Solid green led on -35 Bally mpu

[wozzer]

Hi,
Can anyone help? I have a solid green led on my Bally -35 mpu, when I
short pin 39 & 40 on U11 the board resets, but then if I switch it off
and switch it on again the led is then off although I still have my
12v ok and the playfield lights up but nothing happens until I short
pins 39 & 40 again then it resets ok with the led still off I might
add.
There is no corrosion on the board, I have swapped U11 and U9 for
working chips and they make no difference. I am unable to swap U6 as I
don't have another set of game proms. The game is an Elektra. I have
metered most of the reset circuit and it seems ok, has anyone come
across this before?

[firepower]

Post by wozzer
Hi,
Can anyone help? I have a solid green led on my Bally -35 mpu, when I
short pin 39 & 40 on U11 the board resets, but then if I switch it off
and switch it on again the led is then off although I still have my
12v ok and the playfield lights up but nothing happens until I short
pins 39 & 40 again then it resets ok with the led still off I might
add.
There is no corrosion on the board, I have swapped U11 and U9 for
working chips and they make no difference. I am unable to swap U6 as I
don't have another set of game proms. The game is an Elektra. I have
metered most of the reset circuit and it seems ok, has anyone come
across this before?

Swap CPU for a known good one?

[firepower]

Oh sorry, you said you swapped U11 and U9.

Must be the reset, not much to that circuit. I usually start by
replacing the 2n4403 transistor...

-Richard

Post by firepower

Post by wozzer
Hi,
Can anyone help? I have a solid green led on my Bally -35 mpu, when I
short pin 39& 40 on U11 the board resets, but then if I switch it off
and switch it on again the led is then off although I still have my
12v ok and the playfield lights up but nothing happens until I short
pins 39& 40 again then it resets ok with the led still off I might
add.
There is no corrosion on the board, I have swapped U11 and U9 for
working chips and they make no difference. I am unable to swap U6 as I
don't have another set of game proms. The game is an Elektra. I have
metered most of the reset circuit and it seems ok, has anyone come
across this before?

Swap CPU for a known good one?

[seymour.shabow]

Post by wozzer
Hi,
Can anyone help? I have a solid green led on my Bally -35 mpu, when I
short pin 39 & 40 on U11 the board resets, but then if I switch it off
and switch it on again the led is then off although I still have my
12v ok and the playfield lights up but nothing happens until I short
pins 39 & 40 again then it resets ok with the led still off I might
add.
There is no corrosion on the board, I have swapped U11 and U9 for
working chips and they make no difference. I am unable to swap U6 as I
don't have another set of game proms. The game is an Elektra. I have
metered most of the reset circuit and it seems ok, has anyone come
across this before?

Replace q1, q2, and q5. That should get the game booting. However, the
first thing the code does is turn off the LED (which is working, so
perhaps Q2 is ok).

The next thing it does it take a checksum of the roms, which it sounds
like it does NOT. so, possible rom issue. Either sockets, or the chips
themselves (is there any black crud on the chip legs?)

-scott CARGPB#29

[wozzer]

Post by wozzer
Hi,
Can anyone help? I have a solid green led on my Bally -35 mpu, when I
short pin 39 & 40 on U11 the board resets, but then if I switch it off
and switch it on again the led is then off although I still have my
12v ok and the playfield lights up but nothing happens until I short
pins 39 & 40 again then it resets ok with the led still off I might
add.
There is no corrosion on the board, I have swapped U11 and U9 for
working chips and they make no difference. I am unable to swap U6 as I
don't have another set of game proms. The game is an Elektra. I have
metered most of the reset circuit and it seems ok, has anyone come
across this before?

Replace q1, q2, and q5.  That should get the game booting.  However, the
first thing the code does is turn off the LED (which is working, so
perhaps Q2 is ok).
The next thing it does it take a checksum of the roms, which it sounds
like it does NOT.  so, possible rom issue.  Either sockets, or the chips
themselves (is there any black crud on the chip legs?)
-scott CARGPB#29

Ther is a bit of crap on the legs but not much, I have changed the
2n4403, is a bit of a pain this one, I will try cleaning all of the
crap off and changing the ic sockets on U11 & 9.

[WarpZoneArcade.com]

Post by wozzer
Hi,
Can anyone help? I have a solid green led on my Bally -35 mpu, when I
short pin 39 & 40 on U11 the board resets, but then if I switch it off
and switch it on again the led is then off although I still have my
12v ok and the playfield lights up but nothing happens until I short
pins 39 & 40 again then it resets ok with the led still off I might
add.

Are you sure you're not shorting pin 39 to 40 on U9 and not U11?

If you're saying that the game boots and plays when you short pin 39
to 40 on U9 then you have a reset problem. I would suggest installing
a Dallas DS1811. You can find instructions in Clay's guide
(pinrepair.com/bally).

Post by wozzer
There is no corrosion on the board, I have swapped U11 and U9 for
working chips and they make no difference. I am unable to swap U6 as I
don't have another set of game proms. The game is an Elektra. I have
metered most of the reset circuit and it seems ok, has anyone come
across this before?

It's pretty clearly a reset problem (IMO) so known good chips won't
help you because the ones on the board are good. Again, assuming a
manual reset makes it boot and play.

I sell a little daughter board that plugs into J5 and replaces the
EPROMs as well as adding a Dallas reset circuit. Here's an example.
The latest version includes reset:

http://warpzonearcade.com/?p=356

Send me an email if you're interested but you probably just need to
rebuild your reset section or replace it with a DS1811. Unless you
really do mean U11 in which case I'll have to rethink my answer ;)

[Raimo Saario]

Post by WarpZoneArcade.com

Post by wozzer
Hi,
Can anyone help? I have a solid green led on my Bally -35 mpu, when I
short pin 39 & 40 on U11 the board resets, but then if I switch it off
and switch it on again the led is then off although I still have my
12v ok and the playfield lights up but nothing happens until I short
pins 39 & 40 again then it resets ok with the led still off I might
add.

Are you sure you're not shorting pin 39 to 40 on U9 and not U11?
If you're saying that the game boots and plays when you short pin 39
to 40 on U9 then you have a reset problem. I would suggest installing
a Dallas DS1811. You can find instructions in Clay's guide
(pinrepair.com/bally).

Post by wozzer
There is no corrosion on the board, I have swapped U11 and U9 for
working chips and they make no difference. I am unable to swap U6 as I
don't have another set of game proms. The game is an Elektra. I have
metered most of the reset circuit and it seems ok, has anyone come
across this before?

It's pretty clearly a reset problem (IMO) so known good chips won't
help you because the ones on the board are good. Again, assuming a
manual reset makes it boot and play.
I sell a little daughter board that plugs into J5 and replaces the
EPROMs as well as adding a Dallas reset circuit. Here's an example.
http://warpzonearcade.com/?p=356
Send me an email if you're interested but you probably just need to
rebuild your reset section or replace it with a DS1811. Unless you
really do mean U11 in which case I'll have to rethink my answer ;)