What inputs are you seeing on the 7447 (pins 1,2,6,7)
When you say "no outputs", you are reading neither high or low on the outputs?
(Topic ID: 251495)
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Black Knight
Williams, 1980
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Quoted from pincoder:It's worth mentioning that upon normal power up, the LEDs do flash and the zero shows up on the LED segment display. This occurs before the CPU starts executing any instructions. The first bit of code in any ROM should be to initialize the PIAs and that's when you see the LEDs and segment go out. The zero means nothing really. It is not the result of some test being performed in any of the pincoder ROMs, and I would also suspect is true for the Williams ROMs. It's just how IC33 and IC34 power up in this circuit.
With the Williams ROMs, the number will stop on the test or initialization that fails:
0 Test Passed (only if display goes blank)
1 IC13 RAM Faulty
2 IC16 RAM Faulty
3 IC17 ROM 2 Faulty
4 IC17 ROM 2 Faulty
5 IC20 ROM I Faulty
6 IC14 Game ROM 1 Faulty
7 IC26 Game ROM 0 Faulty
8 IC19 CMOS RAM or memory protect circuit faulty
9 Coin-door closed, memory protect circuit faulty, or IC19 CMOS RAM Faulty
If 0 is left on the display, the CPU is not running. If 0 flashes for an instant and the display goes blank, it is running.
Quoted from kevinclark:Plugged my boards back in and I'm able to get to audit mode! Digits test runs fine. That's the good.
The bad is:
* The big resistors on the bottom right of the driver board are running crazy hot and seem to have burnt the board. I can smell it when they turn on. I've got IRF9Z34Ns on hand and am going to replace the TIP42s and resistors, but seems like there might be an underlying issue there.
* Sound test has no response, though sound diagnostic button works fine.
* Solenoid test has no response. Test 25 or coming back to 1 makes a clicking sound like a relay flipped. Maybe IC 5 PIA bad too.
* Switch test replies with 38 37 35 34 33. So column 5 seems like it's having some issues, but not across the board.
* Lamp test has no response. Thinking IC 10 PIA is bad.
Those resistors do run crazy hot, almost 200F when everything is working properly. It gets worse if you still have incandescent bulbs in the machine. The MOSFETs will drop that down to a little over ambient.
I lost track with what you have done. Have you replaced the 40 pin, ROM and CPU sockets, header pins around the boards? Those are typical problem spots that I always replace before killing myself chasing other symptoms.
Quoted from pincoder:I'm still working on that board, and it'll be much more than just a simple board. Stay tuned. In the mean time, a ZIF wouldn't hurt
Can't wait for your board to come out.
Agree, solenoids can be fired by either the special switch inputs OR the ST1-6 signals from the various PIAs. The PIA and special switch input are combined at the 7408 AND gates IC6 and IC7 then combined with the blanking signal through the 7402 NOR gates IC8 and IC9, then drives the pre-driver and power transistors.
Quoted from pincoder:It's nice to see that other people are also following along and watching for misinformation!
I did some testing, and I was wrong. Thank you for pointing it out. The ST1-6 solenoids CAN be fired from the CPU. See attached for test cases.
Having said that, perhaps I should rewrite 10-solenoids to also fire the ST1-6 solenoids. Thoughts? Can you think of an example of a game and condtion where the CPU would actually do this? Possibly a ball search? Does any system 3-7 game even do a ball search?
Let me know what you'd like to see in the 10-solenoids ROM
[quoted image]
Edit: "B" ST6 Enable is what I've been calling the PIA1 PB2 pin. I'll need to rename it
No ball search that I know of but some games will fire solenoids at the end of a ball. For example, Firepower will fire the "lock" solenoids to eject any locked balls at the end of a game or whenever a ball is detected in a saucer at power-up or during game over.
Black Knight programmatically fires solenoids in the 2 ball lock areas to release balls.
Blackout programmatically fires the solenoid in the saucer
This type of test would be a valuable add IMO.
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