Joust Won't Boot

zz0ljf

Active member
Joined
Dec 13, 2008
Messages
463
Reaction score
66
Location
Chesterfield, Michigan
I bought a non-working Joust off Craigslist yesterday for $100. When I picked the game up the power supply wasn't outputting +5V at all so the game wouldn't even attempt to boot. I got the game home, opened it up, and to my surprise discovered $35.25 in change!!!! So essentially I paid $64.75 for a non-working Joust. Not bad huh? After removing & reseating all the IC chips I found that the CPU chip and one 4116 RAM chip were seated backwards. Now the game boots up with the screen below. Measuring the voltages at the power supply I get +5.08V, -4.75V, & 11.84V. If I measure the voltages at a 4116 IC chip I get +4.79V, -4.75V, & 11.74V. Is this just a case of some bad RAM or is the problem larger? From the manual the voltages seem to be acceptable. Any advice would be appreciated.
 

Attachments

  • IMG_2169.jpg
    IMG_2169.jpg
    86.8 KB · Views: 43
  • IMG_2165.jpg
    IMG_2165.jpg
    92.8 KB · Views: 40
  • IMG_2164.jpg
    IMG_2164.jpg
    94.3 KB · Views: 65
I did not replace them are they both presumably bad due to being socketed backwards? One was the 6809 CPU and the other was a 4116 RAM chip.
 
I did not replace them are they both presumably bad due to being socketed backwards? One was the 6809 CPU and the other was a 4116 RAM chip.
The picture of the screen looks like a messed up rug pattern - if that's the case then the CPU may be working. I'd expect the 4116 to croak from being in backwards. I'd also try to find out where the rest of your 5v went, I think 4.79 may be too low. Check the header pins for corrosion, reflow the solder on them, and check the connector
 
When you say header pins what pins are you referring to? The pins for the main PCB wire harnesses, or the pins for the 4116 sockets?
 
Ah, at least I know where that one went to. It vanished pretty fast off of CL. If you end up needing some 4116 RAM send me a PM.
 
The RAM chip is a total loss . When it gets plugged in backwards it fries in seconds.

You might also want to try reseating all of the cables. It is not unusual for corrosion on the power connectors to lower the voltage significantly.

Are there any numbers flashing on the 7 Segment LED on the ROM card. It should be outputting some diagostic information if the CPU is running.

ken
 
I will most certainly need some RAM chips just trying to figure out what else I might need. As for the LED display it's hit or miss, but mostly miss. The majority of the time the LED is blank, but on rare occasions I've been able to get something to display on the LED and a Joust sound effect or two to play, but the screen always comes up garbled. I didn't note what the LED did display the one or two times I got it to light up. Next time I'll take note. What do you guys think about the CPU chip is it fried from being in backwards or possibly still good? How about the power supply? Should +5.08V off the PS be sufficient, I'm just not getting enough voltage to the PCB for it to boot up? Would fried chips on the PCB possibly be causing the voltage drop? Just curious what reading ones gets on a fully function Joust. I'll reflow the header pins when I get some time and see what I get. I have reseated all the cables except the SCSI cables? On end looks like it's permanently attached to the daughter board. Is this the case, or should I be able to disconnect it from both boards?
 
The guy I bought it from swore it worked fine for years and then just all of a sudden started displaying garbage on the screen during game play and eventually that's all it would display. I tend to believe the guy because he couldn't even figure out how to get the game open let alone get the quarters out of the coin bin. However I do find it odd that the CPU was in backwards as well as one 4116 RAM chip and yet he claimed the game used to work and I sure he wasn't in there reseating IC chips. Very strange....
 
I wouldn't worry about why the chips were backwards. He probably had a friend that can "fix anything" take a look at it.

There are a bunch of KLOVers in Michigan that can probably hook you up with some RAM chips or the last time I priced them Unicorn Electronics had the best small quantity price of the common retail operations. DRAMs (4116 200ms) were $0.59 each and 6809E CPU chips were $3.49 each. Make sure you specify 6809E. The straight 6809 chips won't work.

You may also want to pull the connector from the ROM board and recrimp it. They get funky over time as the wires work loose from the IDC pins. Here is a link that will show how to recompress the connectors: http://www.arcadesolution.com/ribbon.html

ken
 
I reflowed the header pins and now I get +4.93V at the RAM chips but I still get the messed up rug pattern. RAM chips are on the way then we'll see what I get. Still nothing on the LEDs
 
68B09EP was a 2MHz replacement for the 6809E. It will work fine. The E designator indicates that it uses an external clock. Which is necessary to work with all the other chips (they need to be driven off the same clock to synch correctly). The 6809 (no E designator) used an internal clock and was good in standalone circuits but it didn't like interfacing to shared bus systems.

68B09E processors will run at 1Mz that is generated by the crystal on the CPU board.

ken
 
Try flexing the ROM connector cable a little bit and pressing the reset button on the MPU board. If the connector cable is not contacting the wires correctly it will act that way.

ken
 
If you want to ship them to me, I will take a look at the boards. It is very hard trying to diagnose things via message posts. I repair Williams boards and unlike the commercial places, I don't charge for evaluations, just for return shipping. If I find anything wrong I will let you know and you can make the decision on how to proceed. If there is nothing wrong with the boards then at least you know that works and you can look at the infrastructure for answers.

Send me a PM if you are interested.

ken
 
Back
Top Bottom