ROTJ Low Voltage Issues on Test Bench

Arcadenut

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Ok, I'm trying to test a couple of Return Of The Jedi boards on my test bench, however, when I hook them up, I'm only reading +4.5V on the board.

Brand new Switcher is being used. When not under load, the Switcher is putting out around +6V. Under load on a Burger Time, it was +5.01V, however on TWO different ROTJ boards, it's +4.5V.

Does anyone see anything wrong with the way this is hooked up? Has anyone else built a test rig for this game?


Here is how I have it wired up:

Parts Side
================
1 Ground
2 +5V
3 N/C
4 Horizontal Sync
5 N/C
6 Red
7 Green
8 Blue
..
21 +5V
22 GND

Solder Side
================
A GND
B +5V
C Vertical Sync
D -5V
E +12V
F GND



rotjadaptertopbig.jpg

rotjadapterbottombig.jpg
 
Ok, I'm trying to test a couple of Return Of The Jedi boards on my test bench, however, when I hook them up, I'm only reading +4.5V on the board.

What's the switcher rated at? Are the other voltages also being pulled down?
 
I built a jamma test adapter for rotj (it was a favor for a friend to repair a rotj and I have actually used it to repair several boards - it has a two channel amplifier and two pots to simulate the yoke) , dug it out, and it looks like you have the pinouts reversed - the solder side is 1-22 and the parts side is a-z. To help you get oriented, on the solder side in the picture that you show, pin 22 is on the bottom and pin 1 is on the top. On the component side of the board in the photo, pin A is at the bottom and Z at the top. Once you do this you should be able to figure out and correct your connections.

Here is a link to a pinout from Mike's Arcade:

http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=pinout&page=ROTJ.txt

Hope this helps - the reason you are not getting 5V is that you have some signal(s) mis-applied and probably dragging down one of the outputs through a resistive path and not a dead short. Do not apply power to the boards with your adapter until you re-do your connector as you could potentially be doing harm. It's too late at night for me to think clearly enough to translate your connections to where they are actually going on the PCB and why the 5V is being affected.

Last bit of advice - The ROTJs I have worked on have all had one or more bad roms due to bit rot. If the boards are not working, I would start by re-verifying all of the roms. Please keep us updated on your progress.

Best and have fun,

Bill
 
Last edited:
I built a jamma test adapter for rotj (it was a favor for a friend to repair a rotj and I have actually used it to repair several boards - it has a two channel amplifier and two pots to simulate the yoke) , dug it out, and it looks like you have the pinouts reversed - the solder side is 1-22 and the parts side is a-z. To help you get oriented, on the solder side in the picture that you show, pin 22 is on the bottom and pin 1 is on the top. On the component side of the board in the photo, pin A is at the bottom and Z at the top. Once you do this you should be able to figure out and correct your connections.

Here is a link to a pinout from Mike's Arcade:

http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=pinout&page=ROTJ.txt

Hope this helps - the reason you are not getting 5V is that you have some signal(s) mis-applied and probably dragging down one of the outputs through a resistive path and not a dead short. Do not apply power to the boards with your adapter until you re-do your connector as you could potentially be doing harm. It's too late at night for me to think clearly enough to translate your connections to where they are actually going on the PCB and why the 5V is being affected.

Last bit of advice - The ROTJs I have worked on have all had one or more bad roms due to bit rot. If the boards are not working, I would start by re-verifying all of the roms. Please keep us updated on your progress.

Best and have fun,

Bill

Ok, apparently every board is different :(

So if I have this correct, with the Edge connector facing you:

Looking at the Parts Side, Pin A is the far RIGHT pin, and Pin Z is the far LEFT pin.

Looking at the Solder Side, Pin 1 is the far LEFT pin, and pin 22 is the far RIGHT.
 
Correct. Another reason to appreciate JAMMA.

Bill




Ok, apparently every board is different :(

So if I have this correct, with the Edge connector facing you:

Looking at the Parts Side, Pin A is the far RIGHT pin, and Pin Z is the far LEFT pin.

Looking at the Solder Side, Pin 1 is the far LEFT pin, and pin 22 is the far RIGHT.
 
Pins A and 1 are usually identified as silkscreen on the board next to the edge connector.
 
Ok, it appears that I had the adapter wired correctly, just on upside down.

Here is a pic of it now:

rotjadapterflippedbig.jpg



Even with it on the correct way (assuming it is!), the voltage is still way too low. However, I do get garbage on the screen now, so I am making progress.

Looking at the pinout, even being on upside down, it looks like the only thing that would have been an issue would be that the +5 would have been going to +5 OUT.

On Upside down it would have been:
Code:
1 GND    -> Z  SW GND
2 +5V    -> Y  +5V OUT
3 N/C    -> X  N/C
4 HSync  -> W  N/C
5 N/C    -> V  N/C
6 Red    -> U  Vertical
7 Green  -> T  Coin Left
8 Blue   -> S  Self Test

21 +Sense -> B +5V
22 -Sense -> A GND

C  VSync   -> 20 Horizontal
D -5V      -> 19 N/C
E +12V     -> 18 N/C

So now both boards show garbage on the screen, and both still show low voltage. :confused:
 
Ok, hooked the Switcher's +5V directly to the connector using 12GA wire (about 1.5' long wire) and cranked the PS up to max, and got as high as 4.8V, but nothing above that. :(

So at this point, is it safe to assume a short in the board somewhere?
 
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