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(Topic ID: 228068)

Bally -35 boot issues: LED locked on


By Brewchap

1 year ago



Topic Stats

  • 42 posts
  • 5 Pinsiders participating
  • Latest reply 1 year ago by zacaj
  • Topic is favorited by 1 Pinsider

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#1 1 year ago

I have a pulled MPU -35 that I am wanting to repair. I have tried to work on this myself using pinwiki once before. I have replaced all sockets and have a set of new burned ROMs. The board has also be jumpered to use these new ROMS. Also to note that this board had no battery corrosion what so ever on it. But the LED still stay locked on. I have also tested the CPU and PIA chips to make sure that they are good with another board.
What I would like to do is start from scratch, but I'm not sure where to start.

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#2 1 year ago
Quoted from Brewchap:

I have a pulled MPU -35 that I am wanting to repair. I have tried to work on this myself using pinwiki once before. I have replaced all sockets and have a set of new burned ROMs. The board has also be jumpered to use these new ROMS. Also to note that this board had no battery corrosion what so ever on it. But the LED still stay locked on. I have also tested the CPU and PIA chips to make sure that they are good with another board.
What I would like to do is start from scratch, but I'm not sure where to start.
[quoted image][quoted image][quoted image]

Take everything out except the roms, cpu, and led pia, then use a logic probe to check if all the inputs to the pia are functioning.
Could also be a bad clock for the cpu

#3 1 year ago

Do you ROMs match the jumpers on the board?

#4 1 year ago
Quoted from zacaj:

Take everything out except the roms, cpu, and led pia, then use a logic probe to check if all the inputs to the pia are functioning.
Could also be a bad clock for the cpu

I'm not sure looking at this print which is the input. Also am I looking for high or low signal or pulsing?

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#5 1 year ago

LED is on U11. Check everything on the left side. I would expect everything except the bottom 3 to have activity. (and maybe 37+38)

#6 1 year ago
Quoted from eh97ac:

Do you ROMs match the jumpers on the board?

Yes, I had the same problem with the original chip before the legs broke off

#7 1 year ago
Quoted from zacaj:

LED is on U11. Check everything on the left side. I would expect everything except the bottom 3 to have activity. (and maybe 37+38)

U11 Gotcha. I have no activity at all on any pin.

#8 1 year ago
Quoted from Brewchap:

U11 Gotcha. I have no activity at all on any pin.

Alright, back to the CPU checking activity. You should see movement on 3 and 37 from the clock (coming in from U15), or else the CPU won't run. If it's running you should see activity on the Address and Data lines

#9 1 year ago
Quoted from zacaj:

Alright, back to the CPU checking activity. You should see movement on 3 and 37 from the clock (coming in from U15), or else the CPU won't run. If it's running you should see activity on the Address and Data lines

There is nothing on 3 and 37 on the CPU.

#10 1 year ago

The jumpers look suspect and there is a wire jumper on the back of the board. I'm guessing some bad traces and soldering mistakes too.

#11 1 year ago
Quoted from Brewchap:

There is nothing on 3 and 37 on the CPU.

#12 1 year ago

Do you have any other working MPUs you could compare with? The clock signals are fragile enough that sometimes just reading them with a logic probe will mess them up, but usually it's fine. If the clock circuit isn't sending the proper signals into pins 3+37 of U9 then the CPU will never start. Probably U15 or U16 is bad, but they're both hard to come by

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#13 1 year ago

Looks like GPE has U15 and U16 in stock.

Here is my reading if this helps.

U15
pin 7 low
pin 8 high
pin 9 pulsing
pin 10 pulsing
pin 11 high
pin 12 pulsing
pin 13 pulsing
pin 14 high

U16
pin 1 nothing
pin 2 nothing
pin 3 high
pin 7 pulsing
pin 8 low
pin 9 pulsing
pin 10 pulsing
pin 11 high
pin 12 pulsing
pin 13 high
pin 14 nothing
pin 15 nothing

I can get another board on Monday, but it has corrosion damage on it and does not boot up. How far it boots I don't know yet if it does.

#14 1 year ago

U15-8 should be the inverse of 9 and 10, so I think it's definitely part of your problem, unless something has shorted pin 8. Can also try reading pin 8 with the CPU removed to see if that changes anything.

#15 1 year ago

No change on pin 8 with CPU removed.

#16 1 year ago

This board don't boot. I pulled the CPU and PIA's. LED dont even light up. Think that I'll pull U15 and try that on my other board.

No. Wash the junk off too see just how bad it really is.....

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#17 1 year ago

ok I changed U15 and now have pulsing on U15 pin 8 and on the CPU pin 3 and 37. Still have a solid LED light with all chips in.

#18 1 year ago
Quoted from Brewchap:

ok I changed U15 and now have pulsing on U15 pin 8 and on the CPU pin 3 and 37. Still have a solid LED light with all chips in.

OK cool. Now go back to checking the pia inputs

#19 1 year ago

Have you tried jumping pins 39-40 of u9 to see if you're not getting 5v stable quick enough? This is my bible:

http://techniek.flipperwinkel.nl/ballyss/rep/index2.htm#flash

#20 1 year ago

U11

36 pulsing
35 pulsing
22 pulsing
24 pulsing
23 pulsing
33 pulsing
32 pulsing
31 pulsing
30 pulsing
29 pulsing
28 pulsing
27 pulsing
26 pulsing
38 high
37 high
25 pulsing
21 pulsing
34 high
20 high
1 low

#21 1 year ago

U10

36 high
35 pulsing
22 pulsing
24 pulsing
23 pulsing
33 High
32 pulsing
31 low
30 pulsing
29 pulsing
28 pulsing
27 pulsing
26 pulsing
38 high
37 high
25 pulsing
21 pulsing
34 high
20 low
1 low

#22 1 year ago

So, CPU is now running and sending commands to the other chips, but the PIA isn't getting the specific command it needs to turn off the LED... Is this with just the ROMs, U11, and U9, or do you still have other chips installed? If not, I'd suspect the rom jumpering first of all (what rom types are you using?), otherwise something must be messing with the address/data lines..

#23 1 year ago

Just the ROMs, U11, and U9. Ill inspect the ROM jumpering again. The chip is a M2732A-2f1

#24 1 year ago

E4-13a, 7-8, 10-11, 12-GND, 16a-29, 31-32, 33-35 ( E13-15 Jumper CUTS)

#25 1 year ago

I dont think that I did the jumper cuts...

#26 1 year ago

It looks like E13-15 aren't jumpered to begin with in your original picture? What's that one wire on the back?

#27 1 year ago

The wire on the back is a jumper on a trace that I messed up on when I was replacing the socket. I pulled the socket out along with the trace. OUCH!

#28 1 year ago
Quoted from zacaj:

It looks like E13-15 aren't jumpered to begin with in your original picture?

correct

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#29 1 year ago

Jumpers are correct.

#30 1 year ago

I guess you should check the pins on the other chips then. Roms should have activity on 1-11, 13-19, 22,22. Low on 12, high on 24.

CPU should on all the A and D lines, as well as 34 and 5

#31 1 year ago
Quoted from zacaj:

I guess you should check the pins on the other chips then. Roms should have activity on 1-11, 13-19, 22,22. Low on 12, high on 24.
CPU should on all the A and D lines, as well as 34 and 5

You got 22 listed twice...

#32 1 year ago
Quoted from zacaj:

I guess you should check the pins on the other chips then. Roms should have activity on 1-11, 13-19, 22,22. Low on 12, high on 24.
CPU should on all the A and D lines, as well as 34 and 5

U6 tested correct while, U2 all tested correct but 18, which was low.

#33 1 year ago

CPU

A0/9 High and low on
A1/10 Pulsing
A2/11 Pulsing
A3/12 Pulsing
A4/13 High and low on
A5/14 Pulsing
A6/15 Pulsing
A7/16 Pulsing
A8/17 Pulsing
A9/18 Pulsing
A10/19 Pulsing
A11/20 Pulsing
A12/22 Pulsing
A13/23 Pulsing
A14/24 Pulsing

D0/33 Pulsing
D1/32 Low
D2/31 Pulsing
D3/30 Pulsing
D4/29 Pulsing
D5/28 Pulsing
D6/27 Pulsing
D7/26 Pulsing

#34 1 year ago

This is with chips U2 U6 U9 and U11 installed

#35 1 year ago
Quoted from Brewchap:

You got 22 listed twice...

Oops. Should be 22, 23.

Quoted from Brewchap:

U6 tested correct while, U2 all tested correct but 18, which was low.

With your specific jumpering (E12 - GND) that's correct.

Quoted from Brewchap:

A0/9 High and low on

what do you mean by "high and low on"?

This seems weird. This pin on U9 should be connected directly to the D1 line on the roms (pin 10) and PIA (pin 32), both of which you said had activity. Do you have good continuity between all of them? Maybe a bad socket or trace somewhere...

#36 1 year ago
Quoted from zacaj:

This seems weird. This pin on U9 should be connected directly to the D1 line on the roms (pin 10) and PIA (pin 32), both of which you said had activity. Do you have good continuity between all of them? Maybe a bad socket or trace somewhere...

Yes I have good continuity between all of them

Quoted from zacaj:

what do you mean by "high and low on"?

That both lights are on when testing that pin

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#37 1 year ago
Quoted from zacaj:

This seems weird. This pin on U9 should be connected directly to the D1 line on the roms (pin 10) and PIA (pin 32), both of which you said had activity. Do you have good continuity between all of them? Maybe a bad socket or trace somewhere...

This has me confused. I have gone back to double check the readings and they are not pulsing anymore. The continuity is good as I have checked that over and over again.
I'll keep looking.

#38 1 year ago
Quoted from Brewchap:

This has me confused. I have gone back to double check the readings and they are not pulsing anymore. The continuity is good as I have checked that over and over again.
I'll keep looking.

It should be pulsing at all 4 places. If it's not you might have a short somewhere or something. I even have one board with a problem like this where somewhere along the pcb the trace is actually cracked, so if you flex it it'll read different :/

#39 1 year ago

Which pin from U15 will the pulsing come from?

#40 1 year ago
Quoted from Brewchap:

Which pin from U15 will the pulsing come from?

Not from U15. All the Data line should be pulsing pretty much constantly. Different chips drive it at different times.

#41 1 year ago

Oh crap! Could a memory chip have anything to do with it? Some have data lines. Well U1, 7, and 8 does....

I maybe off on my thinking, but what is the best way of tracking down the lack of pulsing?

#42 1 year ago
Quoted from Brewchap:

Oh crap! Could a memory chip have anything to do with it? Some have data lines. Well U1, 7, and 8 does....
I maybe off on my thinking, but what is the best way of tracking down the lack of pulsing?

Anything on the data line could cause it. Ram, rom, pia, etc. Or stray solder.

You could try taking out all the chips, and measuring resistance from each Data like to ground, see if this one has a different reading. If so, you'd know it's not one of the socketed chips.

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