My Williams Black Knight not booting at all.

[PinPal]

I have a major problem with my Black Knight, after powering it up yesterday the game is compleatly  dead except for the G.I. lamps. I checked the  power board and transformer, both ok.
I even put my Rottendog  c.p.u. /driver from my Flash over  to Black Knight and the machine went into attract mode when powered up.
Something has gone bad on my System 7. c.p.u.
No led flash and no digit on cpu display when the board is powered up  
I checked all fuses as well, all ok.
I am still learning how to repair my own games but this has got me stumped.
Eney help would be appreciated.

Pinpal .....

[Marty Machine]

Hmmm,. try the absolute minimal system.

Unplug all other boards & connections from the cpu to other boards, this includes the power driver board that plugs onto the MPU.

The only things left connected should be the main power supply and the MPU board...

Powerup and see if you get the MPU LEDs flash (or not).

If no flashing, then you have MPU problem.
If the LEDs do flash, then re-connect the other boards 1-at-a-time (poweroff between each reconnection) and note which connection or board then makes the MPU LEDs stop flashing to find the culprit.

MM

[PinPal]

Thanks Marty,
I did try that to but without success,  will have a another look tonight but something has gone bad. Replaced the game rom chips  not so long ago and have had no trouble till now. Will have to get Rod Brooks over from the Pinball people to check it out.
Pinpal...

[Strangeways]

Reseat the Eproms. Sounds like something simple.

[PinPal]

Will try that tonight, I did reaseat sum of the chips with sockets but not the eprom.

Pinpal...

[Marty Machine]

Thanks Marty,
I did try that to but without success,  

If you followed the steps to unplug external boards, the result on the MPU is either working, or not working, then from there the next step was to re-plug in each external board until the MPU faulted (no leds etc).

If the MPU board alone (attached only to power supply) does not boot/flash leds then the your MPU is potentially stuffed, although you still need to prove ALL supplies on the power supply board are correct, 5volts, 12volts etc etc.
If power supply is wrong, MPU will never boot correctly for a start.
After confirming all that, then you'd look into corroded eprom sockets and so forth.

MM

[MartyJ]

Have you reseated the CPU board to the driver board?

From reading above you've done the connectors, but this one is probably worth trying.

[PinPal]

Yes, I have reaseated the interconnectors but still dead.
I will reaseat the game epromes and se if eneything changes.

Pinpall...

[Retropin]

Yes, I have reaseated the interconnectors but still dead.
I will reaseat the game epromes and se if eneything changes.

Pinpall...

In all honesty, you are stabbing in the dark right now. Check the voltages from the power supply. If all are good then start looking at the CPU and check the test points there. You really need to eliminate the basics first.
I know it worked fine until now but all machines do until they don't.. that's what makes them not work anymore.
Im assuming you've tried staring at it for prolonged periods of time to see if it will fix itself??

[Marty Machine]

Im assuming you've tried staring at it for prolonged periods of time to see if it will fix itself??

I've tried the Jedi mind trick for years now, it's all BS, it doesnt work ;-)

[Retropin]

Im assuming you've tried staring at it for prolonged periods of time to see if it will fix itself??

I've tried the Jedi mind trick for years now, it's all BS, it doesnt work ;-)

Often do it myself... one day I will crack the technique!