Johnny Mnemonic hand-periodic data glove error

[Chris Bardon]

I've been having this issue on and off for maybe a year now on my JM, but it seems to be getting worse. What will happen is that I'll turn the game on, and everything is fine. Hand goes through its self test, finds its position, and the game starts. Then I'll lock a ball (first one is usually fine), and the movement of the hand is still OK. Then it'll move back to home, and I'll get a credit dot and the game will continue as if the glove is broken. The weird part is, at the end of the game, it'll re-center, and the dot disappears and everything is fine. If I go into the menu while the dot is up, I'll get an ENC Y ERROR on the hand. Now, as for what I've tried to fix this:

-Taken the entire hand mech off and cleaned it
-checked connectors to make sure they're solid
-run all of the in-game tests to see what fails. All the switches are good, and the self test that repeats cycles on the glove appears to be fine for the 15-20 cycles I left it for.

What I haven't tried yet is to disassemble and regrease the gearbox. If it's actually a problem with the encoder, then you'd think it'd be a problem consistently finding the home position, but it moves on both axes no problem. The only reason I thought of the gears was that if the mechanism is getting stiff due to old grease/crud hardering in there, then it might interfere with reading some of the movement of the shaft. It's a stretch though, and I'd rather not take that apart, since it looks like it'd be a pain to get out, clean, and then put back together.

Usually, I can get a couple of games in before it starts acting up, which is all it's usually ever on for, but today it did this to me on the first game I played after it'd been off for a couple of weeks. Anyone have any other suggestions on things to check or possible fixes?

 

[TwilightZone]

What I haven't tried yet is to disassemble and regrease the gearbox.

1. Strongly suggest you check the gearbox. If it hasn't been done already, the grease is very, very old and very, very dry. I've done that on the last two JMs I owned.

2. At the back, there is a rod and an X and Y nut (if memory serves me correctly). Check both for wear. When either wears, it drags and can grind -- then cause an error.

3. It's worth checking all the wires connected to the hand mechanism -- top and behind the game. The hand moves back and forth plus up and down. The wires can work themselves loose over time and make an intermediate connection. I've seen that many times. It's actually not that difficult to remove the entire hand assembly. There are only a few nuts under the playfield holding it in place. Remove all the connectors from the wires, remove the nuts and pull it up and out. I cann't recall if I removed the mini playfield first or not. Basically it's an evening job and well worth it.

Cheers,
Duane

 

[Chris Bardon]

So this problem seemed to go away for quite a while after the last time I disassembled/cleaned the glove mech, but I just ran into it again this morning, and it was slightly different than before. I can't be completely sure of what happened because I wasn't actively looking for it, but I think both flippers pulsed on their own once, and I saw "open coin door to use buttons" on the DMD. Then everything else played fine, except that the game thought the glove was broken again (X encoder error this time). Finished a game, let the glove self-test, and everything was fine again. Played four more games on it just to check, and no more errors-glove did everything it was supposed to.

The message about the operator buttons was really strange though. I tried a game with the door open (and the interlocks both held in) to see if using the service buttons while the game was running did anything strange, and it didn't. Letting the interlocks out and back in didn't seem to have an effect either-I thought maybe if the interlock switch was bad, and the game lost HV for a split second that the hand might see that as an error.

Now, I did just notice that all the hand encoder switches are matrixed on the same column (along with the shooter lane and 3 matrix locks)-could it be a switch issue? Nothing else is acting up on the game, so I don't think it could be, and I don't think I had any of those particular lock switches closed when this happened.

I think the next step is just to clean the encoder optos again and see if the problem goes away. Still, it'd be nice if I could come up with a reliable repro for it, but I just ran another 20 cycles of the continuous glove test, and all of them were fine. Anything else you guys can think of that might help?

 

[Menace]

That glove design is a complete pain in the arse and flakey as all hell. Don't be surprised by these sorts of errors once in a blue moon, you'll chase your tail around and around and get nowhere. Only worry about errors if they are consistently showing up. You can't do much about a poorly designed mech unfortunately....

D

 

[Chris Bardon]

Good to know- I suppose I'll just keep an eye on it and see if it crops up again. TOPL at my place tonight, so I'll just get them to beat on it and see if it holds. I do have the replacement nuts for a rebuild, and I am still meaning to take apart the gearebox at some point, but I just haven't had the free time. Eventually I'll get to it-it may be when the kids are bigger, but I'll get to it

 

[Pharoah007]

I know my JM has perma credit dot for glove switch.

a local operator said he removed all the glove in hand switches due to problems and never had a problem after.

If you know Geoff from Pinhead Amusements, he is the man who knows