Gold Wings - displays not working

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jasonm
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Location: Waukesha, WI
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Gold Wings - displays not working

Post by jasonm » Mon Mar 13, 2017 12:39 pm

Picked up a Gold Wings over the weekend. The machine is fully working except the displays don't come up. Checked the fuse in the bottom and that tests fine, both in and outside the holder. Took the display board off the speaker panel and did a visual inspection on them, they appear fine and not broken/degassed. Re-seated all the connectors going to them on the harness in the head. Still, nothing is coming up on them. Anything else to check that might be obvious?

When I picked it up, the guy did say they were working when he powered it up the day or two before; just that machine itself wouldn't start. Turned out to be bad wiring on the coin door. After a quick solder job it starts up and plays fine.
u2sean
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Re: Gold Wings - displays not working

Post by u2sean » Tue Mar 21, 2017 8:40 am

From Clay's guide:

System 80b Displays
The displays used on sys80b are again the Futaba displays, but they are alphanumeric. Mark posted this info on the displays, and I largely cut-and-pasted (and corrected) this info.
Sys80b Connecttor A4J1, display board:
Pin 1 = 6.2 vac feed (Display Filament)
Pin 2 = 6.2 vac return
Pin 3 = 32 vac feed (This gets rectified into -45VDC and -15VDC)
Pin 4 = 32 vac return
Pin 6 = Reset (Reset signal from Control Board A1J2 Pin 24). The reset signal
also continues to the sound board.
Pin 7 = +5 vdc
Pins 9,10 = LD1,LD2
Pins 11-18 = Data0-7
Pin 19 = Ground

On A4J1 pin 3,4 power comes in as 32 volts AC and goes to four CR1-CR4 1N4004 diodes, rectifying the power to DC. Diode VR1 (1n4737a) is used to get -45 volts DC, and VR2 (1N4744a) is used to get -15 volts DC. Also be aware that R2 (10k) and R1 (1k, 2 watts) should be checked as these dissipate some heat in the voltage
rectifying.

On the display board, also check resistors R3 (22k), R4 (10k), and R5 (3k). Display board chips Z1,Z2 are 7417 hex buffers and usually don't go bad. The same basic signal should be seen on the input and output of these two chips.

The voltages and signals on the display board can also be tested on the U1,U2,U3 chips. Also note that Q1 (2n3906) should be tested (power off) with a DMM set to diode function. With the power on, the reset line should go HIGH immediately after power-on (the signal starts low, but the CPU board triggers it high 50ms after bootup if all is working). This is the same reset signal seen at the CPU board chips U4-U6 pin 34 (RIOT).

The reset signal leaves the CPU board U5 pin 17 RIOT (Display Control chip) and goes to Z17 pin 1 (7404, an inverter). It then leaves Z17 pin 2 (as an inverted signal) and goes to CPU connector A1J2 Pin 24, and ultimately to the display and sound board.

Sys80b Display Board U1,U2 (digit drivers 10939).
Note this is not an easy chip to find, but usually it doesn't go bad:
Pins 1,38 = clock
Pin 2 = SOP
Pin 3 = SIP
Pins 6-13 = data DB0-DB7
Pins 15-34 = data D40-D21
Pin 35 = -45 vdc
Pin 36 = +5 vdc
Pin 37,39 = -15 vdc
Pin 40 = data-load

Sys80b Display Board U3 (segment driver 10941).
Note this is not an easy chip to find, but usually it doesn't go bad:
Pin 1 = -15 vdc
Pin 2 = +5 vdc
Pins 6-15 = segments n,m,l,k,j,i,h,g,f,e
Pin 16 = -45 vdc
Pin 17 = d segment
Pins 19,20 = segment c,b
Pin 22 = segment a
Pin 23 = clock
Pin 24 = data-load
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