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Worklog: Marantz 2275 Restoration

yeah no worries, i started by cleaning the pcb with a bit of contact cleaner and a ear bud which you dont need to do. But what i used to remove the glue is the citrus based "Desolve-it" and my finger nail. I have acetone, contact cleaners etc but i dont like using any of them on the top of a PCB as it can remove the markings on the board which would be annoying :yes:
 
Great work! I would stay away from the Panasonic SU series bipolars in the signal path - go for poly film or a nichicon ES (not sure if it's been said).

Keep it up! Gonna be awesome!
 
xoaphexox said:
Great work! I would stay away from the Panasonic SU series bipolars in the signal path - go for poly film or a nichicon ES (not sure if it's been said).

Keep it up! Gonna be awesome!
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nope it hasn't been said yet, it was just the recommended one in the list, ive only used 1 so far on the tone board. Anything in particular bad about them? i can always pop in to an electronics store and grab another cap tomorrow :)
 
It's just my personal preference with regards to sound quality. I believe there are better sounding caps out there - I don't mind the sound of Nichicon Muse ES bipolars (made for audio) but I like the Panasonic ECQ-P(Z) polypropylene ones the most. Your mileage may vary - here is an interesting link of someone else's observations regarding the SU series in the signal path: http://www.ecp.cc/cap-notes.html

Although it's still just personal preference and conjecture - my "better" may certainly not be yours. And I doubt just one or two caps will influence the sound very much but there is the whole 'weakest link in the chain' concept.

You are doing a fine job!
 
Well final update for the weekend, spent most of the day on it today between running around grabbing little bits...

I managed to strip it down removing both amp modules, old filter caps and the transformer. I cleaned up the main chassis while the area was clear as best as i could :)

I repainted the transformer as i wasn't happy with the paint on the top of it, refitted it to the chassis and resoldered all the wiring - also installed the new caps with ring terminals and cut down/drilled holes in the main coupling for the 2 caps to suit the new style connectors :)

Overall its been a busy day, the transformer was more of a challenge than i thought it would be, ive never felt something so heavy before :D Trying to heat up big bits of metal with 2 soldering irons always makes for fun and games aswell...





 
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The chassis looks fantastic! The paint job on the transformer looks nice too. Can't wait to see this project done! :lurk:
 
well ive got to that point where im not sure what to do next :scratch2:

both the amp modules are done and the power supply is back in the chassis...

i am yet to do:

P300 - MPX stereo decoding board
P400 - Phono amplifier
PC01 - Dolby FM Level
P150 - AM tuner
P200 - FM IF amplifier
 
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I think you could change all the electrolytics without affecting the alignment.
I like to replace the input coupling caps in the phono preamp ((C401,402) with film types, the board is even made to accept them. Panasonic ECQ-E2105KF fit well.
For all sub 1 uF electrolytic caps and any 1uf electrolytic caps in the audio signal path, I like to use stacked film types. This includes the bi-polars (C306,307,309) and the audio coupling caps (C323,324,325,326) on the MPX board. You can also use stacked film types for the 1uF coupling caps on the Dolby FM board, if you care to.

.22uF/50V stacked film ECQ-V1H224-JL
.47uF/50V stacked film ECQ-V1H474-JL
1uF/50V stacked film ECQ-V1H105JL

Tom
 
catrafter said:
I think you could change all the electrolytics without affecting the alignment.
I like to replace the input coupling caps in the phono preamp ((C401,402) with film types, the board is even made to accept them. Panasonic ECQ-E2105KF fit well.
For all sub 1 uF electrolytic caps and any 1uf electrolytic caps in the audio signal path, I like to use stacked film types. This includes the bi-polars (C306,307,309) and the audio coupling caps (C323,324,325,326) on the MPX board. You can also use stacked film types for the 1uF coupling caps on the Dolby FM board, if you care to.

.22uF/50V stacked film ECQ-V1H224-JL
.47uF/50V stacked film ECQ-V1H474-JL
1uF/50V stacked film ECQ-V1H105JL

Tom
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thanks for that tom :) i brought some stacked films over with the rest of the caps aswell so i should have that covered :) do you find any benifits in replacing the 2 x 1uF caps on the tone board also? though i only ordered 2 anyway lol ;)

Either way i can give it a shot i guess, hopefully it all stays in alignement :)
 
The WIMA box polypropylenes can fit in the footprint of an electrolytic up to about 4.7uF - I use them in the signal path and feel they do a good job. A bit pricey though, at roughly $1/uF
 
Don't forget to adjust bias and DC offset / power supply voltage. Only need a DMM and a screwdriver (hopefully a plastic one)
 
aokman said:
do you find any benifits in replacing the 2 x 1uF caps on the tone board also? though i only ordered 2 anyway lol ;)
Click to expand...

At my age, I'm not sure I can hear a difference, but it makes me feel better to get electrolytics out of the audio path.:D

Tom
 
Sir.Byrd said:
Don't forget to adjust bias and DC offset / power supply voltage. Only need a DMM and a screwdriver (hopefully a plastic one)
Click to expand...

yup none of that should be any problem :thmbsp: it was just the tuner and other adjustments that requires a scope and generator that i dont have the equipment for :scratch2:
 
Well time for an update :D

i have now recapped every board and reassmbled the guts of the amp :)

I have just been through and done the idle current, DC offset and DC supply calibrations.

I ran the amplifier for an hour to warm up the components and let the caps settle in and adjusted to the following results:

DC supply: 35v
Idle current: 9.9mvdc both channels
DC offset: 0.000v both channels





getting a buzz through the speakers at the moment but its probably because the front is dismantled still i guess either that or its grounding as it goes away if i touch the chassis.

The sound it is putting out so far is just astonishing, it has so much more depth than im used to, especially with instruments where you hear the entire action and not just the resulting note.

More to come :D
 
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Very impressive work, how you stripped everything! And very very nice pics of the amps with the white background.

It's incredible clean, I like it very much. Good luck!

Keep on going!

:beerchug:
 
aokman said:
got bored this afternoon and decided to get the annoying bit out of the way which is refinishing the faceplate....

Sanded the scratches out of the face and blended it in with the existing finish - filed and refinished the bezel sides from where the amp has been smacked into things also :)

heres a quick piccie of the results, ill get more detailed ones shortly :)



before:



after:

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AOK, can you describe how you sanded off the scratches on the faceplate without taking off the anodizing? Concerned readers want to know....:yes:
 
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