PCE Duo won't spin discs after RGB mod

[kazoozle]

So I just installed Voultar's RGB board into my Duo original, and while the mod works fine (aside from a little noise but I'm trying to reach out to Voultar himself about that) I can't boot into the CD BIOS anymore. CD BIOS was booting just fine before I installed the mod. One weird thing I noticed is that pin 61 of IC501 buzzes continuity with the pad next to it (not pin 62, a little empty pad on the board) and I'm not sure if that's normal. I tapped 5V from pin 61 to power the RGB amp so I'm not sure if that's something I did and if that's the cause of the problem or if it's supposed to do that.

Could that cause the CD BIOS not to boot? What are other issues that could cause this and how can I fix them?

[Keith Courage]

Was this installed inside a R or RX? I've had a few broken R and RX Duos mailed my way over the years where I've seen a number of RGB amps installed by tapping 5V from the D91317GD chip. In each case the D91317GD had gone bad and CD Bios would no longer load.

If this chip(D91317GD) Is the one you are talking about for tapping your 5V power, then your chip might unfortunately be bad in which case it can be expensive to replace since the only place to source this chip is from other DUO systems. Not to mention finding someone willing to change out such a large chip.

The word really needs to be spread around that's it's not okay to tap 5V from the D91317GD chip for a RGB amp install.

[kazoozle]

It's an original black Duo, not an R or RX, Voultar tapped D91317GD in his video so I figured it was okay. How can I verify that the chip went bad?

[Keith Courage]

I honestly can't think of a way to test if the chip itself is bad. Maybe someone else can chime in with a more full proof way to test.

For the DUOs I had sent my way with this issue, I had sent a few of them to thesteve(he is retired from game repair now)and some owners just decided to sell their systems for parts as they considered it too costly to repair.

There still could be a chance you have bad traces or corrosion somewhere else on the board causing the no boot CD bios instead. Just seems to point to the D91317GD as the problem as everything was working fine before the install.

Have you tried uninstalling the amp to see if the system works correctly that way?

[kazoozle]

Okay so I just reassembled it thinking that I'd just try booting the BIOS from my Everdrive once it arrives, tried it again for shits and giggles and wouldn't ya know it? BIOS boots now, I have no idea what I changed.

But now discs won't spin for some reason. They were working before the mod, the system is recapped, I didn't touch the pots. It's always something with this thing

[Keith Courage]

Whatever the problem is that is causing the CD bios to not Boot (without the everdrive) must be also causing the CD drive to not work.

Something completely random that I just remembered, double check that both of the 7805 voltage regulators in the duo are still supplying 5 volts. I've come across a few Duos every now and then where if one voltage regulator quits working, the CD bios will not load.

[kazoozle]

To clarify: I don't have the Everdrive yet, the BIOS boots on its own now, but the disc won't spin. I'll still check the regulators tomorrow and update here when I get the results

[Keith Courage]

Oh, sorry my mistake about the everdrive.

Well that's a good sign that the bios at least loads up again. So most likely the D91317GD chip is still good.

Does the CD bios say (please set disc) if hitting run without the lid being closed?

Has the DUO ever had a capacitor change? Probably needs one if it hasn't been done yet.

[kazoozle]

Yep, the BIOS acts totally normally, I hit run, it says please wait, and then the disc never spins.

Yes it has been recapped already to fix CD problems before, drive worked perfectly after the recap

Edit: I tried testing the 7805's, and I'll admit I'm not quite sure if I did it right, I've only used my multimeter to check continuity before so I tried googling what pins to probe, but if I was looking at the right pinout then I'm not getting anything from the output pins, but that can't be right if the BIOS is loading, right?

Edit 2: I moved the laser assembly by turning the gears and it won't return to the spindle when I hit Run, seems like the motors aren't even working

[michellybells]

Testing a 7805 with a multimeter is pretty easy. If you're looking at the front of the 7805 (writing side) the middle pin is ground and right pin is output. Just set your meter to measure voltage mode. With the system on (probably don't need to hit Run to try booting, but it I don't think it would hurt any if you did) touch your probe to the pins. (I believe the black probe on middle (ground) and red probe on right (output). If it's working correctly you should see just about 5 volts being measured. It can be just slightly lower or higher, but probably not more than like +- 0.5v difference. (Note, if it says -5 volts, then probably I got the probes reversed.) If you see much less than 5v (or 0v lol), something is probably wrong. If something is wrong, try checking the left pin (input) to see if any volts are coming in to the 7805.

[Keith Courage]

I won't bother with testing the 7805 regulators because they should be fine since the CD bios is now loading. I was only mentioning to check the regulators because I thought the DUO was just booting to a solid white screen(no bios screen).

Your problem could still be caused by a faulty trace or shorted via on the board. Two common places for this would be vias under the Hu card slot or some small vias near the two 47UF caps and CD loading light.

Sorry I can't be more specific as you need to look really closely for corrosion. Sometimes time holding the board up to a light can help as you can see broken traces that way as well.

[kazoozle]

I finally found some time to work on it some more. I loaded up the BIOS on my Everdrive and the same thing happened, so the BIOS has nothing to do with the issue. Only obvious damage I could find is shown in the picture, but I'm not sure if that was there before I installed the RGB mod

[Keith Courage]

You might want to ground those pins to see if it fixes your problem. I have marked which pins are Ground in the picture for you. (blue pins) should all be grounded(you can just bridge them together), but the pin marked with Red in the middle should not be grounded as that pin has a trace that goes underneath that chip. Looks like some ground might be touching that pin so make sure it is not.

[kazoozle]

I just checked continuity and all of those blue pins are already grounded and the red pin is not, so those seem to already be working as intended, I don't think this is the issue. Upon another test I can hear a faint ringing or whining coming from the disc drive when I try to load a disc, almost like the motor is trying to start or something is trying to move

[Keith Courage]

Does the CD bios ever say please close lid if the CD lid switch isn't pressed?