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Thread: I got a new amp today.

  1. #21
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

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    Last edited by 80's_Metal; 03-31-2019 at 02:09 PM.

  2. #22
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    I stumbled upon this thread in my searching


    https://music-electronics-forum.com/...ead.php?t=5143

  3. #23
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    It looks to me like those screws holding those onto the heat sinks have been out a time or two before?

    And the heat grease is in 2 different colors too. Ha ha

  4. #24
    Braindeadologist GoldenVulture's Avatar
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    Default Re: I got a new amp today.

    Quote Originally Posted by 80's_Metal View Post
    It looks to me like those screws holding those onto the heat sinks have been out a time or two before?

    And the heat grease is in 2 different colors too. Ha ha
    Yes and they've heaped on way more grease than they need. It really only needs to be a thin layer between the back of the chip and the heat sink.


    Also that chip is a replacement / equivalent type. That's what NTE make. They're usuall a bit more expensive too.
    According to one of the threads I found it is a TDA7293V.
    Last edited by GoldenVulture; 03-31-2019 at 02:34 PM.

  5. #25
    Braindeadologist GoldenVulture's Avatar
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    Default Re: I got a new amp today.

    Quote Originally Posted by 80's_Metal View Post
    I stumbled upon this thread in my searching


    https://music-electronics-forum.com/...ead.php?t=5143
    That's one of the threads I found . It's got the correct chip type listed in it.

  6. #26
    of the Forum PFDarkside's Avatar
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    Default Re: I got a new amp today.

    The previous owner probably had them go up in smoke and replaced them once before. Good luck!
    Oh no.....


    Oh Yeah!

  7. #27
    Braindeadologist GoldenVulture's Avatar
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    Default Re: I got a new amp today.

    Here's the other thread I found. It has a few partial bits of the circuit linked. Posts #25 & #26

    - https://music-electronics-forum.com/...ead.php?t=3873 -
    If you could see what those ceramic resistors are on the circuit board and their part number on the board that would help.

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    Last edited by GoldenVulture; 03-31-2019 at 02:57 PM.

  8. #28
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    Quote Originally Posted by GoldenVulture View Post
    If you could see what those ceramic resistors are on the circuit board and their part number on the board that would help.
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    These help? Or what am I looking for.

  9. #29
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    Too bad I can't just order 4 whole boards and just screw em on and plug em in. Ten minute job. No soldering.

  10. #30
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    Dear Marshall Amplification, I need 4 of these stat:
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    And a couple fuses too

  11. #31
    Braindeadologist GoldenVulture's Avatar
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    Default Re: I got a new amp today.

    Sorry I wasn't clearer about that. Those BIG ceramic resistors on the board underneath the Module board that I circled in the pink. If you identify them for me I may give some advice regarding them and the module boards. They may be something that other people are overlooking when trying to repair these amps.

    You may be able to actually order those boards but it's probably price prohibitive. Also for the above possibility , drop in and replace might not quite work.





    These are actually 10 Nanofarad capacitors.
    Last edited by GoldenVulture; 03-31-2019 at 07:34 PM.

  12. #32
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    Sorry I missed the pink ha ha.
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  13. #33
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    So here's what specifically happened when it blew.

    I had decided to try my e1 legendary amps in the effects loop.
    As I was working with the levels and whatnot on the amp 1 clean channel, I reached around the back and there's a switch/button to add db or -db in the effects loop.
    I pushed that button in and snap! I saw the spark from the fuse go, and smelled a burning smell.

    Went to hardware store replaced the fuse, (amp apart now on the bench) and plugged it back in and tried to power it on.... Bzzz fuse snapped again and smoke from the two ic units I am pointing to in pix.

    Don't know if that tells you anything but that's what happened.

  14. #34
    Braindeadologist GoldenVulture's Avatar
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    Default Re: I got a new amp today.

    Quote Originally Posted by 80's_Metal View Post
    Sorry I missed the pink ha ha.
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    Thanks but there's another two I think to the left under the output module board. I need to know what they are. That screw in the middle of the chip holds the modules in . Undo that if you can and lift up the module. you could even unplug it too.

    Chances are they are also .1 Ohm resistors which sit on the outputs of the modules. If they're not replaced it will most likely blow again. They're linked to the protection circuitry as well as the output modules.
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ID:	97082 I don't know if you can read this but if you look at output 1 and output 2 , there are 3 resistors connected to them labelled OR1, that's the ceramic resistors. [ OR1 = .1 Ohms ]

    Available modules from England.
    - https://www.proaudioservice.co.uk/pr...odule-tda7293/ -
    Last edited by GoldenVulture; 04-01-2019 at 02:40 PM.

  15. #35
    Braindeadologist GoldenVulture's Avatar
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    Default Re: I got a new amp today.

    Quote Originally Posted by 80's_Metal View Post
    So here's what specifically happened when it blew.

    I had decided to try my e1 legendary amps in the effects loop.
    As I was working with the levels and whatnot on the amp 1 clean channel, I reached around the back and there's a switch/button to add db or -db in the effects loop.
    I pushed that button in and snap! I saw the spark from the fuse go, and smelled a burning smell.

    Went to hardware store replaced the fuse, (amp apart now on the bench) and plugged it back in and tried to power it on.... Bzzz fuse snapped again and smoke from the two ic units I am pointing to in pix.

    Don't know if that tells you anything but that's what happened.
    It appears they're really touchy when swapping things around and respond like I described further back. I'm guessing the guy that sold it to you did a fix but missed a few things. It looks like if you change much around while it's on or off, and there's power in the caps [ even after it's been turned off ] , they want to blow up.

    It appears if you have it on [ in working state ] , turn it off and change speakers without the power draining right out first , they'll blow up. Also very easy to short the outputs.
    Last edited by GoldenVulture; 03-31-2019 at 11:27 PM.

  16. #36
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    Yes, from what I've been reading, you can't change anything with power on or kaboom. Which makes the amp worthless in a recording situation ha ha. Or a testing new stuff out situation....

    The resistor on the other end was identical to the one pictured, so I assumed the middle one was too.
    I can look when I get home tonight
    Last edited by 80's_Metal; 04-01-2019 at 06:58 AM.

  17. #37
    Braindeadologist GoldenVulture's Avatar
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    Default Re: I got a new amp today.

    Quote Originally Posted by 80's_Metal View Post
    Yes, from what I've been reading, you can't change anything with power on or kaboom. Which makes the amp worthless in a recording situation ha ha. Or a testing new stuff out situation....

    The resistor on the other end was identical to the one pictured, so I assumed the middle one was too.
    I can look when I get home tonight


    May as well presume it is the same, most likely. They're probably damaged from from previous blowups
    Anyway those three need to be replaced too if you do a module fix and they're pretty critical when it comes to correct operation.

  18. #38
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    GV you are the man!

  19. #39
    Underglazed Hair Metalologist 80's_Metal's Avatar
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    Default Re: I got a new amp today.

    So many questions and options here:

    The website that has the modules only has 3 in stock.... F.
    I Can't seem to dig any more up from any source. $136 for 4 modules.

    OR I could just buy the chips, they're like 11 bucks each and either solder them in myself... (Risky)
    Or take the modules to my local music shop guy and pay him to do it. Cheap!

    Then if I get it running.... Do I keep it and never trust it and always be concerned about it?
    OR sell it off?

    I suppose knowing what I now know about these amps, I could just be very careful with it's operation.....

    I could sell it off for $200 as a broken amp and still be good with that, the way that whole deal went down...

    I do enjoy a challenge and learning more about amps and how they work.

    My old Peavey sounded pretty good the other night ha ha ha less headaches for sure.
    Last edited by 80's_Metal; 04-01-2019 at 12:31 PM.

  20. #40
    Mojo's Minions LLL's Avatar
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    Default Re: I got a new amp today.

    Is that the new Marshall PC? Does it run Windows 10 then?
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