Gottlieb Sys 80B Not booting up

James8902

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Hello all I purchased a non working Tag Team and Resoledred the ROM chip to a remote location off the Main CPR due to cracks in the solder. The game worked for about a month with no problems and the last week it stopped booting up. I am new to this hobby and I need some help. This is what I have come up with while th eboare is on the bench with 5.10vdc applied and it is pulling approximatly 1.11Amps.



U1 Pin 40 (RES) Low going high on power on. Remains high.
U4, U5, U6 pin 34 (RES) same as for U1.

Clock circuit

U1 Pin 37 (phase 1 in) ~ 833 Khz.
U1 Pin 38 5vdc?
Z3 Pin 11 Same as Pin 37 clock pulse
Z3 pin 10 Same
Z3 pin 13 same.
Z3 pin 12 same.
U4 pin 39 same.
U1 Pin 2 (RDY) +4.95 Vdc.
U1 Pin 4 (IRQ not) High signal not pulsing.

U1 address lines:
Pin 9 (AB0) no activity.
Pin 10 (AB1) no activity.
Pin 11 (AB2) ditto.
Pin 12 (AB3) ditto.
Pin 13 (AB4) ditto.
Pin 14 (AB5) ditto
Pin 15 (AB6) DC voltage with small square wave superimposed, same as pin 40 on U4, U5, U6 (which is A6 on those chips).
Pin 16 (AB7) similar to pin 9 - 14. 5 vdc
Pin 17 (AB8) CRO 5 vdc
Pin 18 (AB9) 5 vdc
Pin 19 (AB10) 5vdc
Pin 20 (AB11) 5 vdc
Pin 22 (AB12) 5vdc
Pin 23 (AB13) 5vdc

U1 Data bus lines:
Pin 33 (DB0) 5vdc
Pin 32- 26 (DB1-7) 5vdc

Switch matrix chips
Z13
Pin 1,2,4,5,9,10,12,13 +5v DC

Pin 3,6,8,11 Low

Z14
Pin 1,2,4,5,9,10,12,13 +5v DC

Pin 3,6,8,11 Low

Switch Matrix Strobes/Rows:
Z11
Pin 2,4,6,8,10,12 all low
Pin 1,3,5,9,11,13 all high

Z12
Pin 2,4 low
Pin 1,3 high

RIOT Chips Chip select:

U4
Pin 37 (CS2 not) Square wave approximately 5vdc
Pin 38 (CS1) low

U5
Pin 37 (CS2 not) 5vdc
Pin 38 (CS1) 0

U6
Pin 37 (CS2 not) 5vdc
Pin 38 (CS1) Low .

U4 Switch Matrix Strobes
Pin 24 -21, 19 - 17 (PB0 - PB6) All high
pin 20 (VCC) +5v DC.
pin 39 (phase 2 clock) ~833 Khz.
pin 25 (IRQ not) High no pulsing
pin 38 (CS1) nothing
pin 37 (CS2 not) high
pin 36 (RS not) high
pin 35 (R/Wnot) high
pin 34 (RES not) high.
pin 1 (VSS) gnd.

A0 - A6 (pins 7-2 and 40)
As per U1 no activity

D0 - D7 (pins 33 - 26)
As per U1 no activity

PA0 - PA7 (pins 8 - 15) all low.
PB0 - PB7 (pins 24-21, 19-16) all high.


Any ideals of what to check next. I am leaning to replacing the u4 riot chip but I am not sure. Any help Thank you
Jim
 
I aquired a robo war system 80b that would not boot. The problem with mine was cracked solder on the ground connector at the transformer. Might want to check that as well.
 
Hello all I purchased a non working Tag Team and Resoledred the ROM chip to a remote location off the Main CPR due to cracks in the solder. The game worked for about a month with no problems and the last week it stopped booting up. I am new to this hobby and I need some help. This is what I have come up with while th eboare is on the bench with 5.10vdc applied and it is pulling approximatly 1.11Amps.

...

U1 Pin 4 (IRQ not) High signal not pulsing.

...

Any ideals of what to check next. I am leaning to replacing the u4 riot chip but I am not sure. Any help Thank you
Jim

With IRQ high -- I wouldn't suspect U4 yet.

Sounds like the CPU is running in the weeds. First thing I would suspect is a problem with that U2/U3 EPROM adapter. Sounds like you may have missed reflowing a pin to that unreliable POS adapter.

Ed
 
I took off that Piggy back board and Ran wires to the Second Prom, The game was working very good for about a month or so. I checked the wires to the second prom and the connections are solid. I made one of the Larry hammer Generators (NOP) The board takes about 1.30 Amps now and the Address lines look Like they are High with slight activity around the 5 volt area. A few of them are low with slight activity around the 0 mark? Are the pulses suppose to drop down to 0 then backup to high? I am not really seeing any high and low pulses with this NOP? The board is on a test bench with clean power , good clock signal and I have a good scope. I am leaning to the changing the U1 micro processer 6502? Any ideas where to get one, I want to socket it too. Am I on the right track? Thank you for your help.

Jim
 
I took off that Piggy back board and Ran wires to the Second Prom, The game was working very good for about a month or so. I checked the wires to the second prom and the connections are solid. I made one of the Larry hammer Generators (NOP) The board takes about 1.30 Amps now and the Address lines look Like they are High with slight activity around the 5 volt area. A few of them are low with slight activity around the 0 mark? Are the pulses suppose to drop down to 0 then backup to high? I am not really seeing any high and low pulses with this NOP? The board is on a test bench with clean power , good clock signal and I have a good scope. I am leaning to the changing the U1 micro processer 6502? Any ideas where to get one, I want to socket it too. Am I on the right track? Thank you for your help.

Jim

Hard to tell where the fault is based on this.
Sounds like you need to borrow somebody's QuickScan80 test fixture...
know of anybody near you that has one?

-- Ed
 
No I do not know of anyone around the twin cities. I have ordered a new 6502 and three riot chips. I hope this will help. Can a person still buy a scan 80? I tried to purchase one and the website said they were out of stock.

Jim
 
No I do not know of anyone around the twin cities. I have ordered a new 6502 and three riot chips. I hope this will help. Can a person still buy a scan 80? I tried to purchase one and the website said they were out of stock.

Jim

The current single 7-segment digit version of QuickScan80 is at the end and won't be rebuilt. I'm currently in the process of redesigning them. Main difference being to increase the number of 7-Segment displays on the board. May be a few months before they're back.

Ed
 
Hello Ed

I am still working on my derelict board. I am seeing a pulse on the SO line where on a different board the pulse is not there. Pin 6 NMI is tied to Pin 38 SO with 5 vdc. The pulse is being generated in the SO. Am I on the right track? Also do you know where the 1n207 diode goes. have one board that it goes from pin 17 Anode of the TC1 board to the cathode pin 37 of the TC1 board. Diode cr1. Other note when I put my Prom 2 in the circuit it kill all the A/D's. Tried different prom no help? What do you think?

Thank you
Jim
 
Hello Ed

I am still working on my derelict board. I am seeing a pulse on the SO line where on a different board the pulse is not there. Pin 6 NMI is tied to Pin 38 SO with 5 vdc. The pulse is being generated in the SO. Am I on the right track? Also do you know where the 1n207 diode goes. have one board that it goes from pin 17 Anode of the TC1 board to the cathode pin 37 of the TC1 board. Diode cr1. Other note when I put my Prom 2 in the circuit it kill all the A/D's. Tried different prom no help? What do you think?

Thank you
Jim

Not sure what you are seeing with the SO line. Bot Non-Maskable Interrupt (NMI) and Set Overflow (SO) are inputs... there is no way a properly functioning part can set these - there's no output driver.

No clue on the 1N207... sounds like that board had a different connection to the watchdog board. With the cathode @ 17 and anode at pin 37 - ties clock to address A8 and pulls A8 low whenever clock is low. Definetly not something you would want to do.
There -is- a modification done to some TC1 plugs where they add a 3K ohm pullup resistor between pins 7 and 11. I have seen boards that refused to work without this resistor added.

Definitely something wrong with PROM2 - shouldn't kill all the lines. Blank PROM? Is enable to it permanently on?

Ed
 
I will check the Enable on Prom 2. I have noticed that when I put the board in my spring break machine or the Tag team machine the Game over relay is powered on in both games along with a few other relays? I will take the diode out of the circuit,the one that goes from the TCI plug. I can see the diode on the schematic but not where the Cathode goes. One game came with the diode and the other did not. The one with out, is the game that worked for months. I will let you know what happens , any idea why the game relay is power with the board in each of the games>

Thank you
Jim
 
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