SL-1300 that I've just recently fixed by resoldering every soldered contact inside and a MJ vinyl arriving soon too.

Would be nice if someone could release a bias psu kit to go with my Matsushita EPC-451c (Got it for free out of a discarded turntable) cartridge too but alas I'll have to wait until I can build one myself from scratch.

Which has sparked off the need for a vinyl preamp or an amplifier which can support a turntable...

Hmm this looks interesting: http://forums.overclockers.com.au/showpost.php?p=11111909&postcount=33

Panasonic THA series 15,000uF 80v caps

I might put an order in for some more capacitors aswell.

 

[freax]

http://i.imgur.com/ucB7C.jpg
http://i.imgur.com/3UKKe.jpg

A bit rusty atop of that transformer, will have to wait.

 

[freax]

Just incase oc.com.au change their forum site/software whathaveyou I've copied the parts list from there to here:
# Quantity P.no.
1 2 P10247-ND CAP 470UF 16V ELECT FC RADIAL 0 0.47000 $0.94
2 2 P11258-ND CAP 330UF 50V ELECT FC RADIAL 0 1.30000 $2.60
3 2 P10347-ND CAP 220UF 63V ELECT FC RADIAL 0 0.90000 $1.80
4 2 P11183-ND CAP 220UF 10V ELECT FC RADIAL 0 0.39000 $0.78
5 2 P10323-ND CAP 100UF 50V ELECT FC RADIAL 0 0.44000 $0.88
6 6 P11196-ND CAP 47UF 16V ELECT FC RADIAL 0 0.34000 $2.04
7 2 P11230-ND CAP 22UF 35V ELECT FC RADIAL 0 0.34000 $0.68
8 12 P11250-ND CAP 10UF 50V ELECT FC RADIAL 0 0.18800 $2.26
9 2 P13197-ND CAP 15000UF 80V ELECT THA 0 23.93000 $47.86
10 1 Z2633-ND RELAY PWR DPDT 5A 24VDC 0 7.26000 $7.26
11 22 P11212-ND CAP 10UF 25V ELECT FC RADIAL 0 0.12500 $2.75
12 2 PF2105-ND CAP 1.0UF 250V METAL POLYPRO 0 0.79000 $1.58
13 26 P10312-ND CAP 1UF 50V ELECT FC RADIAL 0 0.13700 $3.56
14 2 P10294-ND CAP 100UF 35V ELECT FC RADIAL 0 0.38000 $0.76
15 2 P10271-ND CAP 220UF 25V ELECT FC RADIAL 0 0.38000 $0.76
16 2 P11199-ND CAP 220UF 16V ELECT FC RADIAL 0 0.48000 $0.96
17 4 P10290-ND CAP 33UF 35V ELECT FC RADIAL 0 0.34000 $1.36
18 12 P11213-ND CAP 22UF 25V ELECT FC RADIAL 0 0.13700 $1.64
19 16 P10315-ND CAP 4.7UF 50V ELECT FC RADIAL 0 0.13700 $2.19
20 12 P10269-ND CAP 100UF 25V ELECT FC RADIAL 0 0.15300 $1.84
21 2 P11181-ND CAP 100UF 10V ELECT FC RADIAL 0 0.34000 $0.68
22 10 P4540-ND CAP .22UF 63V STACK METAL FILM 0 0.13300 $1.33
23 10 P4671-ND CAP .47UF 50V STACK METAL FILM 0 0.18200 $1.82
24 4 P5560-ND CAP .22UF 50V ELECT NHG RADIAL 0 0.24000 $0.96
25 2 P10296-ND CAP 220UF 35V ELECT FC RADIAL 0 0.48000 $0.96
26 2 P10776-ND CAP 100UF 100V ELECT FC RADIAL 0 1.01000 $2.02
27 10 P10314-ND CAP 3.3UF 50V ELECT FC RADIAL 0 0.13700 $1.37
28 10 P1175-ND CAP ELECT 4.7UF 25V SU BI-POLAR 0 0.15300 $1.53
29 2 P1195-ND CAP ELECT .47UF 50V SU BI-POLAR 0 0.24000 $0.48
30 5 478-1890-ND CAP TANTALUM 3.3UF 35V 10% RAD 0 0.65000 $3.25
31 5 478-1834-ND CAP TANTALUM 1UF 25V 10% RAD 0 0.46000 $2.30

NOTE: These are digikey.com parts numbers and you will need to use the .au digikey site (http://www.digikey.com.au/?curr=AUD) if you are ordering from AU, and pay $34 for shipping, so might aswell save up about $180 and buy them all at once.

ty, aokman for the hard work!

 

[DUG]

"A bit rusty atop of that transformer, will have to wait."

soft cloth and some oil

 

[Coconuts 500]

Do not buy 0.47uF bipolar electrolytics. Instead replace with the cheapest 470nF polyester caps you can find.

Your weak channel sounds like a loose wire somewhere. Happens a lot when working in these old pieces.

 

[freax]

Do not buy 0.47uF bipolar electrolytics. Instead replace with the cheapest 470nF polyester caps you can find.

Your weak channel sounds like a loose wire somewhere. Happens a lot when working in these old pieces.

roger, thanks for that, I'm redoing all of the solder joints on the tone board today... waiting for my deoxit to arrive.

 

[freax]

holy moly!
i just fixed my marantz 2275
fully
i now get audio from both speakers

The problem turned out to be a dry joint on the tone board

*dances to some FM Stereo music*

I'm back in business baby!

 

[freax]

Well after a few hours of listening the Left channel decided to go out again, but at least this time I am able to coax it back on by turning up the volume, which is more than I can say about what it was doing before.

I won't push it any further and just let it rest until I can afford the necessary capacitors.

Any suggestions as to what could be causing this would be greatly appreciated but I am just going to put it down to bad op amps in the tone board or bad capacitors...

 

[freax]

Think I'll hold off on the deoxit on pots for this amp, been reading about how it can remove all of the oil/grease from the shaft and remove the smooth feeling from the pot, my volume pot on this one is pretty rough, I might have to add some kind of oil to its shaft.

Anyway, time for bed.

 

[Coconuts 500]

Definitely clean the pots and switches. The smoothness may go away to some extent, but it always comes back eventually (can take months). It is not worth it to keep an amplifier unreliable just because you need the knobs to be smooth.

Your channel cutting out may very, very well be dirty pots or switches, but it definitely sounds like a bad relay, since the sound came back when you increased the volume.

Clean the relay by taking off the plastic cover (some force may be necessary), and rubbing the contacts inside with some alcohol soaked paper. See if that solves your issue. That is a short term fix. A real fix is a new relay.

 

[sssmokin99]

The transistors on the power amp boards are notorious for becoming leaky after this many years. Usually it starts out with the sound in one channel becoming distorted, maybe intermittantly, then all the time. You need to replace the electrolytics on the amp board if you have not already done so, the protection relay, etc., and then the transistors (the pairs) in that channels board. The outputs usually are not the problem. I have three 2275's and one of them did this a couple of years ago.

If it is just the relay, be aware of the transistor issue....

You can isolate it to the specific amp board just by switching them, since they plug-in. If the trouble follows, you know where it is....

 

[freax]

Definitely clean the pots and switches. The smoothness may go away to some extent, but it always comes back eventually (can take months). It is not worth it to keep an amplifier unreliable just because you need the knobs to be smooth.

Your channel cutting out may very, very well be dirty pots or switches, but it definitely sounds like a bad relay, since the sound came back when you increased the volume.

Clean the relay by taking off the plastic cover (some force may be necessary), and rubbing the contacts inside with some alcohol soaked paper. See if that solves your issue. That is a short term fix. A real fix is a new relay.

Yes I will desolder the relay today and clean it thoroughly and while I'm there I'll resolder that board. Thanks for the reminder.

 

[freax]

The transistors on the power amp boards are notorious for becoming leaky after this many years. Usually it starts out with the sound in one channel becoming distorted, maybe intermittantly, then all the time. You need to replace the electrolytics on the amp board if you have not already done so, the protection relay, etc., and then the transistors (the pairs) in that channels board. The outputs usually are not the problem. I have three 2275's and one of them did this a couple of years ago.

I didn't notice ANY distortion yesterday while listening and it was at high volume levels with my Technics spinning The Police and then I shut the amp down and hooked up my Marantz CD-65 and spun KMFDM - Nihil, it was then (Using AUX) that the left channel just crackled and went out, then was coaxed back in by the volume control, I rinsed and repeated that a couple of times based upon my daringness, haha.

But I don't think its AUX related, because the amp was working perfect with Radio/Phono sources before I turned it off inorder to switch from Vinyl to CD.

All I heard was loud, boomy, clear, transparent audio, up until that point. Which was very welcoming compared to the sterile sound that is generated by my Sony STR-K670P., Which I'm thankful to say I didn't buy brand new but was a cheap 2nd hand pickup.

You can isolate it to the specific amp board just by switching them, since they plug-in. If the trouble follows, you know where it is....

Step two will be doing that if the relay board resoldering/cleaning doesn't fix the issue. Thanks for the tip!

 

[freax]

Well thats that done, now to clean it and start resoldering..

I figured this was the safest way because simply pulling the top off isn't that simple, I would've probably cracked the PCB before I got that top off..

Hard to believe that these contacts could be dirty, they look brand new to me:

Ah, spoke too soon, they do have deposits on them. Wheres my q-tips.

Well THERES your problem! lol....

Clean enough, maybe...:

 

[freax]

All done, resoldered the entire board and cleaned the relay, and replaced C806 (I have 470uF 25v caps on hand, Nichicon FW(M))

Now to try it out...

So far so good, both channels are restored.

The TDA1541 is certianly quite deep and well detailed with bass + vocals isn't it, very nice. And the Marantz complements that with a powerful punch to the guts.

 

[lanchile]

All done, resoldered the entire board and cleaned the relay, and replaced C806 (I have 470uF 25v caps on hand, Nichicon FW(M))

Now to try it out...

So far so good, both channels are restored.

The TDA1541 is certianly quite deep and well detailed with bass + vocals isn't it, very nice. And the Marantz complements that with a powerful punch to the guts.

a few points to name! all switches, balance controls, potentiometer, should be clean with tuner/contact cleaner and always after spraying them start moving and pushing switches/balances "many times" at least 20 times to make sure they are lubricated and cleaned properly, the relays should be clean with very fine metal sand paper that way the contacts are real clean and shiny and make good contacts. Those Marantz are very good units for sure, but look for dry-out caps and change them also bad connections. make sure you have the schematic and adjust bias and dc-offset.