Defender troubleshooting help

dandydan1959

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Hi,

I have a new defender that I am working through issues on. I started with four leds on constant and no rug pattern. I found light acid damage and repaired that and replaced sockets near that area. I now have a rug pattern test and four lights come on for a few seconds and then flash off and the I see from left that the first and third leds light for a moment and go off and then the second and fourth from left light and stay lit. Been about twenty five years since I repaired one of these and I am not sure how to interpret the leds. I have the operators manual and I can not match the patterns.

0= on and X=off

First all 4 on OOOO
Then 1 and 3 0X0X just a couple of seconds
Then 2 and 4 X0X0 remain lit

Thanks for your help,
Dan
 
Hi,
Yes,
Voltages are in tolerance by specs.. Hoping someone could help me with led sequence from start up.
Thanks
Dan
 
Ok got a little further

It looks like my Rom 9 is bad based on the troubleshooting guide. These appear to be 2532's. Based on Bob Roberts web site he said you could pull the bad chip to see if it cleared the error code. I pulled this chip and all four lights went in the following sequence

From left to right
O=on and X=off

Before removing Rom 9
oooo for a few seconds
startup sound
OxOx for a second
X0Xo solid
rug pattern continues to reset after two scans

After removing Rom 9
oooo for a few seconds
Startup sound
XXXX
rug pattern continues to reset after two scans



Going to look for a ROM 9. If you have one to sell let me know.

Thanks
Dan
 
Give Hobby Roms a shout (KLOV user Steph). He should be able to burn you a complete set to save you the pain of finding the next bad ROM in the sequence.

ken
 
I purchased a second set of boards. I will update you when I start working on this later in the week.
Thanks for the input.
Thanks
Dan
 
Hi Guys,

I got my new roms and the lights come on until I hear the game sound then all go off and stay off. I am still getting the rug pattern and it reset's every two scans. I am going to start through the watchdog circuit.

If you have any words of encouragement please chime in.
Thanks
Dan
 
Another question

Hi,

I am stuck on this issue. I have a question for someone advanced regarding a minimum configuration for troubleshooting. Using a standard switching power supply can I wire up the mpu and rom board and Interface board and troubleshoot from the bench without the other cabinet wiring? Troubleshooting sitting on the floor is not a very optimal setup.

Let me know if you have ever done this before and know it will work. I can;t think of any other way to get the boards out where I can work on them except for creating a extension harness.

Thanks
Dan
 
That is how I have my bench wired up. A switcher is much smaller than a power brick + PS board + heat sink assembly.

The easiest thing to do is follow the wiring diagram that is in the Defender drawing set and you should be able to build a test wiring harness fairly easily. Or if you have a spare Defender wiring harness, you can just get a 15 pin header and wire the voltages up.

Where the wiring diagram lists +12V unregulated, just tie those to the +12V from the switcher. +5V to +5V and -5V to -5V and you will be set.

Just lay it out all the boards and where you are going to place the switcher. Then you can use a piece of string to measure the length of the wire you will need. DOn't forget to add a few inches onto all the wires so you have room to rearrange things if needed later.

ken
 
One step forward and two back

Wired up rom and mpu to a switching power supply. Found 7j bad. Also found ribbon cable on the rom board needed to be crimped. Got to booking mode. Could not get it in to game mode. Left it on for a while as I trouble shot and after about 30 minutes I was getting ram errors and CMOS errors. Thinking power supply since these were random.

Dan
 
Stuck again

hi Guys,

I had the boards working to a point that it came up all system go. Then went into book keeping. I replaced the battery pack and restarted the boards and still could not get out of book keeping. I was getting two flashes of four leds after startup so that was working consistently. I left the game on for several minutes and when i restarted it it came up with a ram failure. I replaced the ram and it came up with a second ram error. then as I stepped through the test it also reported a cmos error. I returned these boards to the bench thinking my power supply might be bad and the watch dog timer issue is back.
The WDT pulses every 5 to ten seconds.

I have a question or two.
1. When you cut the pad for the WDT do you need to do anything else? I had a theory of op manual that said to ground the input of 0d gate also.

2. When I cut the WDT pad how do you isolate the inputs to see which one is the culprit? I have placed a probe on the inputs to the nand gate. Are there inputs in particular I should look at?

3. the rom board did not display any errors when I had the game working. I was able to get it to self test also and it passed. I think it is good but have no way to test it.

I have two MPU boards that have the same issue and symptoms. When using the flow chart I have WDT pulsing every 10 or so seconds. If I continue on through the tests everything is working until I get to 5P pin 6. I have isolated pin six and still no pulses.
Will that pulse if the WDT is strobing?

I wish I had a good unit to compare it to but do not. I appreciate your help. I have read as any post's as I can find on this issue. It seems people mostly upgrade the ram and then replace the ROM's as needed and then they are good. I would like to see which Ram are bad
Thanks,
Dan
 
The Theory of Op manual suggests grounding NOR gate 3D after you open the solder jumper (doing so will just keep the watchdog reset permanently deasserted). I presume one could also just pull the 74393 counter reset line high to have a similar effect.

Since most of the NAND gate inputs are for decoding the watchdog reload address/data, I'm not sure there's much value in probing that (other than to confirm the CPU is hosed / in the weeds and not writing it).

LeChuck
 
defender is alive but still struggling

Hi,

I found the issue was the rom board. I swapped roms between the old one and another one i purchased for a spare and for parts.

I am getting immediate sound, two flashes of all four leds and initial test's ok. The screen is flip flopped- upside down but perfect is this cocktail ROMS???. Comes up in Book keeping mode. When I try select special function 28 and then advance I see it tries to do something and has white dashes for a couple of seconds on screen and then comes right back to set up. Can not get special function 28 to a value of 35. It goes to 17 and then qoes back to zero. Battery holder and voltage to CMOS is good.

Things I have learned,
Rom board will stop the CPU from working. Failure mode is all lights on for a few seconds and then the WDT clears them and then the rug pattern continues to repeat and clear after two scans.
If you disconnect Rom board from MPU and the video comes up with Black and White jail bars you most likely have a good MPU or close enough to get to test screen if your rom board is good. Learned this from another post.

If anyone has a idea of what to do to get out of book keeping and wants to sell a set of ROMS please let me know. I have a mixed set now and this screen flip flop thing must be related to that. Switched the vid decoders so that is not the issue.
Thanks,
Dan
 
You can get a complete set of ROMs burned for you from Hobby Roms (klov user Steph). That is probably the best solution to ROM issues.

The screen flip is controlled by a jumper on the IO card. According to the notes on the schematics for the IO card:

FOR COCKTAIL TABLE GAMES, W2 MUST BE
CONNECTED AND W1 MUST BE REMOVED.

FOR UPRIGHT GAMES, W1 MUST BE CONNECTED.
WITH RED-LABELED ROMS, W2 MAY
BE CONNECTED OR REMOVED. WITH LABELS OF
OTHER COLORS, W2 MUST BE REMOVED.

Hopefully that will flip the screen for you. The other possibility is that somebody had a game running on that monitor and the yoke connections have been swapped to flip the monitor. Check on Bob Robert's site, I believe he had a detailed explaination of how the yoke connections are swapped. Then you can check to see if that has been done to that monitor.

ken
 
Still stuck

Hi,

I have not swapped the I/O card. The screen was acclimated correctly last night when I had it working. Is there anything else that would cause the screen to flip? Still can't get out of bookkeeping mode. Have tried all combo's of special function 28.

I checked voltage at CMOS pin 22 to pin 8 and it is 3.76V. Starts at +4.1 at batt pack. After diode it is +3.76 and at pin 22 it is +3.76.

Checked mem protect switch and it shows continuity from pin 4 to ground when door closed and open when open.

I can't tell if the CMOS is tested in the initial test program. Does anyone know if this is the case? Cmos failed last night when I was able to get it into test. I have a cmos. Should I remove and replace the CMOS?
Thanks
Dan
 
Yes, ther is a pin on one of the decoder roms, which, if pulled high, will flip you screen. This is how the IO widget communicates to the MPU that, for user 2 the screen should flip, BUT just perm pulling this pin high perm flips the screen [like to fix a hardware flip as another poster suggested].

Hi,

I have not swapped the I/O card. The screen was acclimated correctly last night when I had it working. Is there anything else that would cause the screen to flip? Still can't get out of bookkeeping mode. Have tried all combo's of special function 28.

I checked voltage at CMOS pin 22 to pin 8 and it is 3.76V. Starts at +4.1 at batt pack. After diode it is +3.76 and at pin 22 it is +3.76.

Checked mem protect switch and it shows continuity from pin 4 to ground when door closed and open when open.

I can't tell if the CMOS is tested in the initial test program. Does anyone know if this is the case? Cmos failed last night when I was able to get it into test. I have a cmos. Should I remove and replace the CMOS?
Thanks
Dan
 
Need Rom images

Hi,

I just got my programmer working and I need Rom images to compare my roms to. I see references to mame roms but assume these are not working roms. I have red label roms. My Rom 11 and 12 both have some gaps or 11 00 lines at the start of the rom and mixed within. The legs from my second set of roms were so brittle that they fell of when i removed them so no good to compare.
Could someone point me in the right direction to get this code?
Thanks
Dan
 
Rom check sums wrong

Hi
Rom 2 and3 check sums are wrong. All others are correct. I am looking for images for rom 2 and 3 red label.
Thanks
Dan
 
Roms 2 and 3 are 2532 eproms,
unlike all the others which are 2716.

I'm guessing you probably checked them as 2716,
which is why they showed as bad...

---

Also check the ribbon cable between the ROM board and CPU board.
These often go bad and cause all kind of weird problems..

Good luck,
Steph
 
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