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2285B just about done 95%

Discussion in 'Marantz Audio' started by Mike Sweeney, Apr 10, 2018.

  1. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    So I'm at the very end with just a few odd things left. I have some wires I need to unwrap and re-wrap/solder because of corrosion. I didn't see the itty bitty board for the main bank of switches with it's four or five caps so I need to pull the tone board out. again.. and do that plus clean up those switches. Thats about it
    Things done
    All new caps on EVERY board :) I've seen "recapped" Marantzs for sale but they skip the AM/FM tuner board. Shame because on the 2285B, the FM tuner rocks it with a good antenna.
    All new power transistors in the power amp module
    New diode arrays in power supply
    New relay
    New LED lighting
    A redo of the two massive dual stage caps to some perfboard mounts with four separate caps
    A replacement of two of the big pots for DC bias/idle current with custom made mounting boards for precision pots. I was able to salvage two of the old pots after desoldering them and giving them a very good scrubbing in DEOxit cleaner and fader lube.
    The four 2SC1345s on the tuner board were replaced with 1845s ( very black legs and noisy)
    Scrubbed, cleaned, rusty transformer was cleaned and repainted, new sticker for the top ( Special thanks to
    wlhd1610 for the decal) etc.
    I painted the inside of the lamp housing white which really helped the overall lighting effect.

    This Marantz sounds really good so far. I'm going to put it to the test with dummy loads and run it up as part of the final check. FM rocks.. AUX works well..


    When this is done, I have the OEM wooden box for it to redo. I'm looking at redoing the veneer with rosewood or the like. Structurally the case is in great shape. It's just chipped to hell

    I call this a rebuilt Marantz, not restored because of some the changes I did without regard to keeping the original look ( like the main filter caps)

    IMG_3446.jpg IMG_3445.jpg IMG_3444.jpg IMG_3422.jpg IMG_3418.jpg IMG_2407.jpg IMG_2400.jpg IMG_2398.jpg IMG_2405.jpg
     

     

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  2. gogofast

    gogofast AK Subscriber Subscriber

    Messages:
    7,988
    Location:
    Seattle
    Great job! Looks like a lot of work. What a difference before and after.
     
    Mike Sweeney likes this.
  3. rBuckner

    rBuckner Luv 2 Restore Subscriber

    Messages:
    9,653
    Location:
    Prescott, Arizona
    A nice restomod to borrow a term from the hotrodders. :biggrin:
     
    Mike Sweeney likes this.
  4. Jailtime

    Jailtime Standin' on a corner Subscriber

    Messages:
    11,406
    Location:
    San Angelo TX
    Nice rebuild, quite the mess before you started on it. I wanna see pictures of the case when you get it done.
     
    Mike Sweeney likes this.
  5. Dingman

    Dingman Do you know where your towel is? Subscriber

    Messages:
    2,467
    Location:
    Des Moines, Ia
    Well done, yup, alot of work there. But man, it's worth it. :)
     
  6. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    Yeah.. I bought this one with the idea of flipping it. For a 2285B with case, I got a good deal on it. But I'm becoming attached to it ;)
     

     

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  7. Fairlane

    Fairlane AK Subscriber Subscriber

    Messages:
    1,770
    Location:
    West San Jose CA
    Just like the rescue puppy. My money is it stays with you.

    Any chance of bottom pictures showing the main filter cap mod if possible, looks very intriguing.
     
    nbarber and Mike Sweeney like this.
  8. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    I'll put some up in a day or so. I'm thinking I might redo the bottom to allow using screw termination of the wires vs the current soldered connections. There is not a thing wrong with the current solder but I think I can improve it a bit. I was mentioning elsewhere that these are the exact same value of what was taken out. It also happens to be the biggest radial caps I could find. Anything bigger has the locking PWB leads and they sit alot closer to the edge of the chassis. The custom PWB I saw done looked like it was spaced up from the chassis but I didnt want to do that. As it stands right now, the perboard is flush on the chassis ( I have some fish paper to put in) and the leads have plenty of room on all sides. I'm using the original ground buss which I want to remake so it's closer to the board. The caps are soldered to the perfboard ( all the eyes have a copper eyelet) which holds them in place then the leads are extended to the ground buss and tied to the + side of the two channels. I have heat shrink over the leads since they are about .5 to .75 inch long extending from the perf board to the buss.
     
  9. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    Here is the bottom of the perfboard adapter on my 2285B. I am going to make a new buss for the ground out of copper. I found a place to get soft copper pretty cheap as remnants and 22 gauge looks pretty close to what I need. I could use thick ( 10 AWG) copper wire also. I'm thinking about both ways.. That will lower everything closer to the board. I think it's less work than using the screw adapters. The way it is right now works. It's just not clean
    IMG_3490.jpg
     
  10. Fairlane

    Fairlane AK Subscriber Subscriber

    Messages:
    1,770
    Location:
    West San Jose CA
    I like it. Plenty of clearance to the bottom panel?
     
    Mike Sweeney likes this.
  11. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    Since it's using the OEM ground buss, there is the same clearance as before. I made my adapter tonight but I'm second guessing myself :D I might just clean up the wiring and let it go.
     

     

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  12. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    A sidebar is that I replaced a D313 power transistor on the power supply board. I had some noise that I could not track down and this being replaced with a TIP 31 cleaned ups the noise. I think the noise stems from the transistor bare metal going to that nasty black tarnish including under the screw tying it to ground. I could have probably cleaned it but I replaced it outright. This also allows new thermal compound under it too. The legs also had the black tarnish but it flaked off ( mostly) when I pulled it. The 1345 transistors had the same black tarnish when I pulled them from the tone board. I don't know how much is normal and how much is from the results of this unit being poorly stored ( see the original images of dirt and filth)



    IMG_3522.jpg
     
    Last edited: Apr 16, 2018
    Fairlane likes this.
  13. 1978_DREAMER

    1978_DREAMER AK Subscriber Subscriber

    I've been following your progress and you've done a very nice job!
    Jerry
     
    Mike Sweeney likes this.
  14. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    Thank you for the kind words. I'm finishing up in a week or two with the electronics. The wooden case is next :) I look at it now and I'm not sure I believe it myself it so nasty when I started.
     
  15. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    So I got the tuner board out and replaced the three caps on the switch board behind it. PIA to get into that spot but as it turns out, both caps were rated at 4.7uf.. but measured over 7uf. One was starting to leak. I got the last transistor replaced on the tuner board and decided to share just how black the leads are oxidizing to. The crap is thick enough to flake off. Needless to say, the tuner board works better now :D The only remaining task is to get some DeOxit into this bank of switches ( mono, tape in, etc) I've got one switch that I thought was broken ( it wouldn't stay in) but when I read up on the multipath switch, it doesn't stay depressed. You press it to check the FM tuning meter to see if you can squeeze a bit more tuning out of it from reflected FM signals.. I need to try this :)

    I'd like to replace the balance pot but it's hard to find a replacement. So I'm going to try some DeOxit Shield on it. There's a guy who does amp restoration I've seen who swears by the stuff for controls that refuse to stop being noisy.

    I had to clean all the knobs.. all of them had a coating of yellow nicotine/tar/?? that I used alcohol and mothers mag polish to clean them up.

    In the pictures below, the first is those last two caps on the switch board. I also did the one floating cap after I took the pic. The next is the oxidized transistors from the tuner board. These are the infamous 1345s. The numbers were from when I was replacing the power amp transistors and I wanted to note the HFE ;) I have a piece of wallboard protecting my table top and so it makes a good scratch pad when it's way too late at night :) The last is the leaking cap.
    IMG_3559.jpg IMG_3562.jpg IMG_3558.jpg
     
  16. catrafter

    catrafter Marantz Specialist Subscriber

    Messages:
    6,212
    Location:
    Montana
    From what I know, one would depress the Multipath button while rotating your directional FM antenna for minimum indication on the Multipath meter.

    Tom
    (from P24 of the owner's manual available on HiFiEngine and elsewhere.)
    MP.jpg
     
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  17. PooPoo

    PooPoo Active Member

    Messages:
    140
    I’m getting some noises and hiss no matter if I turn up the volume the intermittent noise stays the same level. Is this from the D313?
     
  18. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    I had a persistent low level static sound. It sounded like a loose ground wire. I replaced the 331 because it's a known issue on a lot of units and a new TIP is dirt cheap. After seeing the corrosion, I can see why,
     
  19. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    I found a near perfect color match for the "steel" frame on my 2285B and probably more. Tamiya Color (model paint) AS-12 Bare Metal Silver. I had some surface rust all along the front frame. With a dry brush technique, I was able to blend in the new paint with the old and not lose the patina while obscure the rust.

    IMG_3540.jpg IMG_3541.jpg
     
  20. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
    492
    Location:
    Orange CA
    So today I put on the 400 watt 8 ohm loads and let it rip. Full volume, well, 3/4 ish.. right where it started to clip. 15 mins the loads were a bit over 200 degrees.. the final amp transistors were 140 degrees measuring on the case. According to my calcs based on the since wave, I was pushing right about 90 watts a channel. The new replacement transistors seem to work very well. I wouldn't want to bake it like that for a long time but the smoke test went well :D All the replacement caps and diodes etc held up nicely.
     
    Dingman, Steven Tate and wlhd1610 like this.

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