Nintendo 64 PAL – No Signal After Reassembly

dang74 Sorry to bother you, do you have any updates?

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.

I'll try what you suggest.

In the meantime, might it make sense to order another video cable?

As I said, mine is new, but it's not original, and I see some people on Amazon saying things like "poor quality" or "no signal" (actually, a fairly small percentage of reviews)...

What I tried was testing the resistance between the connector pins and the cable's RCA connectors, and I got about 4 ohms for each signal, so it should be fine... but who knows?

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.

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

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 

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?

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.

Chip closest to the cartridge you mean the rcp?

Yes

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

Unfortunately doesn't solve the issue

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RE: Nintendo 64 PAL – No Signal After Reassembly

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

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

Good.  Hopefully it is easier to see where the traces go.

I'm testing resistance directly on the cartridge PCB pads and the terminals on the motherboard. I still have to finish, but for now I'd say it's good, I'm getting 0.4 ohms. On some lines, tilting the game PCB towards me increases the resistance to 15-17 ohms.

It's a bit tricky to be sure, but testing between the cartridge and the pins of the upper connector (the ones that fit into the lower connector) shows that the resistance doesn't change even when tilting the cartridge, so I assume the problem lies in the interlocking system between these pins and the plugs in the connector under the motherboard.

That said, it could be completely normal, since it's practically impossible to get the cartridge to be in such an inclined position without forcing it. Also, with the console turned on, even tilting it back and forth still causes the problem.

Another note... yesterday the screen I'm using for the test suddenly stopped working... lol, the screen's power supply suddenly stopped supplying 19 VDC, now I'm using the benchtop power supply to turn on the screen.

dang74  So, I've measured all the connector to mainboard connections and they seem fine to me... something like 0,4-1ohm (there is probes resistance in there too)

Now I'm not sure where to look...

I see some people have problems with C73 (it's the 68u near the power swtich). Mine is new, and I have checked it measure 68uf, but what do you measure with resistance mode on his pins?
I get something like 280ohms

Looks like it isn't the cartridge connector then.  I will measure the resitance across C73 and/or the capacitor near the power switch tonight.

I measured the resistance across C73 and it was 283 OHMs.

That's ok too then...

Maybe I should try a crt tv, if I can find one.

Do you have activity o D4-D6 whith game and jumper pack inserted?

Okay, I will check tonight.  If you are getting activity D4-D6 that is a good sign.... and maybe an older CRT that doesn't go blue at the smallest issue can give some clues.

I'm not. That's why I'm asking if you are sure there is on yours

Well I tried probing D4-D6 with cartridge and jumper pack installed.. and I did see some activity... but when I reset its low again... so it's possible that the act of probing is disruptive.