Family Guy Lamp Matrix Issue

[Biff]

Hi

Just got this machine. When i got it back I noticed some of the lamps were coming on when they should not.

I have done an individual Lamp colum and row test.

When i do a column test, every column always brings on 49, 9, 65, 25 and 57 very brightly (they are all on column 1)

When i do a row test, all rows are okay expect for:

When i test Row 5 - it also brings on: 25, 26, 27, 28, 29, 30, 31 and 32 come on very faintly (that makes it one from each of the columns all of row 4)
When i test row 7 - it brings on: 43, 46, 47 and 41 very faintly

Does that mean that there is a fault on row 5, hence why the entire row 4 goes on dimly? and if I cross check that row 5 with Colum 1 they interface at lamp 33 pirate stand up. I have not yet done a diode check, but the lamp holder looks okay to me. My assumption is, as long as i take the lamp out of the holder, i should be able to diode check across the diode and reverse bias it to make sure it blocks one way.

Could it faulty on the CPU card?

Any other ideas?

Cheers

JB

 

[pinballmania]

Find the lamp row and column connector on the cpu. Put machine into all lamp test. Remove the lamp connector, and connect just pin 1. A group of lights will flash - these are your known good test lights. Now move pin 1 of the connector across to each other pin in turn, which is now testing each output with the know good lights. Any fault will soon become apparent, and you can trace the drive component at fault based on the errant pin. Repeat on the other row./column connector. If all test good, then fault is down below.

 

[Biff]

Okay, will try this thanks. So if i get you right Andy, this will check the PCB components only?

If i do this line by line, i don't think this will show any problems, because on any lamp test i have performed the lamps that are expected to come on do actually come on. So i think, if I just do what you say, i will always see a row of working lights? Would i be right in saying this test alone may not disclose the issues (i don't know how else to say it) a 'leak' from an output that should be off will need a variation of this test? Should i then do a row test, and move the pin across the rows if LEDs stay on other than the row, then has to be an issue at the PCB? Repeat for columns?

Thanks!

JB

 

[cooldan]

/bows low before the almighty legend

 

[pinballmania]

Yes. Run along the rows with the row connector, then the columns with the column connector. This will highlight a PCb problem, or if there is no problem with the PCb.

 

[Biff]

Cheers, yes did that, when i did the columns, always 13 lamps illuminated (should have only been 8) Results were the same for all 8 pins - no differences. Same for rows, no differences there between pins. Tells me it has to be one or more problems in the field wiring or a shorted diode or two. Will just double checked the guide (forgot about that) then will doide check all of row 5, then 7 then column 1. Will also look for shorts etc.

Cheers

JB

 

[pinballmania]

Agreed. Sounds like a playfield problem. Start careful examination of the 13 lights that come on when only eight should.

 

[Biff]

It was a busted lamp holder - two in fact. I found them by measuring in ohms between columns and rows, one at a time (a bit like insulation resistance testing). I think the other issues are down to ghosting. Strange though, even a few of the filament lamps, when i swap them over, pulse very dimly. Is this normal or a sign that the timing is out on that row / column / early days for a problem on the PCB?

Cheers

JB