(Topic ID: 153986)

Gottlieb system 80 - Rottendog MPU - Reset light stays lit?

By amxfc3s

8 years ago


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#1 8 years ago

I am working on a Caveman...When I turn it on, it appears to boot up but the reset light (LED2) on the MPU stays lit. I am not sure if this is normal? I am not using the factory reset board, is there a mod or something I need to do to bypass it? The game will not coin up or go into test mode and I believe this is why.

Pinwiki says "Along with adding the reset board, Gottlieb® added a 3.0Kohm resistor across pins 7 and 11 of the reset board connection at MPU connector TC1. If not using the reset board, it's advised to add this resistor to the back of the board, as shown at right. This resistor pulls the read/write line to high when not pulled down by the 6502."

Is that what I need to do? I am hesitant to start modifying my brand new MPU. Any help would be appreciated. Thanks.

#2 8 years ago

Perhaps contacting Rottendog would be the thing to do and ask them about that issue? I don't know of anyone here that specializes in that board (or mods for it that could void the warrantee and damage it).

Steve
System 80, not just a job, it's an adventure

#3 8 years ago
Quoted from blownfuse:

Perhaps contacting Rottendog would be the thing to do and ask them about that issue? I don't know of anyone here that specializes in that board (or mods for it that could void the warrantee).
Steve
System 80, not just a job, it's an adventure

I sent them an email, figured I won't hear back until monday. Will post here with what they say so others will have the info. Was hoping someone might have already went through this.

#4 8 years ago

The 3K resistor added between pins 7 & 11 of TC1 adds a bit of extra current drive to the R/W line. Most CPU boards work fine without it...some refuse to work at all without it. But this refers to genuine Gottlieb boards. If Jims board is a direct copy of the Gottlieb CPU board then it might also need this resistor.

The voltage may be low to the CPU board which may be holding it reset. Could be power supply, could be a cable. To rule out the power supply, have you actually measured the DC voltage 'at the CPU board'? And have you repinned any connectors, particularly the one between the power supply and the CPU board?

#5 8 years ago
Quoted from G-P-E:

The 3K resistor added between pins 7 & 11 of TC1 adds a bit of extra current drive to the R/W line. Most CPU boards work fine without it...some refuse to work at all without it. But this refers to genuine Gottlieb boards. If Jims board is a direct copy of the Gottlieb CPU board then it might also need this resistor.
The voltage may be low to the CPU board which may be holding it reset. Could be power supply, could be a cable. To rule out the power supply, have you actually measured the DC voltage 'at the CPU board'? And have you repinned any connectors, particularly the one between the power supply and the CPU board?

I repinned the connectors in the head and rebuilt the power supply. The power supply to mpu connection is all brand new wire, pins, and connectors (that I ordered from you ) I am getting 5.05v coming into the mpu.

#6 8 years ago

here is a youtube video of me probing pins 7 and 11 of connector J10 (the only empty connector on the mpu, i guess its the same as TC1 on the OEM board)?

#7 8 years ago

I'm assuming pin 7 pulsing means +5V (not sure that specific logic probe). Definitely sounds like pin 11 is pulsing -- as it should be. I believe you're barking up the wrong tree with this one.

#8 8 years ago

I guess i'll wait and see what rottendog says...the probe is a Elenco Electronics LP-560, set to TTL (not CMOS). I should also mention the game has not worked since I bought it. The original MPU was completely dead. The obvious issue to me is the solid reset light on the MPU but I am open to other suggestions.

#9 8 years ago

I think the reset light is only shows that the reset line is high (which it should be.) Much like GPE's system80 tester shows this. It just indicates that the power on reset circuit is working. That's my understanding of it anyway.

On the rottendog sys80 MPU i've had chip socket problems where they were corroded. I've had to change those sockets on one MPU board i have. (it was a brand new board too, that i didn't put in a game for like two years.) I mentioned to Jim that i thought he had a bad batch of chip sockets. The 40 pin sockets were the issue on my board. Pull the chips and look at the pins (it's easy to see.) Mine were all gray, not shiny. Board didn't work consistently until i changed the offending sockets.

#10 8 years ago

I'll check the sockets, and reseat the chips in a little bit and report back.

#11 8 years ago

I reseated the chips and it now goes into attract mode. It's going into test mode and will coin up now. When I start a game the outhole kicker isn't kicking the ball into the shooter Lane. I'm going to replace the sockets and see what happens. It's almost working!

#12 8 years ago

woaa! Before you go replacing sockets, when in test mode do all of the solenoids fire? You could have a playfield problem at this point. Is there power to the coil -- you will have to remove the apron.

Perhaps there is a switch problem, do all of the trough switches register in switch test?

#13 8 years ago
Quoted from minnesota13:

woaa! Before you go replacing sockets, when in test mode do all of the solenoids fire? You could have a playfield problem at this point. Is there power to the coil -- you will have to remove the apron.
Perhaps there is a switch problem, do all of the trough switches register in switch test?

i'm going to go through the tests tonight, didnt have time to mess with it yesterday. the first time i turned it on, the outhole kicker (i think that's what it is called) fired, the second and third times, it did not. i know the switch is making contact. will mess with it again later this evening.

#14 8 years ago

Well I got it working...kinda haha. There are some playfield issues I need to address. None of the pop bumpers or drop target switches are working. I can tell someone before me was tampering with the pop bumper boards so I will rebuild them (I was planning on doing it anyway). One of the top ball shooter switches isn't working. I will need to look at the manual a bit to figure out what else I need to look at because the switches themselves check out fine. I cant figure out how to get the switch test to work in self test mode. The solenoid, sound, and switch test are all combined in the same step. I havent been able to let it just sit there, while i press a switch, and it tells the switch number. At least that's how my other (non system 80) games are.

#15 8 years ago

ive got a new rottendog driver board, and three pop bumper boards coming thursday...will mess with it more once those are installed.

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