JVC X'eye repair

[jwo825]

I picked up an x'eye project last weekend. It's got the dreaded issue of the BIOS that doesn't load. The cartridge side works just fine. I've spent all the last week going over it and I'm about to the end of what I can diagnose with the equipment I have. Here is what has been done/tested so far
1) Entire console recapped
2) Every component, IC, connector in the CD circuit has had solder reflowed.
3) checked all voltages. I'm getting 4.94 consistently throughout. Seems a little low, but the cartridge side works just fine. I do not have the OEM adapter but the one I do have is 9V 1.5A. I have tried a CDX adapter and the issues persist.
4) Spent the better part of this week so far checking continuity across the entire system. I can find no broken traces or loss of continuity. The boards are immaculate.
6) both motors have been verified to work.

I've done a lot of reading and there seem to be plenty of cases of this, but no real solution. One person had a corrupt BIOS and was able to fix the system by swapping it with a good bios. I have tried to boot a known good BIOS from a flash cart (Everdrive) and get the same problem. Am I correct in assuming that this would rule out the on-board BIOS being corrupt?

That's where I'm stuck for right now. I'm guessing it's maybe one of the handful of ICs in the CD circuit that has gone bad, but I don't have the means to evaluate the circuit any further. There's not a whole lot of info about the system in general so I'm just kinda throwing this out there to see if anyone has any suggestions of possibly leads where I can find any more info.

Thanks.

[SamIAm]

I have an X'Eye with a working bios, and I can tell you that the region-cracked X'Eye bios floating around does not actually work in the system when paired with my Everdrive.

However, I believe I've gotten the JP Mega CD 2 bios to work, although I can't say with certainty which exact version it was. I can say with certainty that something worked, as that's how I played a good few JP games.

[citrus3000psi]

With no cart inserted and turned on does the power light work?

[jwo825]

Samiam, thanks for the tip. I downloaded about 9 different BIOS files and none would boot. The x'eye one I have is the normal 2.00 with no crack.

Citrus, yes, I get the powers light. But the access light wil never come on. The laser will return home if I manually move it away. The spindle will also jog briefly when the unit powers on.

[citrus3000psi]

I fixed a wondermega for someone that was having startup issues on the cd side. Power and access lights wouldn't light up so the reason I asked. Check out the voltage regulators and make sure they are outputting the correct voltage. One of the regulators outputs higher than 5v on the wondermega. On this unit a dead PNP transistor was keeping one regulator in shutdown mode.

[jwo825]

I fixed a wondermega for someone that was having startup issues on the cd side. Power and access lights wouldn't light up so the reason I asked. Check out the voltage regulators and make sure they are outputting the correct voltage. One of the regulators outputs higher than 5v on the wondermega. On this unit a dead PNP transistor was keeping one regulator in shutdown mode.

There is only one regulator on the x'eye. It does have 4 legs, though. I haven't seen that on any other console. 5V was the highest current I found on any of the components I've checked. I'll also admit that I'm just a hobbyist that can trace a schematic, not an electronics expert. The schematic is easily found online. I think Console 5 is where I downloaded it. Maybe you can make more sense of it than I.

[jwo825]

here is a link to the data sheet for the voltage regulator.

https://utcdn.utsource.info/goods_files ... Q05RF1.pdf

[citrus3000psi]

There is only one regulator on the x'eye. It does have 4 legs, though. I haven't seen that on any other console. 5V was the highest current I found on any of the components I've checked. I'll also admit that I'm just a hobbyist that can trace a schematic, not an electronics expert. The schematic is easily found online. I think Console 5 is where I downloaded it. Maybe you can make more sense of it than I.

That extra leg is for a shutdown mode. The wondermega I worked on had 4 regulators.

[jwo825]

I don't seem to be having a power issue. It seems to be not booting from the bios. Reading the manual, the boot sequence goes something like this:
1) If a cartridge is loaded, then the main processor just executed that program.
2) If no cartridge, the main processor renders the static CD screen,
3) the BIOS ROM (IC104) loads the necessary instructions into the RAM (IC 105)
4) There is an internal check of components, a circuit test, I suppose. (I have been unable to find a list of all the checks performed)
5) The CD player program is initiated. This is where the animation starts.

I know the issue is a lot more technical than that, but that's the gist of it. It seems to be hanging up on either step 3 or 4. I've checked and can't locate any breaks in continuity. I've tried loading a BIOS from flash cart as well and I get the same result. That's why I don't suspect a bad BIOS ROM. I'm starting to think the RAM chip may be faulty.

[mvsfan]

Those connectors between the main x eye board and the cd sub board are Bad. I had 2 xeyes that wouldnt start up and all i had to do was take those connectors apart, spray some contact cleaner in them, and join them several times to scrape the corrosion off the pins. open them up again, let it dry, put it back together and test.

[jwo825]

Those connectors between the main x eye board and the cd sub board are Bad. I had 2 xeyes that wouldnt start up and all i had to do was take those connectors apart, spray some contact cleaner in them, and join them several times to scrape the corrosion off the pins. open them up again, let it dry, put it back together and test.

I will try contact cleaner. I have already scrubbed them with alcohol and tested continuity, but I will try this for good measure.