Wrecked and blown up 4400 - Resurrection

Discussion in 'Marantz Audio' started by Jailtime, Nov 15, 2017.

  1. Jailtime

    Jailtime Standin' on a corner Subscriber

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    Been making some nice progress last few days, rebuilt all the tone, preamp, and filter boards. It took some creativity to fit WIMA film caps on the PD01 tone board, don't think I'd recommend trying that. Managed to break a few solder pads on the PD01 board, thanks to Marantz's piss poor design that puts all the stress on those little pads. I replaced all the transistors on PD01 as well, I really don't want to separate it again. KSC1845 and KSA992 will cover those.

    There's 4 of those little VD1212 varistors on the PE00 preamp board, they're marked as RE21, 22, 23, and 24 on the board. That's clearly not right, another error on a Marantz circuit board.

    Also installed some nice Mallory filters, they're 4.125" tall and just fit. Nice to have that bit of extra space, gives you some more options for filters. I put 3.3uF bypass caps on the filters. While I was working on the filters, one of the socket tabs for those goofy diodes (?) mounted on the heatsink just crumbled. I hard wired directly to the diode leg to fix that. Something to be aware of when you're digging in there, those things are delicate.

    I got my scope tube reinstalled as well, seems I only have a vertical line from center when "audio" button is engaged. I'm guessing those FETs on the driver board are the culprit. I'm just happy that the scope has a trace at all right now.

    I have a weak rear right channel in 4x50 mode also, it was that way on my baseline test, was hoping it would just fix itself during the resto. It's basically whisper quiet. I suppose the problem could still lie in the amp boards that I haven't rebuilt yet.
     

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  2. Jailtime

    Jailtime Standin' on a corner Subscriber

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    Well, I figured out why I didn't have a right rear channel. Did some sleuthing with the o-scope, found I had good signal through the preamp and tone sections. Looked for signal at the power amp inputs, one of them was missing. That narrowed it down to only two boards, the filter amp and the switch board. No signal on JH04, one of the inputs to the filter amp, so the filter amp is good. Let's keep looking, follow JH04's wire back to the switch board, oh that's not supposed to be hanging free. :no: It must have been pinched off in the shipping accident. This is the hi/low filter and speaker switch board, totally buried. Off with the front chassis again.
     
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  3. jstang

    jstang Honey,I can't hear you... Subscriber

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    I use my 4400s for a 4 channel surround system for home theater ... with a Marantz DP870 to decode the source. Configured the DP for 4 channel.

    Was watching "Guardians of the Galaxy" with an audiophile friend over the over the house.... THE 4400 KNOCKED HIM OVER..... AND ALMOST KNOCKED OVER MY HOUSE.... :)

    johnk
     
  4. Rasputin47

    Rasputin47 Woad

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    Another great restoration thread, I'm enjoying following it and look forward to picking up all of the tips I can!
     
  5. Jailtime

    Jailtime Standin' on a corner Subscriber

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    Thanks, that's why I'm posting some of my findings during this restoration. If we get enough threads out there, you can piece together the info you need to troubleshoot a 4400.
     
  6. Makis

    Makis New Member

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    45
    I just gave mine yesterday for a restoration,even though it was mostly working fine. If I have any info from the repair guy (something that other restorers should pay attention to), I will let you guys know.
     

     

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  7. Jailtime

    Jailtime Standin' on a corner Subscriber

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    Got all 4 channels back again, it's not all that hard to get to the component side of the switch board PS01. I pulled the power switch, volume pot, and tone board; that gave me enough room to solder the offending wire back to the low filter switch. Now if you want to get to the foil side of PS01, that's a whole different story. Front chassis has to come off for that job.

    Riddle me this, my scope works great displaying FM and AM audio, has that nice "X" pattern that fills the whole display. AUX mode has a weak little pattern that only uses about 25% of the display (this is all in vari-matrix mode).
     
  8. catrafter

    catrafter Marantz Specialist Subscriber

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    It's a lot of work to change those four little blue/gray electrolytic capacitors on that board.

    Tom

    JP4400 Filt loud (2).jpg
     
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  9. Jailtime

    Jailtime Standin' on a corner Subscriber

    Messages:
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    Here's a shot of the aftermath. Replaced -

    1 wrecked faceplate
    1 melted lamp housing (looks like a small campfire was built in there)
    18 lamps
    33 transistors
    10 varistors
    2 main filter caps
    148 electrolytic and tantalum capacitors

    That's the best count I can get, I think a few parts found their way into the trash instead of into my neat little piles.

    IMG_7734.JPG
     
  10. jstang

    jstang Honey,I can't hear you... Subscriber

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    My oh my.....

    I did two full recaps of 4400....the things are buried every imaginable place. Each recap took a week for my eyes to get back to normal.....o_O

    jk
     
  11. Jailtime

    Jailtime Standin' on a corner Subscriber

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    Well, here it is all finished up. Power supply, bias, and DC offset all dialed in. Tuning sections work great. Got the scope tweaked just right. I'm really happy with how it turned out, think this one will be a keeper.


    IMG_7710.JPG IMG_7712.JPG IMG_7739.JPG IMG_7743.JPG
     
    Last edited: Jan 25, 2018
    spinroch, onepixel, Bdbras84 and 2 others like this.

     

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  12. tonebells

    tonebells AK Subscriber Subscriber

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    Well done!
    Tony
     
  13. Steven Tate

    Steven Tate AK Subscriber Subscriber

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    Beautiful! :thumbsup:
     
  14. catrafter

    catrafter Marantz Specialist Subscriber

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    That's a beauty, Kyle.
    You did a great job!

    Tom
     
  15. rBuckner

    rBuckner Luv 2 Restore Subscriber

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  16. SoCal Sam

    SoCal Sam Lunatic Member

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    Wow! Simply stunning!!
     

     

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  17. jstang

    jstang Honey,I can't hear you... Subscriber

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    Sure is pretty.... Is some one still making the light baffles?

    And why do I a feel like I am being chased by a pod of dolphins....?

    jk
     
  18. Jailtime

    Jailtime Standin' on a corner Subscriber

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    Yeah there's a seller on Ebay who makes really nice 3D printed ones. He engineered all the weak points out of it, like the open tabs that the screws always crush. Much thicker, and fits really well.
     
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  19. jstang

    jstang Honey,I can't hear you... Subscriber

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    Are you seeing dolphins? Or am I hung over....?


     
  20. Bdbras84

    Bdbras84 AK Subscriber Subscriber

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    Location:
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    Wow!! That is a stunning piece!!!!! Guys like you are truly inspiring guys like me to want to keep learning how to fix these gems back up. Thank you for posting this thread, you're progress and explanation of what you were doing. It really helps guys that like me to understand this hobby alittle bit more at a time.
     

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