Gamecube digital cable VGA / RGBHV mod: soldering problem

[Kadano]

One of the two Gamecube VGA cables I have has been going faulty lately. The monitors I connected it to said “out of range – 157 khz / 0 hz”, so I guessed that probably my sync soldering was rather bad.

After some attempts of soldering it back together, I managed to make one of the MX pins fall off (*sigh*).


Pin 22 (vsync) has no connection between MX and PCB now. It’s still possible to solder to the end of the pin that sticks out maybe 1/4th millimeter from the MX chip (I scraped off some of the MX chip plastic to get to the pin), but I can’t solder to the PCB at all (solder won’t stay there).

So far, when I connected vsync from VGA pin 14 only to the MX chip (and not to the chip’s PCB), my RGB interface recognized the signal, but it seems it was improper since the monitors still say “no signal / out of range (0 khz / 0 hz)”.

So, my question is what exactly the connection from MX chip to PCB is for and whether it’s completely necessary. If there is no hope of making the VGA cables work without this connection (that I don’t think I’m able to restore), I’m willing to sell my cable for cheap to whomever can make use of it.

Here is a photo of the current condition I just took:

[andre104623]

Sorry to break this to you but you killed that chip. There's no saving it

[Kadano]

That’s okay, I got four of them for cheap so I still have plenty. Still sad, but at least it wasn’t my only one or something.

What exactly did I do that killed the cheap? Was it breaking off the “leg”? If so, why wouldn’t re-attaching a similar leg do the job?

(Just trying to learn so I can do better in the future.)

[megalomaniac]

Sorry to break this to you but you killed that chip. There's no saving it

....chip is not dead...and it still has plenty of life in it...



the PCB has pads for those H/V pins but they are deadend pads with no traces going anywhere...those pins were never used in that pcb design...

that chip/pcb is still fully capable of displaying component video if you restors the connection where you lifted the pin to add the resistor. just remove the resistor and solder that pin back to the pad and everything is ready for component video...
good luck

[andre104623]

Oh sorry I saw the hole burned into the chip and I wouldn't think it would work again. My bad

[Kadano]

Thanks again, megalomaniac. Your posts gave me hope and I managed to restore the cable to working RGBHV output. Soldering to the tiny broken leg took several attempts, but it worked out in the end. I only soldered to the leg, not to the PCB.
I made sure everything within the plug was stable and glued the housing together with epoxy, both so that it wouldn’t open on its own and so that I wouldn’t fiddle with the plug again.

The cable works just fine when connected directly to a CRT monitor, but hooking it up to an amp (Extron 164xi) gives a very unstable, flickering image. I guess there’s something wrong with the sync or ground.

Right now, I’m using both the original black D-Terminal cable and a white VGA cable I soldered to that.

The R, G, B returns within the black cable which shield the R, G, B signals are wired to the responding R, G, B return wires on the white VGA cable. I checked for continuity several times.

Sync ground (VGA pin 10) is wired to the main plug ground connector. Ground (VGA pin 5) is wired to the black cable’s shield ground (which is connected to the main plug ground connector as well).

I believe that the problem is the white cable. Without the shield around the RGB signals, there might be interference with the sync signals, making them somewhat noisy. So my guess is that by removing the white cable and soldering the VGA connector to the black official Gamecube leads directly should make the sync clean again.

I could also crack my working VGA cable open to see how it’s done there, but to be honest I’d probably destroy it while doing so. Just writing here in case someone has a similar problem. And also hoping for someone being able to confirm my belief about the sync interference problem.

It’s also possible that my soldering on the H/V pins on the Gamecube plug is bad and they are so close to each other that they are causing interference. I don’t think this is the problem because the cable works perfectly well when connected to a CRT directly, but in case the “remove white cable” approach fails, it has to be that.

[Kadano]

Okay, problem solved. I did solder another connector to the cable, but this didn’t quite remove the issue. It turned out that the VGA cables (those blue ones that were shipped with monitors 10 years ago) I used in succession after the switch caused the problem. Exchanging them for thicker one made everything work fine.

I guess that the total signal interference is near the level that some hardware can’t handle anymore, and using better cables within that part of the signal chain made it stay below that threshold.