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Thread: PC Engine Green/White/Grey/Blue Screen not Booting with awful smell

  1. #1
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    PC Engine Green/White/Grey/Blue Screen not Booting with awful smell

    Hi!

    I bought a White (original) PC Engine off ebay and was sad to see it was faulty.

    Overview:
    I am greeted with different color screens each time I power the console on and off with a game inside.

    Also, it smells like burnt electronics every time the console is turned on. (Especially near the back extension port). Which is odd as I am using a stepdown converter that I have used on all my Japanese consoles.

    Mitigation steps:

    Having done some research on this in my late-night repair video searching (We all do it if we enjoy fixing things lol) and I had found out:

    Problems:
    1) The Green/White/ Grey/ Blue Screen boot screen (One color or the other depending on the consoles mood) means
    * Game is not read and the AV works on the console

    2) Checked the Fuse (Fuse does not shown blown)

    3) Checked the Caps and they don't show any corrosion nor bludging.

    4) Check the 7805 (Haven't measured yet but the Power rail seems to be giving off the necessary voltage else it wouldn't display the colors right?

    5) Check the traces for cuts, and or damaged CPUs, or GPUs . (All looked fine, though I have not seen a schematic to find shorts)

    6) Clean with IPA while searching for issues (Done and still no issue, even tried removing the HuCard a bit while powered on and no change

    7) Felt for heat/ hot parts to see if something was shorting but nothing got hot?

    Questions:
    1) What could be wrong with the console? If the following look good:

    A. Good caps
    B. No burns/scorch marks
    C. No blown fuse

    If this thing is smelling like burnt electronics, yet nothing is hot, what could be causing this?


    Looking forward to any assistance that can be provided.

    It's super hard to find PC Engine/ Turbo Grafx16 documentation/ fixing examples on the internet.

    There are a few but, mostly RGB mods and GadgetUk's awesome vids! (You rock btw! keep it up, I am hoping it's not a bad GPU)
    Last edited by Tengugurl; 11-29-2019 at 02:29 PM.

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  3. #3
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    Id return the console and buy a different one if I were you. I would be paranoid by the smell of burning.

  4. #4
    Hollywood Hulk Gohan GohanX's Avatar
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    Yeah, what he said. Generally the multicolored thing means that the system isn't getting a signal from the cart slot, but I don't have the foggiest idea what would cause the burning smell other than a bad PSU. There was someone I was talking to that bought one with the original PSU but the thing was faulty and was putting out 15v. Thankfully it didn't kill the system before he figured it out.

    One thing to try. Push the hucard in all the way like normal, then pull it out just a hair and see if that helps. You obviously can't pull it out much because of the power switch, but sometimes that works on stubborn systems.
    Last edited by GohanX; 11-29-2019 at 03:42 PM.

  5. #5
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    Thanks you two!
    Yeah, sadly I decided to get a partial refund as shipping it back would have costed the same. (yay...ebay.... *meh)

    @GohanX - I saw something on that as well and yeah no luck. (Dang!)

    @ChopstickSamurai - I measured the voltage coming from the PSU and it's 13.4v @_@ from a 9v adapter! (It's a center Negative PSU too if that helps)

    I figured I'd try to fix this system if I could. (TBH I love a challenge)

    That might explain the smell?
    If the Power rail is expecting 9v to step down to 5v and it's getting 13v, crap, I wonder if I fried to board?

    I am not sure of the tolerance on these systems as there is so little forum presence for repair these. (Lucky me it seems lol!)

  6. #6
    Hollywood Hulk Gohan GohanX's Avatar
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    The voltage regulator should be able to handle it, but the catch is that it converts the extra voltage into heat, and the pce doesn't have fans or many vents to dissipate the heat. So you likely haven't fried anything due to overvoltage but something could have cooked just due to heat. I'm hoping that the burning smell might have been the PSU instead of the system itself, try an appropriate psu and see if it helps. A Genesis 1 PSU will work.

  7. #7
    Hollywood Hulk Gohan GohanX's Avatar
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    Also, what seller did you buy it from? The dude I spoke to before also had a psu that read about 15v, I wonder if the same idiot seller is sending stuff out with bad psus.

  8. #8
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    I don't see it in your post but you might have done this already. have you check the Connections on the motherboard to the card slot? i have seen this cause problems. even though they look ok. maybe the cable is cut at some point or Cold Joints etc. I would use a multimeter to check from point to point before going right to a GPU or CPU Fault. Also bad caps also don't always look like they are Bulging or have corrosion on them. I had a CD-Rom Cd-rom where all the caps looked good and it was playing CD's fine but when it came to games it was working but with lots of Graphical errors. So in the end i decided to change the caps and it worked. its now running perfect. so just keep that in mind. also some pictures will help if you can.
    Last edited by Neogeoman106st; 11-29-2019 at 06:01 PM.
    I do Reviews, Hard-off videos and console repair. Check out my Youtube channel here
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    @Neogeoman106st - good idea, I did take a look and they look connected but I might just reflow them. Tbh, I am thinking of taking the heat sink off the bottom of the PCB and reflowing the solder on anything that looks old. Then check connectivity to the ribbon cable and the expansion port on the back.

    The 7805 does have a bit of corrosion around it, I might reflow it and measure it's resistance. (Now to find what it should be lol!)

    @GohanX - The seller seemed like a regular person selling his old console and was cool enough but still sucks regardless. I am picking up a Sega Genesis model 1 PSU to give a proper 9vs to the console to see if that fixes it.

    I'd be super happy if that was the case
    That would mean the random colors that show up on boot would be doing their job.

    *Crossing my fingers that is the case
    For now, I am going to reflow some old solder joints and look at recapping the board.
    Last edited by Tengugurl; 11-29-2019 at 08:38 PM.

  10. #10
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    ChuChu Flamingo's Avatar
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    Keep in mind unregulated power supplies will have higher voltage when no load is applied. Totally normal.

    The electric burn smell is probably ozone from the plastic or capacitors. Capacitors smell pretty horrible when they start leaking. Sometimes you can tell if they leaked cause they are bulging, other times it is below the capacitors out of sight.

    Have you tried washing the case with some dawn dish soap and letting it dry?
    "All creature will die and all the things will be broken. That's the law of samurai."

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