N64 VDC-NUS damaged?

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pyroman512
Posts: 43
Joined: Sat Jan 14, 2017 3:40 pm

N64 VDC-NUS damaged?

Post by pyroman512 »

I opened my N64 yesterday to install the UltraHDMI kit and that actually went smoother than expected. But I wanted to redo the voultar RGB amp board I had installed before and fix my crummy wiring job. In a nutshell the Blue channel is not working and the VIA is damaged. I pulled the wire off the board and tried composite only to see if the problem was corrected and it is still showing the yellow tint and the blues are showing up black.

Is there a way to tell if the chip is permanently damaged? I used my hot air station to desolder the vdc-nus chip and reinstall. And I added some extra solder into the via and tested continuity between the resistor at that via and pin 21 (blue).

The UltraHDMI portion is working fine, the self test reports 0 problems. But my analog video is not working. Any help is greatly appreciated.
Xaranar
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Joined: Mon Mar 20, 2017 8:43 am

Re: N64 VDC-NUS damaged?

Post by Xaranar »

Might seem like a daft question, but have you checked to see if your blue channel has a short to ground? I only ask because that has been the case so many times with me when one of the colours isn't working, and it's usually the blue for some reason.
pyroman512
Posts: 43
Joined: Sat Jan 14, 2017 3:40 pm

Re: N64 VDC-NUS damaged?

Post by pyroman512 »

I did check and it was shorted to ground. It isn't currently and the problem still exists. Was it possible I fried the DAC?
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Star1
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Joined: Thu Dec 03, 2015 9:28 pm
Location: Norway

Re: N64 VDC-NUS damaged?

Post by Star1 »

You could just try to solder a jumper wire directly from the NUS pin to the rgb amp. If it does not work that should pretty much settle it.
pyroman512
Posts: 43
Joined: Sat Jan 14, 2017 3:40 pm

Re: N64 VDC-NUS damaged?

Post by pyroman512 »

If anyone else sees this and has this problem I have a few suggestions.

I bought a "dead" n64 on ebay and switched the VDC-NUS out with my presumed dead one. And it had the same problem so naturally I was flustered at what to do and started prodding around. There was no cross between the blue signal and ground anymore, but the picture still lacked blue on composite and through voultar's board. I checked the resistance on the 110 ohm resistor and it was reading ~80 ohms. I then disconnected the wire at the via for the blue signal and the resistance went back to 110 ish.

I'm not really sure what caused this cause like I said earlier I had damaged the via a little bit. Everytime I tried to solder the wire back on the blue signal was shorted to ground. I got a smaller gage wire and the problem went away.

All is well now. So if you think you fried your chip.. Check the resistance and disconnect the wires and make sure the resistance is within 5% of 110 ohms. Use a smaller wire than the 22awg I used. And then check try swapping the vdc-nus chip if all else has failed you.
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