Problem: I go into the lamp test in the test menu and light each lamp one at a
time. When I run the lamp test I see some bulbs will light when they are not supposed to.

Example: The 8x multiplier lights up & so does the extra ball lamp & same thing in reverse extra ball lamp lights & 8x multiplier lamp.
This happens with about 4 different lamps.  

This page might help:

http://www.pinrepair.com/wpc/index2.htm#lamp

Scroll down to "Two Lamps On Instead of One."

Quoted from tinyrodent

This page might help:

http://www.pinrepair.com/wpc/index2.htm#lamp

Scroll down to "Two Lamps On Instead of One."

Thanks for you're help.

Ok this is what I've found, Red-Grn & Red-Blue in the single lamp test all run 2 lights (J135)
Pin 7 red-blue & red-green on pin 6 @ J135.
At this point I've tested all diodes...
So I'm thinking bad transistor, need more help on this one guys.

Diodes can only be tested out of circuit, by desoldering one end. However, transistors can be tested in circuit and that is the next step recommended by pinrepair. In my experience it's not an infallible test but a good place to start. Also in the same section it is described how to determine whether there is a short on the playfield:

Quoted Text

look for a short and/ or bad lamp diode on the playfield. This is easy to test; just remove the lamp matrix plugs from the power driver board (these connections are shown a few paragraphs below). Using the DMM set to ohms, see if the associated row/column wires are shorted to each other on the disconnected lamp matrix plugs (not on the driver board!). If two lines buzz out with zero ohms, there is a short or bad diode on the playfield somewhere.

Yeah I did follow the test for a short it was my first thing I tried, came up ok on the meter.
I also removed each lamp from the chain & it came up with nothing.
If it’s a bad transistor can I not trace the location on the driver board?
The chain that’s bad are using the same wire codes all other wires are fine, I guess what I’m getting at is J135 pin 7 & 6 should be controlled with a transistor location point on the driver board correct?

Yes you can trace from the pin to the transistors but it's easier to look at the manual. The lamp matrix chart tells you the transistor number of each row and column. The transistors can be tested individually as described here:

http://www.pinrepair.com/wpc/index2.htm#trans2

It's also possible there is a short on the driver board between these two pins. Could be messy solder on the header for example.

If the transistors are ok there could be a problem with one of the upstream ICs. I would look at the schematic and test with a logic probe. I don't have a T2 schematic handy, is J135 the row or column connector?

I uploaded, not sure 100% were the correct transistors are...

The first photo might help but it's too small to read. The second photo is just a parts list and doesn't show the connections.

The easiest way to find the transistors is to look at the lamp matrix table rather than the schematics.

There is a (poor) scan of the manual available on ipdb:

http://www.ipdb.org/files/2524/Williams_1991_Terminator_2_Judgment_Day_Manual.pdf

According to this the column header is J138 and the row header is J133. You said the problem has been isolated to J135?
Also the wire colors don't match the pin numbers you mentioned.
So I suggest double check everything and then check it again.

Quoted from tinyrodent

There is a (poor) scan of the manual available on ipdb:

http://www.ipdb.org/files/2524/Williams_1991_Terminator_2_Judgment_Day_Manual.pdf

According to this the column header is J138 and the row header is J133. You said the problem has been isolated to J135?
Also the wire colors don't match the pin numbers you mentioned.
So I suggest double check everything and then check it again.

Yeah I see that, rev is different I guess.
Mine is correct, it has 9 pins not 8, 3rd key is not used.
My column is J138 & uses J135 9 pin.
Transistors test fine...

Hmm that's odd. Anyway I would break out a logic probe next and look at the signals on the board during single lamp test. If you don't have one I'm not sure what else to suggest. Anyone nearby with a spare WPC driver board you can test with?

Quoted from MadIndian

The 8x multiplier lights up & so does the extra ball lamp & same thing in reverse extra ball lamp lights & 8x multiplier lamp.

Looking at the lamp matrix chart, these two lamps don't share either a row or a column.

Quoted from MadIndian

Red-Grn & Red-Blue in the single lamp test all run 2 lights (J135) Pin 7 red-blue & red-green on pin 6 @ J135.

But Extra Ball is supposed to be on Red-Violet.

In cases like this I will go through single lamp test and write the result for each one in the chart. Then it's easier to see any row/column trends.

This is what I get...

Ok I see, there are two different lamps "Extra Ball" is not the same as "Shoot Again". Also the confusion about the headers is because rows and columns each have 3 headers wired identically.

So if all the lamps in these two rows behave identically, there could be a short between the two row pins on any of the three headers J133, J134, or J135. Or it could be a faulty IC at U11 which is shared by these two rows.

To be completely certain whether the problem is on the board or not, you could remove all three connectors and try single lamp test again using test leads, a bulb socket, and a diode as described on the pinrepair page.

WPC schematics can be found here in PDF form but it appears you have it.

http://files.flipperspill.no/Support/Pinball/Other/WMS-WPC-DMD-Schematics-16-9473.pdf

Sounds like you have a latched row(s).

You will have to consult the T2 manual and look at the columns and rows of the lamp matrix to figure which is latched. It's probably just one either the column or row. Consulting the lamp matrix against what you see it should be evident whether is a line across or a line up and down of the matrix that is remaining on. Have you ever played connect 4? It's like that but with eight in a row and with diagonals you don't win.

If your correct of your assumption of it it being J135 pins 6 and/or 7 you will find they are TIP102's Q86 and Q85 respectively which control rows. Test the suspect transistor using Clay's method for in circuit testing of TIP102's. If the transistors check out ok it may be the TTL logic chip 74LS74 at U11 (in fact if both 6 and 7 two rows are latched I am willing to bet it is the logic chip since having two transistors fail simultaneously is unlikely) that is affected. This could be tested with the use of a logic probe.

If the problem doesn't reside there it could be even further up the data stream. Start at the end of circuit as you did with the diodes. Move up to the transistors and test, then the logic chip.


Edit. I just had a look at the T2 Lamp Matrix. Unless you have bulbs out you should be getting more than what is indicated in your pics by a bad row or column. I suggest you recheck your diodes out of circuit i.e. disconnect the lamp matrix plugs. This problem arose without changing a diode I suspect so as to rule out the reversed diode issue.

This is where my focus would be from what I have seen in your pics. Diode or short as detailed here. It would help to know precisely which are all of the lights your having issue with and that all bulbs are in good order.

From Marvin

If that checks out OK, next look for a short and/ or bad lamp diode on the playfield. This is easy to test; just remove the lamp matrix plugs from the power driver board (these connections are shown a few paragraphs below). Using the DMM set to ohms, see if the associated row/column wires are shorted to each other on the disconnected lamp matrix plugs (not on the driver board!). If two lines buzz out with zero ohms, there is a short or bad diode on the playfield somewhere. Shorts happen often from solder drips when someone resolders a coil under the playfield. These solder drips often land on the lamp boards under the playfield, on the header pins, shorting two together.

In your case it sounds like the 8X, Shoot Again are shorted i.e. 6 to7 somewhere. I suggest without knowing the other lights you have issue with, any lights that reside on those rows interact with each other.

Here is the pairing you would get with that row short.



WRT your plug locations J133, J134 and J135 are all parallel. One is for the playfied (J133), one for the head (J135) and one for the lower cab (J134).

Just got home from work, sorry yes everything that you have circled is the problem.
I also don't have logic probe to test U11....

Sounds like you simply have a short in the two lines somewhere. Possibly right at the connector but may be anywhere down the entire two lines. To verify pull the connector off and meter the plug leading to the pf for a short between the pins. Then it's a matter of tracing down the lines. Could be right at the pin header on the board as well but more likely on the connector down to the various lamps on the playfield.

Quoted from necro_nemesis

Sounds like you simply have a short in the two lines somewhere. Possibly right at the connector but may be anywhere down the entire two lines. To verify pull the connector off and meter the plug leading to the pf for a short between the pins. Then it's a matter of tracing down the lines. Could be right at the pin header on the board as well but more likely on the connector down to the various lamps on the playfield.

Already tested for a short on those 2 lines & there fine with no short.

Check it at the pin header for a short. Pull the board and look behind for a corrosion or something bridging the pins. Clean it up with some flux remover if necessary in the header area from behind. If the row transistor was fused you would be getting a complete line. Seeing that your pic is showing 8X and Extra ball but not the 6X tells me it's not a column. The same logic goes for a row. You said you had lamp pairing, but are you saying the entire rows are on with the 8X and Extra Ball lamps? If the entire row is on together it would be a transistor or TTL. Pairing, a short between lines.

You did check ALL diodes on those circled lamps right. Not just the 8X and Extra ball?

Did you also look for the double flash in the all lamps test?

Lamp Diodes (Lamps that don't work or work "twice"). Each CPU controlled lamp will have a diode associated with it. If this diode is bad (shorted on), it will cause other lamps in that row or column (or even another row or column) to turn on. This can usually be seen in the "All Lamps Test". The faulty row or column will light *twice* in a single lamp matrix sweep (once when it should be on, and a second time due to the short on *another* row or column re-lighting it). The lamp(s) in question are on twice as long as all the other CPU controlled lamps.

[quote=191]Check it at the pin header for a short. Pull the board and look behind for a corrosion or something bridging the pins. Clean it up with some flux remover if necessary in the header area from behind.

Amazing, After a few long nights trying to find the problem guess what, yes the above fix worked.
necro_nemesis Wow
You made the job look easy & I can’t thank you enough for your time & fixing this problem.
What a great group of guys on this forum taking the time out helping a noob like myself.
Also thanks to tinyrodent for your time & trouble shooting…

No prob. I'm pretty sure you would have gotten it soon enough. Biggest thing is to think about the operators motivation when "fixing" something is just to get it good enough. The lamps came on albeit at the wrong time which in an ops view is good enough. You probably wouldn't suspect a problem arising from workmanship in most other cases but in the case of these games "repairs" can be suspect. The guy probably thought it was a good idea to re-flow the connections when the board was out, but didn't go the extra step to check what he did.