Williams Firepower (Williams, 1980) display segments always on

[kdkal]

Firepower some display segments always on

My Firepower was working fine for years. Then I noticed the "a" segment was out on all digits of the master display and players 1 and 2. Players 3 & 4 are fine, no problems.

I replaced R1 on the Master Display board and it fixed that problem, but now segmants "f, a and b" are always ON for the master display and players 1 and 2. I don't know if they were on before I fixed the initial problem.

Additionally segment 'f' is brighter on those displays than all the other segments on all digits. I checked the 7180's and the 6184's according to Clay's manuals and they seemingly checked out fine.

Could it be IC5, the MC14543 BCD to 7 segment decoder driver? Any way to test it without the power being on?

Any comments or ideas would make this senior citizen so very happy to try.

Thank for thinking about this.
Ken

 

[spalmer]

My Firepower was working fine for years. Then I noticed the "a" segment was out on all digits of the master display and players 1 and 2. Players 3 & 4 are fine, no problems.

I replaced R1 on the Master Display board and it fixed that problem, but now segmants "f, a and b" are always ON for the master display and players 1 and 2. I don't know if they were on before I fixed the initial problem.

Additionally segment 'f' is brighter on those displays than all the other segments on all digits. I checked the 7180's and the 6184's according to Clay's manuals and they seemingly checked out fine.

Could it be IC5, the MC14543 BCD to 7 segment decoder driver? Any way to test it without the power being on?

Any comments or ideas would make this senior citizen so very happy to try.

Thank for thinking about this.
Ken

I could be IC5. I can not think of a way off the top of my head to test it without it powered on. I don't know what shape your machine is in or if you want to put any money into it however, I might recommend another solution. http://www.marcospecialties.com/product.asp?ic=PS-8000-P . These are pinscore replacement LED displays for the system 6. I had a Firepower that had bad displays. Most were starting to gas out and my 100 volt circuit on the power supply was going. These run strictly off of the 5 volt. They do not over task the power supply and you can completely remove the 100 volt fuse. $195 but they look great. You really can not tell the difference. I personally know Brent Davis the designer of these displays. Great support and great product.

 

[jimk]

Could it be IC5, the MC14543 BCD to 7 segment decoder driver? Any way to test it without the power being on?

Any comments or ideas would make this senior citizen so very happy to try.

Thank for thinking about this.
Ken

Since you've already checked IC9 (7180), I would agree the most likely culprit would be IC5 (14543) since it and IC9 are in a common path to your display symptoms. While I cannot tell you how to test it with the power off, with the power on you can check it with a multimeter. I just checked it on my Firepower. On pins 9 thru 17 you should get about 4.5v at those pins where the segment is on and about 0v where they are off. So on yours I say pins 9,10, and 15 would always read 4.5v. Measure between each IC pin and ground. If your machine is properly grounded, the metal side rails provide an easily accessible, adequate ground. Putting the machine in diagnostic mode for the display helps select which segments are lit (i.e., digits 1,2,3,4,...)

Now, I occasionally also get whole digits brighter, dimmer or out due to poor connection at the CPU board (1J7 - which I haven't gotten around to replace), but not individual segments. I suppose a bad R3 could be making segment f brighter, but I'd put my money on a bad 14543.

Hope this helps,

Jim

 

[kdkal]

While I cannot tell you how to test it with the power off, with the power on you can check it with a multimeter. I just checked it on my Firepower. On pins 9 thru 17 you should get about 4.5v at those pins where the segment is on and about 0v where they are off. So on yours I say pins 9,10, and 15 would always read 4.5v. Measure between each IC pin and ground.Hope this helps,

Jim[/quote]

Jim, thank you for your response, it is very much appreciated.

Well Jim, I'm not sure what happened, but I tested the chip as you suggested and found the voltages you mentioned. BUT, the problem with always on segments A&B, went away and only come on when they should. F is no longer very bright, but still very faintly on. I checked all cables, wiggled all connectors, tugged on the appropriate wires in the connectors, pressed on the chips on the display board, turned game on and off a few times, played several games, all with no other change occuring. A&B are now off when they should be and F is faintly on after all that. I did not replace IC 5 since the problem may be something alese at this time.

Usually my pressing on chips or a board would indicate any problem with bad solder joints, but nothing changed when I did that here.
Do you think the faintly on F segement on players 1, 2 and master display is OK, or is it a detrimental problem and I should continue pursuit?

Thanks again , Jim.
Ken

 

[jimk]

Usually my pressing on chips or a board would indicate any problem with bad solder joints, but nothing changed when I did that here.
Do you think the faintly on F segement on players 1, 2 and master display is OK, or is it a detrimental problem and I should continue pursuit?
Ken

Ken,

I don't know if it is detrimental, but it sure would annoy me if it were mine. Given that it went away on its own, it will probably come back sometime. I don't think it will hurt anything in the mean time if it doesn't bother you. With brighter segments I would be concerned with burning the segments. On the other hand if it is a failing chip, who knows what can happen (just saying I don't know).

Sounds like connectors to me. I find pulling the connectors and replugging sometimes helps. I would do this on all of the display connectors as well as the three CPU board connectors.
Here are some other things you can try:

When you say "...F is no longer very bright, but still very faintly on" I assume this is when it is supposed to be off, and when it is on it is OK. If you haven't, try unplugging players 1 and 2 and see if there is any difference.

Here are some more voltages I measured:

With a segment off the input to the 7180 is 0v; segment on is 4.5v
With a segment off the output of the 7180 is -20v; segment on is -99v
With a segment off the display side of the corresponding resistor (1 to 7) is -10v; segment on is -50v

I measured these voltages with the pinball in display diagnostic mode with a "1" on the display. Segment f looks like it's R6 and pin 6 (IN) and pin 13(OUT) of IC9. Your readings should be similar but can be compared to other working segments for verification.

If voltages check out then that seems to leave bad connectors or solder joints. Given that it is happening in three displays I don't think it is a problem with your glass. If nothing shows up in your measurements I would touch up the solder joints on the master board with fresh solder (just a touch to get it to flow), particularly in the suspect areas.

I should have asked earlier, but I am assuming your +/- 100V is OK?

Jim

 

[kdkal]

Hi Jim, thanks for responding. Sorry I'm tardy in getting back to you. A lot of house stuff to get done and then the holiday and all impacted my play time.

Yes, I had tried the unplug/plug of all the connectors -- nothing changed.

Yes, the faint ON "F" segment is when it should be off.

No difference on the main display when I unplug Player 1 and 2 displays.
Your voltage readings were a big help in what to measure.

The -100VDC is -100VDC.

The +100VDC is before the zener and 94.2 after (read at the Pin 10's of the various ICs). The 5VDC is 5.02VDC. The other voltages seem to be mostly in line with yours.

Anyway, I had left the game on and noticed after 10 minutes of so, the faint segment F, just about disappears with about an 1/8 inch in length, and after a half hour it disappears almost completely.

So, it somewhat appears I have perhaps a heating problem in reverse? (It works better as it heats up?). I tried this over a few days and it seems to always start out as faintly on and then disappears as time goes by.

I suppose I could use a freeze spray but I've never used one before. I heard the PC dust sprays are basically the same if I turn them upside down. However, I don't know if it's OK to spray these delicate ICs and if the circuit must be off or if it stays on while sprayed? I imagine a brief spray should work, but I wonder about creating a short since a liquid is deposited for a short time?

Thanks again for your help and it is greatly appreciated. Ken

 

[kdkal]

I might recommend another solution. http://www.marcospecialties.com/product.asp?ic=PS-8000-P . These are pinscore replacement LED displays for the system 6. I had a Firepower that had bad displays. Most were starting to gas out and my 100 volt circuit on the power supply was going. These run strictly off of the 5 volt. They do not over task the power supply and you can completely remove the 100 volt fuse. $195 but they look great. You really can not tell the difference. I personally know Brent Davis the designer of these displays. Great support and great product.

I had a chance to look at the site a few days ago. While my displays are now working pretty good again, your suggestion certainly looks like a viable alternative should I have one of those rare chips go bad.
Thanks again for the tip. Ken

 

[spalmer]

I had a chance to look at the site a few days ago. While my displays are now working pretty good again, your suggestion certainly looks like a viable alternative should I have one of those rare chips go bad.
Thanks again for the tip. Ken

Anytime. This is a picture of what mine looked like after the upgrade.

Had to show off. The second to are for Firepower Designer Steve Ritchie playing my machine at the Texas Pinball Festival this year.

 

[kdkal]

They do look darn good. Can't tell from the pic that they aren't the originals. You're game looks like it's in good shape as well.

Thanks again. Ken