Defender OMFG what have I done???

Rat

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Just installed my new JROK board for my Defender cab, all went well, loving the JROK and playing Defender and Stargate :D

But then I thought before retiring the original boards which had been working perfectly, I would recheck the scores and settings.

Replugged the leads, and found no video output, monitor came on but nothing displaying.
Still had sound for power up, and four leds on rom board lit once at power on.

Then I checked around and found the sound stopped working all of a sudden.
Bugger...................yeah the jrok is better than ever, but I want to know that the original boards work :(

I noticed I left the 3 pin power plug connected to the original ROM while playing jrok, could that have caused a problem????
 
Possible, but more likely you pulled some wires loose on the ROM cable when you were messing with it. Try pressing down on the ROM connector while supporting it from below with your fingers and see if it will boot. You may need a second person to help with powering the game on and off.

ken
 
Possible, but more likely you pulled some wires loose on the ROM cable when you were messing with it. Try pressing down on the ROM connector while supporting it from below with your fingers and see if it will boot. You may need a second person to help with powering the game on and off.

ken

I had another go at it today, but I didn't do it exactly as you said, I should have re-read your post before my troubleshooting session, I will try again in a few days when my work shifts are over and do it like you suggested.

Anyway I fiddled with all connections while my son watched the screen, nothing, I checked all the wiring connections at the plugs, and reseated a couple of wires that looked like they could have been dodgy. I checked the solders on the back of boards at the connection pins, looked good, they have been re-flowed already.

One thing I did notice was after it had been on for about 10mins two leds light up on the ROM board, the left two. I had not been running through any diagnosis tests, as I can't without a display or sound. So I'm unsure if this is giving me the same result as if a test had been run? This website says that indicates IC12 ROM failure http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=info&page=DefenderErrorCodes.txt

I tried re-seating the IC12 ROM, nothing. So next week I will try again with the ribbon connector while turning on and off, try cleaning and re-seating that ROM again and post results.

mr.fixit, thanks for your offer, but I'm reasonably sure that I have it all plugged in correctly, I labeled the wiring and plugs, and it works fine on the jrok board, so it can't be a plug or break in a wire.
 
Found some time to have another try, reflowed the solder on the connectors on the ROM board just in case. Fiddled with the ROM board ribbon connector and found that it's not a very good connection, the ribbon is not held very tight.

But now after doing that it's booting up to a solid color screen, changes from blue to red etc, but just a solid block of color, nothing else.

Also found that one of the pins on ROM #3 in broken, not sure how it played OK before, maybe the pin stump was just making a connection before? Anyway tried fixing this, I stuck a pin down the side of the leg with the chip seated. It looked like it made a good connection, but maybe not?

So I'm looking into ordering a new ROM chip from Arcadesolution.com, he is out of office for a couple of weeks. Anyone know another ROM chip supplier?

I already have a new 40 pin ribbon cable ready to install, and I will try that when I find time and post results.

Can anyone tell me if they think that either of the issues (ROM Chip or ribbon cable) would cause my sound to also stop working? When this issue first appeared the start up sound still came on at power up, now it doesn't.

Jrok board still working fine, better go and have a game, need a ride on my MTB first to de-stress :)
 
Steph at Hobby ROMS (www.hobbyroms.com) is my ROM go to guy. His user name on KLOV is STEPH. PM him and I'll bet he can get you what you want shipped in a day or so.

It is sounding more and more like you may have a power supply issue. You can check the voltages on any RAM chip. The supply voltages on 4116 can be found on the legs in the 4 corners:

picture.php


ken
 
Today I had some spare time so I tackled the job that would take the longest, replacing the old 40pin ribbon cable with a new one, did a good job, but this wasn't the solution.

Also had another go at replacing the pin on ROM chip#3 the pin looks OK, but it also looks like my stuffing about with replacement pins has damaged the contact in the chip holder. So I'm going to order both from Steph.

Then I got round to the easiest job, measuring the RAM chip voltages as suggested by YellowDog.

YEP I have a voltage problem there for sure PIN1= -5, PIN9= +5 (Both very close) but PIN8= +3.90

Now to figure out how that happened, and how to fix it????? First thing that comes to mind is perhaps I cracked a solder joint on the power connector pins for the main board, I will check that.

I assume my power supply is delivering good voltage as the Jrok works perfectly. Previously I put a trimpot on the power supply as in this tutorial http://cambridgearcade.dyndns.org/?q=node/76 and adjusted it and had it all working perfectly.
 
YEP I have a voltage problem there for sure PIN1= -5, PIN9= +5 (Both very close) but PIN8= +3.90

I assume my power supply is delivering good voltage as the Jrok works perfectly.

The JROK board only requires +5VDC. The original boards require that as well as -5V and +12V. So it working with a JROK board is a necessary, but not sufficient, test.
 
OK tested the power output pins at 4J2 on my PSU Board with the following results.

1= -5.1
2= key
3= 11.69
4= -14.06
5= 13.60
6= 13.60
7
8
9
10
11
12= 5.19
13= 5.19
14= 5.19
15= 5.19

AFAIK that seems to be OK? so I suppose next I will have another look at the wiring from the pins to the main board and the solders on the main board connector.
 
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WOOHOO stop looking :) fixed :D

I checked the voltages at the plug ends of the wiring and all seemed OK, so then I moved to the solder on the main board power connection pins. They looked good and had been reflowed when it was refurbished, I had already checked them before and decided that was not the problem. But it turns out it WAS them, I reflowed and it ALL works now :D

This proves that my other work was good also, cool, even the ROM leg, but I will still buy a replacement for that.

Thanks to YellowDog, mr.fixit and DarrenF, your contributions helped me keep looking and to expand my understanding :D
 
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