GI issues

[robm]

n my WH20, i have the GI around the slings and return lanes out.  I seem to recall at some stage they were very dim.

 When i measure AC from GND to a socket in this string, i get 7v AC.

When i pull the plugs from 121,120,119 i get 7v AC all the left hand end ie(pins 7-11) but only 1.5 AC for pins 1-6 for headers 120 and 121. To me this indicates a board issue?

The board has been repaired before with some burn marks BUT - i have reflowed pins and checked continuity between J120,121,119 and J115 and the triacs and every single one buzzes out on continuity as per the schematics - fuses are all OK as well.

Any ideas?

[MartyJ]

What are your actual plugs like?  ie J115, J121 & J120?

Have they been repinned and new connectors?

I would start with repinning J115 and go from there.

[robm]

Replaced all the plugs just now, and still no difference....

[Strangeways]

Checking continuity may not be giving you a true reading. If the copper traces have been compromised they may not be conducting as well as they used to. I would try jumpering a wire from the pins to the next component in the circuit - thus removing the problem of a burnt trace.

Test this by jumpering pins 1-6 for headers 120 and 121.

[shansta]

Rob: In the GI test - do any of the lamps on that side work - or have you lost the whole string?

I don't know the machine - on my PZ you will lose the entire left or right side of the PF - not just slings and lanes? (My plugs are rooted too)

If some of the lamps are working (In test mode) - I would look at the PF wiring / earth?

If none are working - keep going with what Nino & Marty have said.

[johnwartjr]

You have bad data, so let's start with that first. You don't measure AC against ground. You measure one leg of the socket against the other.

The lower playfield on WW (2 bulbs under each sling, and 3 bulbs under each lane divider, 10 on the lower PF) is the yellow GI string. You want to check voltage across pins 3 and 9 of J120 and J121. Measuring the voltage against ground won't give you good results.

The same GI string has bulbs on both sides of the raft in the translite. So, if the string on the translite works, and the string on the playfield doesn't, you either have a broken wire or bad connector.

It's not uncommon to damage traces when rebuilding GI strings. I'm not intending to doubt your abilities - but if you didn't know how to check AC voltages properly, you may not be experienced in this area, so I don't want to assume anything.

IMO, any GI repair needs to have the procedure for continuity tests in this link followed both before and after the repair. The times I've ignored it, the driver board has almost always had to come out and be repaired again, because a trace that *looked* good was not good!

http://www.pinrepair.com/wpc/index1.htm#connect

Scroll down to the section titled 'Again Verify J115 Connector Continuity'

Test the following paths for continuity.

    * J115 pin 1 to ground. Note if this connection is broken, wacky GI dimming can occur.
    * J115 pin 2 to fuse F106 (lower left) to J120/J121 pin 11, to J119 pin 1.
    * J115 pin 3 to fuse F110 (lower right) to J120/J121 pin 7.
    * J115 pin 4 to fuse F109 (upper right) to J120/J121 pin 8.
    * J115 pin 5 to fuse F107 (middle left) to J120/J121 pin 10.
    * J115 pin 6 to fuse F108 (upper left) to J120/J121 pin 9.
    * J115 pin 7 to Q10 top leg (triac lower rt). Q10 middle leg to J120/J121 pin2.
    * J115 pin 8 to Q18 bottom leg (triac upper rt). Q18 middle leg to J120/J121 pin1.
    * J115 pin 9 - key
    * J115 pin 10 to Q16 top leg (triac lower mid). Q16 middle leg to J120/J121 pin5.
    * J115 pin 11 to Q14 top leg (triac upper mid). Q14 middle leg to J120/J121 pin3.
    * J115 pin 12 to Q12 top leg (triac left). Q12 middle leg to J120/J121 pin6, to J119 pin3.

[robm]

Thanks very much for the replies so far - and John, thank you for the pointers on how to test AC - i really have very limited knowledge of AC related stuff. Also a string in the centre of the translite does not work

Shansta - i have GI on left and right of machine above the slings that work OK

Nino - as i'm getting 7.9AC at the pins i think (but don't know) that the traces are probably OK

So i removed plugs 120 and 121 and AC between pins 3 and 9 is 7.9v AC (similar for 1 and 7 and 5 and 10)

When i plug in one of the plugs, this drops to 6.9v AC, then plug both in and drops to 6.0 AC (same across all pairs)

Testing voltage at either side of the legs of a non working socket gives 0.25v AC - same as the working ones....

So from this it seems in my mind that problem is less likely to be board related and maybe a shorted bulb in the string - or am i barking up the wrong tree?

[shansta]

Rob - please test the lower PF illumination in the GI test menu.

According to John (Who knows his shit backwards BTW) - this is the slings etc plus 10 other GI lamps on the lower half of the PF.

Same circuit should also give you the globes next to the raft in the backbox. (Is this the backbox string that is not working?)

You really need to find out if this whole "yellow" GI string is dead - or just parts of it?


Assuming it's the whole lot (it sounds like it from here).

Do the continuity checks that John outlined. Remove all the connectors from the driver board before you test.

i.e. * J115 pin 6 to fuse F108 (upper left) to J120/J121 pin 9.

So - Pin J115-6 should be a circuit with Fuse108 and ALSO Pin 120/121-9

Test all 13 points listed.


Post back what you get. (Or don't get?)

[robm]

Thanks heaps guys - prob solved, below is the process

Followed shanstas advice above, triple checked continuities - and still all OK

Then sent to the GI test and noticed that the lower pf GI test illuminated the upper pf and got me thinking there might be some screwy wiring (as the 120/121 had already been replugged before i had the machine, then i just replugged again to make sure, and put the wires back where they had been)

Decided to look in the manual at the wire colours for 120/121 and 120 was all out (ie: wires at every 2nd pin, when they should be in two groups of three), re pinned the plugs to the appropriate wires and all the GI works now.

Thanks heaps for your help as i now know how to test AC properly as well as understand GI circuits a bit which was always something i was very shakey on.

Right, off to get that elusive Vacation Jackpot that i still haven't got!!

[shansta]

So the old operator screwed the machine... Seems to be a common pinball theme!

Nice work! 

[johnwartjr]

Here's another tip that may help with future GI issues on WPC games

Across all WPC generations (WPC, WPC-S, WPC-95), WMS used 5 GI strings.

The strings are colored - brown, orange, yellow, green and violet

Each string has 2 wires - one solid, and one striped - so brown, and white with brown stripe, for example.

One connector supplies the backbox insert, one connector supplies the playfield. It's done this way so you can completely remove either part by itself if needed.

Not all games used all 5 strings on the playfield, or on the backbox. Some games used 3 strings on the playfield, and 3 on the backbox, or all on the playfield, and one on the backbox etc.

The connectors should always be pinned as follows, *if* the wire exists in the GI plug. Manuals are wrong often, so it's easier to just write down this standard than it is to look it up in a manual you may or may not have, or try to find a PDF.

Pin 1- Brown
Pin 2 - Orange
Pin 3 - Yellow
Pin 4 - Key
Pin 5 - Green
Pin 6 - Violet
Pin 7 - White-Brown
Pin 8 - White -Orange
Pin 9 - White-Yellow
Pin 10 - White-Green
Pin 11 - White-Violet

Enjoy your WW - it's one of the favorites here!

[robm]

Excellent information again John, thanks heaps

[robm]

So just thinking a bit more about john's info above.

Does this mean if for example one string was out due to a board issue, and there were other spare pins on the plug not being used (as not all machines have the same no. of GI stings), that you could swap them across

EG: Pins 1 and 7 had no voltage

Pins 3 and 9 were blank - move the br and br/white wires to these ones and it should work?

Just an idea to get out of a tight spot.

[johnwartjr]

Won't work. The CPU turns the particular strings on and off at different points during a game.

Also, the games are pretty well balanced - a certain # of lamps per string so they won't overload.

[robm]

Oh well, thought it was worth asking

Thanks again