Tempest PCB

[Zektor]

I've had this sitting around for years now, originally purchased on ebay (USA)

Upon power up I noticed the power reset circuit had the 10.6v missing, I only have the loom and from looking at the schematics the coin door needs to be plugged in for it to loop to the PCB. Anyway after sorting that, I found an address line of ls244 at BC1 pin 16 (AB2) stuck low. This is one of the address lines for the program Ram and Rom.

That's as far as I got today, hopefully remove the 2 RAM chips tomorrow and see what's what.

 

[Alpha1]

Zektor! Welcome back!

 

[Zektor]

Zektor! Welcome back!

Cheers Ol! 3 house moves later and my test bench is set up again....will continue with the Star wars Repair thread once tempest is fixed.

 

[Zektor]

Ok so I found the 74244 ac B/C1 was faulty, pin 7 tied to ground. Powered up and now I get more activity on the data and address lines with the Watchdog disable tab grounded. I found another faulty 74244 at A/B1, replaced and now the CPU is running without Watchdog disable tab grounded.

I have another problem now in that the loom I'm using seems to wired incorrectly....I have no - / + 22 volts to the main PCB. The PCB connectors 3 and 4 have 2 small white wires running to the 5v side of the AR2......I'm pretty sure its a tempest loom as it came with the spinner and buttons still attached. If anyone here with a Tempest could take a pic of the AR2 connectors and PCB connectors I would very much appreciate it.

Here are a few shots of mine, only one set of wires coming from the 22v side of the AR2 :-/

 

[Monstermug]

From the schematics, +22v comes out of pins 1 and 2 (J10) of the AR2, while -22v comes out of pins 3 and 6 (J10). If you're not getting +/-22v from those pins on the AR2 then check the bridge rectifier and/or caps at C18 and C19 and if you are getting 36vac from the power brick. While you at it check if R32 is 5.6k too.

+22v and -22v from those pins should go directly to X/3 and W/4 respectively on the 44 Pin edge and 3/P and 4/N on the 30 pin aux board. From memory, +22v and -22v have link traces that runs to the other side of the board so there may probably be only one wire for each.

 

[Zektor]

The AR2 is known good.....I'm getting + and -22 on the Aux Board.

I just checked the harness part number...arghhh I was sold a Star wars harness with a Tempest spinner and buttons plugged into it )

So I now have 3 complete star wars harnesses...time to hit the for sale and wanted section.

 

[Monstermug]

Ha that makes sense although I be mildly worried about where the 10.3 vdc on the star wars loom has gone to on the tempest PCB though.

 

[Zektor]

Should be fine, it was connected to the right coin counter output.

 

[Zektor]

More progress on this. I spent the day setting up my KK TF650 test unit. I knew I had 2 of the 3 cards needed to run a tempest PCB and managed to make the 3rd using a straight through 25pin card and a 22 pin adaptor.

The PCB will run now, I can hear sounds but haven't confirmed any video output, I need to make an adaptor for my ZVG vector to LCD unit.

Here's a shot video of the KK unit.

https://www.youtube.com/watch?v=tggnIaH2wJAZektor2017-04-08 21:14:00

 

[Zektor]

More progress on this today, man this was a bitch to fix.

I found a bad trace on the underside and along with replacing a flaky D7 PROM socket the board starting showing more signs of life. It was still far from "working" but I could see parts of the Vector Data at the DACS. I found a dead MC1495 in the XY output stage, hooked up my scope and got a weird curved line on the display.....only in test mode, game mode was still playing blind.

After a lot of testing I found the Stack and program counters were static due to OP0 being static. Pin 3(op0) of D7 Prom was static and in turn LATCH2 and Strobe2 were inactive. I checked the Prom by reading it as a 74288 in my chip tester and comparing it to the Prom in Space duel.

I eventually found a stuck output on pin6 of B9(74ls32)this was stopping the AVG0 signal from being generated which allowed the game to play blind and not cause a reset, pulled the chip and sure enough it was dead. Fitted a new chip and Bingo!! it lives!!Zektor2017-04-24 11:37:22

 

[Zektor]