Electric shock from Xplorer, fried motherboard, sadface.

[sickle]

A few days ago, I thought I'd got a bit of an electric shock when plugging the parallel cable into the side of an XPlorer FX cart. It was pretty late, I'd been up a long time, I figured I'd just pinched some skin or something and ignored it.

Then last night, with a different XPlorer cart, I went to plug it in and my PC froze up. After some fiddling, it seems all of the peripheral ports have fused out (tried with a spare PSU), and the system won't boot. Thankfully it seems the drives and GPU are fine, but I'm not getting output from the builtin VGA or the PCIE graphics.

It's not a massive deal; I don't buy parts I can't afford to replace at a moment's notice but at the same time I'd really rather this didn't happen again. So I guess my question is what happened? How can I prevent this from happening in the future?

Was it static buildup from the TV (big ole' CRT thing)?
A dodgy old playstation? (though it does seem remarkably unharmed, as does the Xplorer)
Was it my motherboard? (Gigabyte G31M ES2L, about 6 years old, have had no problems with it otherwise)
A sign from god to do more worthwhile things with my time?

Any help, suggestions or advice would really be appreciated.
Cheers =)

[sickle]

Heyhey, just a wee update incase anyone's actually reading/cares/wishes to laugh/is curious.

I was speaking with nocash who pointed out that the PSX's ground is floating and mentioned his father has a TV which likes to shock people through the headphone jack. Replacement mobo arrived, so I got out the multimeter and started testing everything.

From the plug socket -> strip plug -> power cable -> PSU -> mobo/shell -> LPT port -> LPT cable -> XPlorer -> PSX Chassis -> PSX Composite cable's outer shell -> RCA jacks' outer shells, everything is nicely grounded. (Though obvs, the PSX is not).

On the TV side of things however, the chassis is not grounded. The outer shells of the jacks are all well connected, but not grounded. I hadn't really expected this, since in the UK, everything is generally pretty well grounded and by law comes with the plug pre-wired.
(With the exception of those 2 prong plugs used by radios and the odd console like the PS1/2/XBox 10-15+ years ago)


With that in mind it seems like there was some kind of potential buildup (as is apparently fairly commmon with TVs) which grounded through my PC as I attempted to plug the XPlorer (with cable) into the back of the PSX.
(I'm guessing if the cart had already been in, and I was plugging the cable into that, ground would've been closest and that would have been dealt with, but since I was plugging the cart itsself in, some other pin bore the brunt of the shock).


So I've been toying with the idea of using a video capture card. Then at least the PSX's chassis is always grounded through the outer shell of the video's RCA jack to the PC's ground, hopefully allowing me to plug/unplug the Xplorer at will.

Is that a reasonable idea?
Or are there likely to be further complications from the PSX's ungrounded power board?
Would it be a good idea to add another socket to the PSX with just a ground pin, since that'd likely be the path of least resistance?

Cheers =)

[Shadow]

Sounds like your TV is a hot chassis type. Just punch a hole in your PSX and ground it to the PC chassis
Actually, most if not all TV's will be floating, so that might be a good idea.

I have had my Xplorer give a static discharge (because one has more potential than the other, hence an electron flow is generated), but I have always touched the outer DB-25 connector from the PC to the outer DB-25 connector of the PSX to ground it. I've also noticed that if you boot X-Flash and flash the EEPROM with CAETLA, it wont boot if the DB-25 is connected after flashing. So you need to unplug the Xplorer, boot X-Flash again, re-insert the Xplorer (without the DB-25 connection), press R2 or whatever to re-detect comms and then re-flash again.

[nocash]

Using a video capture card instead of the TV should be fine. As you said, that would give you a common GND connection. And especially, you would get rid of the TV (which was probably responsible for the damages).

Just GNDing the PSX, and still using the TV might work, but it might also shift the problem: You might still get something destroyed when connecting/disconnecting the A/V cable between grounded PSX and un-grounded TV.

And GNDing the TV itself, by replacing its 2pin power cable by new 3pin cable: It would sound reasonable to me, but I am not really comfortable about messing with high-voltage stuff (especially CRTs with a dozen of kilovolts, with the voltage in there even when switched off). Not to mention that it'd require some case modding to get the cable secured mechanically.

Btw. the TV would seem most likely, but... to did you try using a screwdrive with phase-tester to get an idea where the voltage came from?

[sickle]

@Shadow:
Cheers, it's actually good to know that others have had odd spark as well.

I guess since I'd normally have the cable already attached when plugging it in (say I trashed it or something ), it couldn't discharge so easily through the DB25 shell like you do.

Making sure there's always at least one point of contact to the PC seems to be doing the job for now.

Worth putting out a warning when selling PSIO maybe? I've had similar issues connecting other devices.

Oh yeah, as for not having to double-flash the cart (for an FX anyway), I find having the cable pre-plugged into the cart helps as it'll sometimes jam up xflash when done after. Also, not starting XFlash from within caetla, another part of the ROM is fine, but using "Game Start" or "CD-ROM" tends to cause issues.
Flicking the cart to "ON" after XFlash has loaded might also help, and if it's a dead cart, lining up the pins perfectly before you plug it in. A sloppy insertion (luls?) seems to cause it to jam up a bit sometimes too.

@Nocash:
Yeah, it seems to be fine so far. I've added an m/f jumper cable pair too just incase - so there's always a point of contact.

I don't have a (working) phase tester to check with the TV, but certainly the shells of the RCA/SCART/RF jacks are all connected - just not to ground. I'm not comfortable messing around in there either - a bit clumsy at the best of times.

In the absence of a phase tester, I did try just waiting and touching various parts... y'know, the scientific way... but it happens overall so infrequently that I wasn't really feeling anything.



Totally appreciate the help from you both, massive thanks =)


P.s. I'm wondering now if consoles being ungrounded is a deliberate design choice. If like Shadow suggests, a lot of CRT's have a 'hot chassis" but consoles were all grounded... fumbling fingers might go to connect the console to the TV only to have it discharge through whichever part of the cable got there first?
Whereas if they're both floating, no biggie?

Found some pretty interesting reading on the subject:
http://forum.allaboutcircuits.com/threa ... sis.35080/
http://www.ohio.edu/people/postr/bapix/GFCI_.htm

[sickle]

For the sake of completeness - about a month in now with the PSX chasis grounded to the PC's chasis. No nasty shocks or surprises =)