I just finished a Bally -17 board. It had a lot of corrosion but all went well. (Note to Quench – the rare Eight Ball ROMs you asked for photos of – they work fine). With my confidence up I thought I’d try a really sick Bally -35 board that I had laying about. It has a lot of corrosion and someone worked on it before – jumper wires everywhere. No ROMs, No CPU, only one PIA, and a corroded 5101. Very sad.

First I installed a new CPU and tried testing with Leon’s test ROM. I had U9 activity on all pins except pin 23 (A13). What is A13 for? It looks to me the only place it goes is to J5 – pin 9.

It looks like the board has been modified for 2732 EPROMs so I installed new EPROMs at U2 and U6. At this point I only have U2, U6, U9, and U11. When I powered up the board I didn’t get a flicker – I got one flash and the LED went off. I tried several times and got the same results. Thinking the flicker was just weak and not showing I installed U7. Sure enough I got (no flicker) one flash – pause – then another flash. Then I installed U8. I got flash – pause – then two flashes. The only IC left was U10. So I installed a new PIA at U10 and got nothing. No flicker and no flashes. I removed the U10 and got the 3 flashes back. I tried several PIAs and get the same results. For some reason whenever U10 is installed it kills the boot up.

I removed the U10 socket and don’t see anything out of place. Anyone know why that happens?

Thanks

Bob

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I'm pretty sure it's a weak LED. I haven't changed it yet. I've had that happen before on another game - no flicker but it flashes and boots.

Yes.

I never tried that with U10 installed but now the socket is out and I'm working on replacing it.

I programmed Flash Gordon EPROMs. No real reason I chose them.

U10 socket is removed - I haven't replaced it yet (remember I'm old and slow). Could I test it just probing the solder pads? What should I expect?

I'll check it out when I get back down to the shop.

I looked for a short (but not with a DMM) and didn't see anything suspicious. The socket was original (and a junk single leaf style).

I"m not positive but I think I tried that. The U11 PIA came with the board so like everything else on this board it was suspect.

Can someone explain the long white jumper wire on the back of the board? It seems to be going from U9 pin 24 to E29. I think the connection is correct but the U9 socket seems to be original (and junk) and the pin 24 solder pad looks to be OK - unlike pin 23. I'm guessing there might be a bad trace somewhere in that circuit. I'll check it out closely when I replace the U9 socket.

Thanks

Bob

I looked at that stuff between U10 and U11. I couldn't tell what it was. I brushed it off with a brass brush and it came right off.

I checked the continuity from U14 pin 3 to the via. It was good. I then checked from U14 to U9 pin 24. It was good also. Then I disconnected the wire at E29. Now I don't have continuity to E29. Not from U14 or U9. I haven't looked any closer but should there be a trace from U9 pin 24 to E29?

I'll check on that trace tomorrow. I wonder why he didn't just jumper from U14 to E29? Would have been a shorter route. I think I can see the trace in this photo.

I got the U10 socket ready to install. My best removal job yet. Didn't loose a pad. You guys are teaching me well.

I look this board over and wonder why I'm working on it. It's in such bad shape. I'm sure we'll get it going again but I wouldn't trust it in a game and I certainly wouldn't sell it to anyone. I must be really bored.

Thanks

Bob

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I replaced the U10 socket and the LED. I installed a new PIA and got solid on. No flicker but the LED is very bright now.

After I got the solid on I removed the U10 PIA and tried again. Same as before – flash – pause – flash – flash (but still no flicker). I don’t think this thing flickers at all. I tried another PIA and get the same results – solid on. Occasionally I get a flash then off.

Should I be chasing the missing flicker or looking for a problem with the U10? Could they both be related?

If it’s not booting why am I getting the 3 flashes?

Thanks

Bob

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Finally got some shop time today.

I looked for a short and didn't see anything. Then I used my analog meter to sweep across all the address pins. It did show some resistance on almost all pins. Then I tested a good board and pretty much got the same results.

Nothing - LED stays on. Voltage at U9 pin 40 = 5.4 VDC.

I get high/low with pulse. But there is a slight hesitation before the pulse begins. I get the same results on 22, 23 and 24. I also tested U11 and got the same.

I'll pull U10 and test again after dinner.

Bob

I hope I can explain this. I removed U10 - power on - long solid on - pause - then 2 flashes. Same as before. Nothing probed.

I probed on U10 pin 22 then powered on. LED shows solid on and probe shows high / low / pulse. But the LED stayed solid on.

Next I powered on (same as step one) after the 3 flashes I probed pin 22 = low - no pulse. On pin 23 and 24 I got high - no pulse.

Looks like touching the probe on 22, 23, 24 keeps it from booting. And the LED remains on even after I remove the probe.

This really has me stumped.

Thanks

Bob

Both checked OK

I also have continuity from U10 - P23 to U11 - p23 and to U17 - P6.

And from U17 P13 to U18 P11.

I have no continuity from any pin on U18 to U10 P23.

Both U17 and U19 have several pads missing on the solder side. I'll check into that closer and take some photos.

Bob

I took a bunch of photos (for your viewing pleasure). Believe it or not these photos help me see and remember where suspect places are.

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U14:

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U19:

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And U17:

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I wish I was getting paid by the hour. This would be a 500.00 board.

Thanks

Bob

Besides what I highlighted - that was my plan. If you don't hear from me for a few days, I'll be behind my DMM.

Unless I can find another board that needs me.

Thanks

Bob