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Nintendo 64 PAL – No Signal After Reassembly

kiltro

Hello everyone!

I have a PAL Nintendo 64 with the following issue.

When I first received the console, I disassembled and cleaned it. It worked fine.

Video quality was not great, so I replaced all electrolytic capacitors. The console still worked and I could play games.

After final reassembly in it's case, it started showing “No Signal.”

What I did so far:

Disassembled again, this time also removing heatsinks.

Cleaned everything again: card slot, AV cable, jumper pack contacts (even with 800-grit sandpaper).

Reflowed electrolytic capacitors and main chips: CPU, RCP, PIF, DENC, and jumper pack connector pins.

Tested various points with oscilloscope (I can share waveforms if needed).

Swapped my Expansion Pak with a new Jumper Pak.

Replaced power supply.

AV cable is brand new, so I don't think this is the cause.

Tried inserting/removing cartridge and jumper pack while powered on (as suggested in some threads).

At this point the console still gives no video output at all.

I was hoping that someone can give me some advice or is available to make a comparison between the measurements made on a working console and mine


Here are measurements (in the Gsheet file) and other related stuff

drive.google.com/.../1_iCxMZg6JVUPDNlzgr-V5CmYrW0aUk71


Schematic of one of the NTSC versions. From what I see what differs from mine is from the video encoder to the output connector.

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  • 0 in reply to kiltro

    Okay, a more substantial update for you.  I took the N64 apart today.  The encoder I have is the AVDC-NUS.  I did some probing with no cartridge and no jumper pack installed.  I will add a disclaimer here.  I have an old 50MHz analog scope so these pulse trains are at the limit of scope"s capability.  In fact instead of square waves I was seeing triangular peaks.  Anyway, the pins that correspond to D0 through D3 had the same type of signal... and in my judgment their duty cycle was less than 50%.  The pins that correspond to D4 through D7 were 0V flat line.  The pin that corresponds to the SYNC signal had an AC waveform.  It's duty cycle was greater than that overserved on D0 through D3.  The pin that is supposed to be the clock had a sine wave.  I suppose it's really a square wave but due to the limitations of my scope I observed it as a sine wave.  My observations are more or less consistent with yours... it's very possible that all your electronics are fine but a poor contact with the jumper pack or cartridge is messing things up.

  • 0 in reply to kiltro

    I am less inclined to suspect the video cable because the waveforms you observed at the encoder inputs match what I was seeing when I had no cartridge and no jumper pack.

  • 0 in reply to dang74

    Maybe you can check what you have on D0-D6 and screen when:
    - Only card game inserted
    - Only jumper pack
    - Both inserted but no controller

  • 0 in reply to dang74

    Main problem with checking continuity between card pcb and main pcb is that I can't access the pin on the card when it is inserted...

    I would have to trace every pin and see were it goes on the board

    This is one cards that was working btw 

    imageimage

  • 0 in reply to kiltro

    I see what you mean.  I thought there would be obvious visible  traces going to some memory chips.  This looks like a more modern multicart.  The MAXII CPLD for instance didn't come out during the N64 consoles life cycle.  Do you have any old school carts?

  • 0 in reply to kiltro

    For what it's worth I've taken my top cartridge connector off and cleaned underneath it.  When I powered the N64 up with a cartridge and jumper pack installed I had no video on start up initially.  I fiddled with the cartridge connector and at some point exerted some downward force on the one chip closest to the cartridge connector.  Not sure which of these two actions fixed the problem... but now things are fine.

  • 0 in reply to dang74

    Chip closest to the cartridge you mean the rcp?

  • 0 in reply to dang74

    Small update:
    - Tried different cable (the one in the vid)
    - Tried wiggling things around and pressing on chips

    Unfortunately doesn't solve the issue

  • 0 in reply to dang74

    I've also found an older game, Mario 64. The pcb is much simpler so maybe I can try continuity using that.

  • 0 in reply to kiltro

    From the video I get the impression that your cartridge connector doesn't grip the cartridge as tightly as mine does.  It seems like it is very easy for you to jiggle it... but maybe it just appears that way.

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