Spy Hunter MCR Help (garbled screen)

TSB

Well-known member
Joined
Jan 14, 2016
Messages
2,541
Reaction score
916
Location
Alaska
Now that I've got the linear power supply to acceptable stability (https://forums.arcade-museum.com/showthread.php?t=409438), I've moved on to the MCR stack.

Here's what I've done so far:
- Replaced Caps
- Reflowed Headers
- Replaced Ribbon Cables
- Replaced Power Cable Connector/Pins at Linear Power Supply J4/J5, and Super CPU Board J1.

The image on the screen didn't change much afterwards. It was basically the same (pic1). Troubleshooting the MCR seemed to be the next step.


A close inspection of the board stack showed that
The Video Gen board:
- looks good - no mods or fixes.
The Super CPU board:
- A couple traces had been cut & jumper wires soldered in. Behind R159 & R160 on the solder side, and next to the Analog De/Multiplexor Chip 1G (MC14053B).
- Jumpers JW2, 11, 14, and 15 have been snipped, and both JW1 & JW13 have a resistor in its place.
The Super Sound I/O board:
- Caps C104 - C111 have been snipped, as has the SIP Resistor at RM3.
- LED 1-3 are missing (they don't appear to have been installed).

Are these common mods? Or are they something you'd find on a problematic board set?
I'd like to fill in those LEDs also, but I can't find specs on them.
 

Attachments

  • IMG_8938.JPG
    IMG_8938.JPG
    160.3 KB · Views: 65
  • IMG_3619.JPG
    IMG_3619.JPG
    397.8 KB · Views: 63
  • IMG_3620.JPG
    IMG_3620.JPG
    439.1 KB · Views: 55
  • IMG_3621.JPG
    IMG_3621.JPG
    377.9 KB · Views: 43
  • IMG_3622.JPG
    IMG_3622.JPG
    283.6 KB · Views: 44
Last edited:
can't access the boards to Spy Hunter/Tron at work right now for reference, but was your power supply battery damaged at all? typically the alkaline can go all the way into the plugs. so if the pins in the plugs are glazed over with alkaline, you'll lose enough voltage to the boards that the game won't run.

if you look in the PSU guide in my signature it shows how to measure voltage at chips, I would encourage doing this to see that +5 is getting there at all. otherwise the next step I would try replacing the CPU on the Super CPU board with a known good one.

lastly, it's very easy to bend the header pins for the ribbon cables between the boards. if one of them isn't even with the rest, you'll wind up pushing the pin backward and it won't go into the ribbon.

beyond that, the missing stuff on the SSIO shouldn't prevent the game from booting. you would in the very least if those parts were needed just not have sounds.
 
can't access the boards to Spy Hunter/Tron at work right now for reference, but was your power supply battery damaged at all? typically the alkaline can go all the way into the plugs. so if the pins in the plugs are glazed over with alkaline, you'll lose enough voltage to the boards that the game won't run.
They were glazed on the power supply side, but the plugs and pins have all been replaced on both ends.

lastly, it's very easy to bend the header pins for the ribbon cables between the boards. if one of them isn't even with the rest, you'll wind up pushing the pin backward and it won't go into the ribbon.
I double checked this. They all appear to be connected properly.

if you look in the PSU guide in my signature it shows how to measure voltage at chips, I would encourage doing this to see that +5 is getting there at all. otherwise the next step I would try replacing the CPU on the Super CPU board with a known good one.
I'll check that out. I got readings off of the Linear Power Supply instead of at the chips. I wish I had a known good CPU... I will probably have to cross that road eventually.

beyond that, the missing stuff on the SSIO shouldn't prevent the game from booting. you would in the very least if those parts were needed just not have sounds.
Glad it's not a big deal. It would be nice if I could find specs for the LEDs, though. I'd like to have access to the readout.
 
A close inspection of the board stack showed that
The Video Gen board:
- looks good - no mods or fixes.
The Super CPU board:
- A couple traces had been cut & jumper wires soldered in. Behind R159 & R160 on the solder side, and next to the Analog De/Multiplexor Chip 1G (MC14053B).
No idea what that' supposed to do -- those are just series termination for the high speed clock lines, but that hack looks like it's swapping the 10M and 20M signals.

- Jumpers JW2, 11, 14, and 15 have been snipped, and both JW1 & JW13 have a resistor in its place.
Those "resistors" are zero ohm jumpers. They're all populated by default then clipped for production.

Either 1 or 2 and either 13 or 14 should be in place. 11 should be clipped. 15 should be clipped if 13 is there instead of 14.

The Super Sound I/O board:
- Caps C104 - C111 have been snipped, as has the SIP Resistor at RM3.
- LED 1-3 are missing (they don't appear to have been installed).

The R/C network is missing since that bank of inputs comes from the ADC board for gas/steering rather than switches...

LEDs are irrelevant and only give SSIO test mode status anyway. They're 3mm yellow LEDs, there aren't really specs for them.
 
The Super CPU board:
- A couple traces had been cut & jumper wires soldered in. Behind R159 & R160 on the solder side, and next to the Analog De/Multiplexor Chip 1G (MC14053B).
Are these common mods? Or are they something you'd find on a problematic board set?

That's a factory fix on early spy hunter cpus.
 
I've got +5.12 at the chip (+5.57 on the linear power supply when the boardstack is unplugged).



if you look in the PSU guide in my signature it shows how to measure voltage at chips, I would encourage doing this to see that +5 is getting there at all. otherwise the next step I would try replacing the CPU on the Super CPU board with a known good one.
 
Last edited:
I pulled the boards out, cleaned/reseated every socketed IC, checked voltage... Still nothing (expected, but a 'reseated IC' miracle would have been nice).

Other observations:
- Peter Gunn theme plays once on startup
- If I turn off the machine, and turn it on again after a few seconds, the CheapSqueak green light blinks rapidly and the theme doesn't play. (waiting ~20 seconds before powering it up will start up with Theme playing. Pressing the reset button on the SSIO starts the board again with Theme playing)
- No lights on control panel (could be burned out - only one was working before).
- The test switch behind the coin door does not change any of the symptoms.
- Setting D14 SW#1 to "on" (on the SSIO) does not go into diagnostics -My board doesn't have LEDs anyway.


Can these things even be troubleshot without swapping the parts into a working boardset and seeing which parts won't work in it? Any pointers would be appreciated.

.
 

Attachments

  • IMG_4126.JPG
    IMG_4126.JPG
    189.3 KB · Views: 10
Last edited:
The new CPU came in, and I finally had time to mess with this again. The new CPU gives the same boot screen as before. The Peter Gunn theme now plays every time the board is reset, but other than that, there is no change.

I did notice that the screen stopped 'twitching' sometime within the last few months of working on this. Now the screen has a constant image on it.

It was while watching this Tron repair video that I realized mine was no longer resetting: https://youtu.be/ncK9yqCjd24?t=10m49s

What is the next logical place to check after repairing the watchdog circuit? Pressing the ON BD RESET (on the superCPU) will reset the CPU, so I know that I don't have a broken trace between the 4053 @F1 and pin 26 of the CPU.
Should I be looking to the CMOS Ram at B2, or something else?


Another thing stood out to me while watching: always check continuity between the socketed IC pins and the solder-side of the board.


If you look in the PSU guide in my signature it shows how to measure voltage at chips, I would encourage doing this to see that +5 is getting there at all. otherwise the next step I would try replacing the CPU on the Super CPU board with a known good one.
 
Last edited:
The watchdog circuit is functional again, and I'm looking for the next step. Just as a recap:

New Z80b
New 74ls04 @3F, 74ls161 @3H, and 4053b + socket @1G
- (the 4053b @1G had pin2 & pin5 jumped so that both pins pulled +5v from vBatt. Pin5 trace to +5v was cut. I jumped the pins on the socket and replaced the chip.)
New Caps on all 3 boards
Reflowed Headers
Replaced Ribbon Cables

I also swapped the RAM @5G and @7G just to see if it boots further (it doesn't) or if the image changed (it does).

Should I direct my attention to RAM? 6116lp-4 @2B --or-- 6116AE2 @5G/7G
Or the Z80b CTC @6G?
Or some of the roms?
 
dont know if you mentioned it but whats the status of the reset circuit?

I dont know why it works but sometimes pulling the purple or grey wire from the power supply lets the board boot. I just dont recall which wire is Batt V+ or reset right now.
 
What can I do to test the reset circuit?

dont know if you mentioned it but whats the status of the reset circuit?

I dont know why it works but sometimes pulling the purple or grey wire from the power supply lets the board boot. I just dont recall which wire is Batt V+ or reset right now.
 
Yep, I've read that over and over, and each time I get a little more out of it. Thank you!

Near the end, you talk about Pin24 of RAM@5G. I posted pics with the same question because I couldn't figure out why the jumper shouldn't have been snipped. I thought that you HAD to have one snipped... either +5v OR +vBatt (pic1).

I thought maybe it was in reference to the mod that mine has on 1G (pic2).

Did you reconnect JW14 on yours?



Your post reminds me of this

http://www.arcade-cabinets.com/fixes/spy_hunter/
I'd check to see if this is your issue
 

Attachments

  • Screen Shot 2017-10-19 at 5.50.25 PM.png
    Screen Shot 2017-10-19 at 5.50.25 PM.png
    54.8 KB · Views: 18
  • Screen Shot 2017-10-19 at 5.47.52 PM.png
    Screen Shot 2017-10-19 at 5.47.52 PM.png
    60.4 KB · Views: 21
Last edited:
So when using a switcher do you have jumper 13 cut or is there a jumper wire there?
 
What can I do to test the reset circuit?

Use your logic probe to test pin 17 (should be purple) on the power connector on the CPU board.

Reset should start low and go high. If its stuck on either that may be your problem.

Like I mentioned earlier. For some reason disconnecting this wire or the grey wire some times gets these boards going. Also, I've noticed that connecting the grey wire to +5 (V.Batt pin 16 on that same connector) gets the game to boot as well. If your power supply is missing its battery or the charge circuit is not working you may not be getting enough voltage on that grey wire. I assume the board is looking for a logic high there which would explain why connecting that pin to +5 makes the board boot.
 
Your post reminds me of this

http://www.arcade-cabinets.com/fixes/spy_hunter/
I'd check to see if this is your issue

Brien explains why connecting V.Batt to +5 makes some boards work in that link. The RAM that would normally be connected to battery voltage ISNT connected if V.Batt is not connected to a good battery or +5.

Huh, go figure. I had wondered why that works on some board and not others.
 
Mine is on a linear ps, I haven't tried it on a switcher. JW13 is present, JW14 was cut. I haven't wanted to add 'switching power supply' into the mix yet. I will definitely check the vBatt on the power supply just in case.


So when using a switcher do you have jumper 13 cut or is there a jumper wire there?
 
Mine is on a linear ps, I haven't tried it on a switcher. JW13 is present, JW14 was cut. I haven't wanted to add 'switching power supply' into the mix yet. I will definitely check the vBatt on the power supply just in case.

dont forget reset. Reset comes from the power supply and is often damaged when the original battery out gasses.
 
so whats the voltage rating on across the RAM chip (5G) in question (pin 24 to ground). also I see in previous posts you've replaced the 6116 at 5G did you replace it with a low power 6116?

you need a low power 6116 in that spot when using the battery.
(and definitely you do need to make sure the reset is also working as gamefixer mentioned)

-brian
 
Last edited:
I will check on the voltage at 5G pin24.

The 6166 in 5G/7G are CDM6116AE2, but I don't have any new "known good" ones.
Should I be substituting something like CXK5816?
TwistyWrist description: "CXK5816P-12L 2k X 8 High Speed CMOS Static Ram Low power, suitable for battery back up. Subs 6116LP"

Mine weren't 6116LP, so I'm glad you mentioned the low power thing. Does 'High Speed' make a difference?


so whats the voltage rating on across the RAM chip (5G) in question (pin 24 to ground). also I see in previous posts you've replaced the 6116 at 5G did you replace it with a low power 6116?

you need a low power 6116 in that spot when using the battery.
(and definitely you do need to make sure the reset is also working as gamefixer mentioned)

-brian
 
Back
Top Bottom