System 1 help needed !

[g-man]

I know Menace is one of the resident Sys 1 experts, but in case there are others, I'm just throwing this out there.

Feel like chiming in with a possible solution ? Go right ahead.

Trying to get my Close Encounters ( solid state) up and running. Has a Ni-Wumph (older model) and a Rottendog power supply. Driver board is original.

I'm pretty sure I've got a couple of pooched transistors, both are MPS-U45 transistors, because my tilt relay is stuck on ( I've cut the power to it ) and my target bank reset isn't working although it fires when shorted to ground.

However, here is the latest problem and the main reason for this post : I have no playfield ( CPU controlled ) lamps at all. However, when I ground the transistors individually, they light up. So, what gives ? I've had a few transistors fry in the past, but every one of them ? If not the transistors, then I guess it could be the IC drivers, but every single one ?

What's up with that ?


I guess my second question is, does anyone know a local source for CEN-U45 transistors ( which are apparently the replacement for the MPS-U45 ) ?

Thanks muchly.

 

[Menace]

I've actually never worked on a sys1 yet, only sys80 but this controlled lamp symptom is weird as I was under the impression mpu and driver are all on one board for sys1? If the controlled lamps light up when you ground the transistor that to me indicates a logic issue up-stream. Where it's all on the same board it can't be a connector issue... Could it be something to do with cutting the power to the tilt relay?

As for the CEN45U's, there is no local source for small qty. I distribute these at my work, but only in large qty unfortunately. I sold a bunch to Ed @ GPE years ago though, maybe he's still got some?

D

 

[flyer666]

check the 74175's on the board

Here is a place for your needs


Mikes arcade (http://www.mikesarcade.com)

D40K1 (D40C1, NTE268, NTE272)

SKU: TRNS268
$7.25

 

[sylvain]

Did you check the MPU to Driver harness ?
If there was any corrosion on the original MPU in the past, it is quite possible that some of the pins
in that harness are corroded or broken...

Also check the game over and tilt relays, one of them interrupts some lamps if I recall.

Of course, these Sys1 also need a ground mod...

Cheers,
- Sylvain.

 

[Grauwulf]

Ed at GPE still has CEN-U45's, I just bought a few from him recently at a good price. If your lights and stuff are working if you ground the transistors, then you need to look upstream as was previously mentioned. also check the interconnect cable between the MPU and driver. If it hasn't been re-pinned before, it probably needs to be.

 

[g-man]

Thanks for all the responses.

Yes, the connector from the MPU sounds plausible. I am at a bit of a handicap since I have a manual for the game which does not have the schematics. Even the pinrepair guide is a little vague in this area. Is there a single wire in that harness which is responsible for every controlled lamp ? The harness has not been repined, but unfortunately, all my 0.156 pins are trifurcon style.

When I cut the power to the tilt relay and the coil relaxed, the GI lights came on but the controlled lamps did not. So I am assuming that the tilt relay is not the problem.

I have done the ground mods, even the five or six individual mods on the driver board.

I guess I will wait to get some pins and see if that is the problem.

I forgot to mention that I tried a second driver board in it and there were no controlled lamps with it either.

I'm a Bally man. I'm not comfortable with these Gottliebs. :cry:

 

[sylvain]

One of the two transformers also has one bridge rectifier, protected by a 5A SB fuse typically, for the controlled lamps.
Have you checked that fuse ?

and, the Tilt relay does control both the GI as well as the controlled lamps (at least in Sinbad and in Genie, both Systems 1)
on separate contact pairs.

 

[g-man]

One of the two transformers also has one bridge rectifier, protected by a 5A SB fuse typically, for the controlled lamps.
Have you checked that fuse ?

and, the Tilt relay does control both the GI as well as the controlled lamps (at least in Sinbad and in Genie, both Systems 1)
on separate contact pairs.

Fuse rings out okay, but I could put a new one in anyway just to be safe. Also forgot to mention that I replaced the bridge rectifiers as well.

 

[Menace]

Yeah, if the lamps are lighting up when you ground the transistor it's not the bridge. (usually if the bridge goes it takes the fuse with it) I would definitely start with the connector from MPU to Driver for sure, especially where you've swapped in another driver with same result, and then work your way back from there up into the MPU.

D

 

[g-man]

Picked up some 0.156 pins today at Sayal. Gonna re-pin the mpu/driver harness.

Which connector should I do after that ?

 

[g-man]

So an update to this thread:

I repined the MPU/driver harness. When I did that, I found that the 1K,2K and 3K lights plus the 2X and 3X lights came on and stayed on when game was started. Grounding out the transistors would light the other lamps, but the other lamps would not come on during gameplay.

I then repined the A3J3 connector ( houses all the controlled lamp wires ) and upon startup, pretty much every controlled lamp came on ( and stayed on ) except for the 4X, 5X and 7K. These lamps would also stay on during game play.

I have a second driver board and when I swapped it in, pretty much the same thing happened although with a few different lamps.

So, here's where I'm at. After repining, I am finding that large blocks of lamps are coming on and staying on. Those that don't come on, are coming on when grounded. On the better of the two drivers, there is a pattern to the lamps that are not working. It looks like the 12 lamps ( 1K - 10K plus 4x and 5x ) are in 3 groups of 4, so it looks like it may be a chip issue on the driver board. But I tested the individual transistors and did not get the readings I was supposed to, so that suggests that they are bad ( on the left leg I get no reading at all, but the right leg gives the proper reading of 0.7 ). So, aside from the usual WTF ? , I guess my question(s) are:

1) Is it likely that every single individual lamp transistor is pooched or is it more likely that 3 chips chips on the driver board have failed ? Keep in mind that the other driver board also had tons of CPU lights come on which means both boards would have to have multiple blown transistors or chips.

2) Is it more likely a CPU problem ? I have a ni-wumph in there, but it is an older model and I bought it used ( supposedly working) from somebody years ago.

3) If it is a massive transistor or chip issue, given that I've also got a couple of blown MPS-U15 chips on the board, would I be better off just buying a $60 Rottendog replacement ? (Transistors would set me back $10 to $15 anyway, so the board would only cost an additional $45-$50 )


Thanks, eh.

 

[g-man]

Quick update before I hit the hay.

As I mentioned previously, I have repinned the MPU/driver harness. Lamps still locking on.

I also repined the driver board connector which runs to the lamps. They still locked on.

I replaced one of the 74175 chips to see if that would make a difference, and it didn't appear to. Lamps still locking on.

I replaced a couple of individual transistors to see what effect that would have. Lamps still locked on.

So after replacing chips, transistors and repining, I have seen no improvement ?

What else is there ? :FP: If this was a Bally, the problem would have been fixed long ago.

Should I just buy a $60 driver board ? Is it possible that wouldn't even work ?

M'aidez !

 

[sylvain]

Some info here:
http://tuukan.fliput.net/sys1_en.html#driver

Hmmm, perhaps time to suspect the MPU. Make sure the Ni-Wumpf switches are set for the correct game.
I would also triple-check the wiring on the repined MPU-Driver harness in case some wires are reversed.

- Sylvain.

 

[g-man]

Thanks Sylvain. I will check the harness over tonight.

I forgot to mention a new strange behavior.

When I first replaced the 74175 chip and a couple of transistors, there was no change....the 2x, 3x and 3K-7K lamps still locked on. However, when I powered the game off and then on again, the 3x lamp did not light. But then after another on/off cycle, it lit. It's not a lamp bracket issue and wiggling the harness wire didn't bring on that behaviour, so I'm further perplexed why that would happen.

 

[Menace]

It's a GTB Sys1. Everything to do with their behavior is perplexing.

D