defender help needed.

tals7

New member
Joined
Sep 1, 2010
Messages
216
Reaction score
1
Location
plymouth, Michigan
hi, i just got a non-working but complete nice defender.i power it up and see these screens,but no sound.all of the lights are lit on the ps board(bottom of cab).if i press the thing on the sound board it keeps makeing the start up sound until i turn the game off.also the 4 lights on the rom board stay lit.i did notice that there is no batts in the factory holder,not sure if this would mae a difference?.any help on what i should do first?.thanks for any help.
 

Attachments

  • defender1 001.jpg
    defender1 001.jpg
    89.2 KB · Views: 20
  • defender1 002.jpg
    defender1 002.jpg
    90.2 KB · Views: 23
  • defender1 003.jpg
    defender1 003.jpg
    91.7 KB · Views: 25
hi, i just got a non-working but complete nice defender.i power it up and see these screens,but no sound.all of the lights are lit on the ps board(bottom of cab).if i press the thing on the sound board it keeps makeing the start up sound until i turn the game off.also the 4 lights on the rom board stay lit.i did notice that there is no batts in the factory holder,not sure if this would mae a difference?.any help on what i should do first?.thanks for any help.

First=Check the power supply voltages.
 
i was looking at the rom board.and it seems that the rom 9 was in the place where rom 5 would be.i thought rom 5 was open?.when i pulled rom 9 3 of the legs were broken,is there a place where i could get a new rom 9?or a complete new set?.
 
Send a pm to STEPH, he runs Hobby ROMS and he can burn you a new set.

The sound board is a completely seperate entity (has its own CPU chip) so pressing the reset button causes it to start playing sound 1 over and over again until it is powered down.

As stated earlier, test the voltages being put out by the power supply board. The lights are a good indicator that the voltages are there, but they can be too high and the LEDs will light as well.

Based on the screens, it looks like you are having startup issues. Not too surprising for a Defender. Once you get the new ROMs (or you can try soldering new legs from a donor chip onto the old ones that broke off as a temporary fix) you will need to check the startup sequence. Normally all 4 LEDs blink, go out and then come back on. Based on your description, since they didn't even blink, it probably means that the CPU is not running. This could be due to bad ROMs or the ROM cable may be bad and need to be recrimped or replaced.

Another thing to check is for corrosion in the chips around the crystal (the small silvery component about 1/2 way down the long side of the MPU board). If there is corrosion here, it may mean that the clocks (the heartbeat for the cmponents) are not being generated correctly. This will cause the CPU chip to not function.

ken
 
ok,thanks.how would i go about doing that?.i have a digital volt/ohm meter,where would i put the red/black probe?.sorry for the basic questions,just new to this.

Set the voltmeter to DC voltage (most have a setting for 20 volts). Put the bloack (common or COM) probe on the wide copper trace that goes all the way around the board (or if it is still mounted in the cabinet, you can touch it to one of the mounting screws). Then touch the red probe to the connector wires that lead to the game boards.

The other wires that go back to the transformer carry AC voltages.

If you do not have the Defender drawing set, you can download it from arcarc.xmission.com. In the drawing set are component layouts and schematics for all of the boards and cabinet wiring drawings. These are essential if you are going to figure anything out.

ken
 
Set the voltmeter to DC voltage (most have a setting for 20 volts). Put the bloack (common or COM) probe on the wide copper trace that goes all the way around the board (or if it is still mounted in the cabinet, you can touch it to one of the mounting screws). Then touch the red probe to the connector wires that lead to the game boards.

The other wires that go back to the transformer carry AC voltages.

If you do not have the Defender drawing set, you can download it from arcarc.xmission.com. In the drawing set are component layouts and schematics for all of the boards and cabinet wiring drawings. These are essential if you are going to figure anything out.

ken

thanks,i will check voltages and download the drawing set.tried to pm steph,but there were many different names(there were either numbers or letters after the name"steph".if the voltages are good,would my next step be to replace the roms?.when i first started the 9 rom was in the 5 position,and now i dont have a working 9rom(legs are broken flush with chip).thanks for all of the help.
 
"thanks,i will check voltages and download the drawing set.tried to pm steph,but there were many different names(there were either numbers or letters after the name"steph"."

Hobbyroms.com Perhaps, just guessing?

Yep...here's the link, http://www.hobbyroms.com/

Did a great job burning the two video decoders for me. Worked like a charm! He's in Canada, so shipping took 14 days.
 
Last edited:
Here's a good link that walks you through checking each of the ROMs necessary to get a failure message:
http://www.arcadesolution.com/rom.html

Note that the jail bars are a symptom of the first ROM (3) being bad/missing .. so my initial guess would be either the ribbon cable connection is dead (preventing any code fetches at all from the ROM board), or your voltages are off (preventing most anything from working, incl. ROM access and CPU execution).

LeChuck
 
thanks for the help guys.i just checked the voltages at the 1j3 on the cpu/video board.got -5.16 +12.8 and +4.6 .these were close but not the -5/+12/+5 the drawings showed.there is some light acid damage(i looked at both sides of board)but all chip legs and other parts seem to be intact.i am going to order some new 40/20 pin ribbion cabels along with the rom set.is the power supply bad,as the readings were off?.thanks for all of the info.
 
The 4.6V measurement should be right around 5V, although I would expect the board to get further than jail bars if that were the only problem.

As far as debugging the low voltage - I would first determine if you're getting 5V at the power supply itself; there are several test points available for this (I typically measure 5V at the leg of the resistor to the left of the connector). If that's good, you can follow the wiring/connectors to see where the voltage is dropping.

LeChuck
 
update

well i talked to andre today and ordered a cpu board(with 4164 ram upgrade),rom board and powers supply.thanks to all of you who did help.hope to report back soon with a working defender.
 
Back
Top Bottom