(Topic ID: 243572)

Harlem Globetrotters- 1 flash on MPU no boot up


By pindude80

6 months ago



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  • Latest reply 6 months ago by pindude80
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#1 6 months ago

As some of you may have seen in another thread I have I am working on my control lights. I was getting ready to pull my lamp board to replace the header pins but I thought before I do that I wanted to see how many bad sockets I was looking at. I took a jumper wire from the ground braid and touched against the metal tang where the insulated wire attaches on a few of the lights. On two different lights that were right next to each other when I did this the speaker made a buzzing sound then I heard a noise which I think sounded like a if you dropped a coin in a coin slot then no control lights. I turned the game off, checked all of my fuses, they were all good, went to boot the game and I only get one flash.

Any ideas on what I screwed up?

#2 6 months ago

Morning Bump! I took off work today to get some stuff done around the house, work on the game, and I end up screwing it up the night before.

Anyone know what I need to check?

#3 6 months ago

http://www.oocities.org/timessquare/arcade/7800/flash.html

Looks like the RAM might be bad, good chance it is just the socket.

#4 6 months ago

so you think it may have just shorted out the socket? Before replacing would I just check it by doing a continuity test from the legs of the ram to where they run to on the backside of the board?

#5 6 months ago

Can you clarify one flash LED? Does the LED just flicker the moment you power it on, or is it a flicker, half second off then flash on for half a second and then it turns off and stays off?

Is it a factory Bally MPU board or aftermarket MPU board?

#6 6 months ago
Quoted from Quench:

Can you clarify one flash LED? Does the LED just flicker the moment you power it on, or is it a flicker, half second off then flash on for half a second and then it turns off and stays off?
Is it a factory Bally MPU board or aftermarket MPU board?

I get an initial flicker right at power up then one flash then it goes off. It's a factory Bally 35 board.

#7 6 months ago
Quoted from pindude80:

I get an initial flicker right at power up then one flash then it goes off. It's a factory Bally 35 board.

Ok, the aftermarket boards behave slightly differently in this scenario which is why I asked.

As BarryJ mentioned it's pointing to a problem around the 6810 RAM chip at U7 on the MPU board.
Do you have any other early Bally/Stern machines?

Can you post a real clear high res picture of the MPU board and of the RAM chip at U7?
Also a picture of exactly where you jumpered your ground wire that caused the hiccup so we can try to build some sense of what's gone wrong.

#8 6 months ago

No problem on asking which board it has in it.

From the little I read I also saw the 6810 RAM is suspect but I don't know anything about it or how to check it.

Yes I do have other games- Trident, Meteor, EBD

Check out the pictures. The one that I have my fingers pointing to the sockets are the ones I was testing. I was just touching the one end to the bulb tang where the insulated wire attaches and the other end was clipped to the ground braid down in the cabinet. I also have another picture without my fingers in the way, in that picture it's the middle 2 sockets on the left.

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#9 6 months ago

Grounding the metal end tabs of those lamps you're pointing to shouldn't have caused any issues.
Is there any possibility your ground wire accidentally touched one of those three bare twisted wire connectors coming off the flipper switch stack? I'd suggest wrapping those twists in electrical tape for now or deal with them properly by soldering and heatshrink insulating them.

The MPU board has very little/barely any battery corrosion so you're lucky in that respect.
It's a pity someone has soldered in the battery backed 5101 RAM chip at U8. Makes it harder for you to put a NVRAM chip down the track.

Anyway, with the machine off, carefully pull out the 6810 RAM chip at U7 and reinstall it and see what happens.

Note your CPU at U9 is an AMI brand chip and they have a higher than normal failure rate.

#10 6 months ago
Quoted from Quench:

Grounding the metal end tabs of those lamps you're pointing to shouldn't have caused any issues.
Is there any possibility your ground wire accidentally touched one of those three bare twisted wire connectors coming off the flipper switch stack? I'd suggest wrapping those twists in electrical tape for now or deal with them properly by soldering and heatshrink insulating them.
The MPU board has very little/barely any battery corrosion so you're lucky in that respect.
It's a pity someone has soldered in the battery backed 5101 RAM chip at U8. Makes it harder for you to put a NVRAM chip down the track.
Anyway, with the machine off, carefully pull out the 6810 RAM chip at U7 and reinstall it and see what happens.
Note your CPU at U9 is an AMI brand chip and they have a higher than normal failure rate.

Was thinking the same about that switch stack. Man, that's ugly and just screaming "I'm gonna cause you trouble...I'm right here waiting!"

Also, if he has a desolder gun and a socket, it shouldn't be an issue to get the chip at U8 out and solder in a new socket.

#11 6 months ago
Quoted from Quench:

Grounding the metal end tabs of those lamps you're pointing to shouldn't have caused any issues.
Is there any possibility your ground wire accidentally touched one of those three bare twisted wire connectors coming off the flipper switch stack? I'd suggest wrapping those twists in electrical tape for now or deal with them properly by soldering and heatshrink insulating them.
The MPU board has very little/barely any battery corrosion so you're lucky in that respect.
It's a pity someone has soldered in the battery backed 5101 RAM chip at U8. Makes it harder for you to put a NVRAM chip down the track.
Anyway, with the machine off, carefully pull out the 6810 RAM chip at U7 and reinstall it and see what happens.
Note your CPU at U9 is an AMI brand chip and they have a higher than normal failure rate.

You know, I saw those same wires after and thought the same thing that my lead could have touched one. It's the work of some hack in the past that I planned on soldering and shrink tubing eventually but will probably do as you suggested and wrap in electrical tape for now.

I know, it sucks about the 5101 RAM and that's why we ran the remote battery instead of doing the NVRAM but as Panda mentioned I do have a desoldering machine and may end up adding the NVRAM at some point. I carefully pulled the RAM chip from U7, carefully put back in but am getting the same thing- 1 quick LED flicker, 1 longer flash, it goes out and nothing happens.

#12 6 months ago
Quoted from pindude80:

I carefully pulled the RAM chip from U7, carefully put back in but am getting the same thing- 1 quick LED flicker, 1 longer flash, it goes out and nothing happens.

Ok, pull that U7 RAM chip out and carefully install it in one of your other games MPU board and see if the fault follows the RAM chip. If it doesn't carefully swap the CPU at U9 into that other game aswell.

#13 6 months ago

I installed the RAM chip in Eight Ball Deluxe and that machine booted up. I then installed the CPU from u9 in Eight Ball Deluxe but it would not boot. I tried to boot it several times and it didn't act exactly as it did in Harlem Globetrotters to where I would only get the flicker and one flash. A couple times it did that but a couple other times it would flash a few more times. I think I saw it go up to 6 flashes but once again the game never booted and there were a few little flickers between the longer flashes.

#14 6 months ago
Quoted from pindude80:

I installed the RAM chip in Eight Ball Deluxe and that machine booted up. I then installed the CPU from u9 in Eight Ball Deluxe but it would not boot. I tried to boot it several times and it didn't act exactly as it did in Harlem Globetrotters to where I would only get the flicker and one flash. A couple times it did that but a couple other times it would flash a few more times. I think I saw it go up to 6 flashes but once again the game never booted and there were a few little flickers between the longer flashes.

Have you tried the working U9 chip from EBD to Globetrotters to see if it boots Globetrotters boots?

#15 6 months ago

Not yet, figured that was the next step but wanted to wait to hear back from you guys. Should I go ahead and swap it in?

#16 6 months ago

I installed the U9 chip out of eight ball Deluxe. I powered up the game and the LED kept flashing without booting the game. I do have the lamp board out of the game so I am hoping that is the cause of this.

#17 6 months ago
Quoted from pindude80:

I installed the U9 chip out of eight ball Deluxe. I powered up the game and the LED kept flashing without booting the game. I do have the lamp board out of the game so I am hoping that is the cause of this.

The disconnected lamp board won't be causing this. You are now potentially looking at more MPU board problems to resolve. U10 and U11 are both the same 6821 chips. Swap them around and see if the behavior changes..

What's the deal with the skinny grey jumper wires on the MPU board? Are they bare wire or grey insulated wire? If bare, are they touching anything they shouldn't be?

Are you confident your old U9 CPU chip is faulty? i.e. if you put it back in Harlem Globetrotters On Tour does it return to single LED flash?

#18 6 months ago

I figured out why it wouldn't boot, you guys are going to crack up. I didn't have the U7 chip in it! I popped you u7 and it fired right up! Thanks for all of the help today and getting me up and running again!

It looks like my time and hard work on the lamp board is starting to pay off. This is the most control lights I've seen on since I've had it but still have about 14 out that I'll have to look into this weekend.

#19 6 months ago

Good to hear you sorted it. So in the end the 6800 CPU at U9 died.

#20 6 months ago
Quoted from Quench:

Good to hear you sorted it. So in the end the 6800 CPU at U9 died.

Yep, seems the AMI U9 chip bit the dust. I will have to look around to see if I can find another one so I can get my EBD back up and going. Do you know if this chip is still made or will I have to find a used chip?

#21 6 months ago

I do this all of the time. I start a thread on a problem I'm stuck on, and then it turns out to be the easiest fix. Glad you got it resolved.

#22 6 months ago

Yeah I'm very glad it's up and going again or the wind would have really been taken out of my sails on getting this beater back to being a respectable game. It was an easy fix as far as parts and effort were concerned but I never would have known to swap the U9 chip without help from this thread.

#23 6 months ago
Quoted from pindude80:

Yep, seems the AMI U9 chip bit the dust. I will have to look around to see if I can find another one so I can get my EBD back up and going. Do you know if this chip is still made or will I have to find a used chip?

6800 CPUs went out of production years ago, but you can still find them:

Marcos:
https://www.marcospecialties.com/pinball-parts/6800

ebay (might be original markings):
ebay.com link » Nxp Semiconductor Mc6800p Mc6800p New No Box

ebay (looks like a China remark):
ebay.com link » Mc6800p Dip 40 8 Bitmicroprocessing Unit Mpu

#24 6 months ago

Ok. Thanks for posting the links! I might be able to find an original from someone in our local pinball group or I could get one from one of the links you posted. What do you think about the China remake? If you think it would be better to find an original or get the one from Marco I will do whatever you think is best.

#25 6 months ago
Quoted from pindude80:

What do you think about the China remake?

They're not remakes, they are remarks. i.e. old chips that have been "reconditioned" to look like new with the part numbers remarked (often with a bogus manufacture date). They then advertise them as "new and original"...

Personally I use them a lot and at just over a dollar each out of China in small bulk quantities I haven't had any problems with them. yet..

Maybe grab one from Marcos with some other spare pinball parts you'll likely to need.

#26 6 months ago

Ok, remarks, I get it, thought it was remake. I'll probably grab that one and the other from Marco next time I place an order with them.

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