Double dragon won't boot

GoneMad

Well-known member
Joined
Mar 15, 2011
Messages
1,347
Reaction score
36
Location
Cavendish, Prince Edward Island, Canada
I'm trying to resurrect my Double Dragon. It does not boot at all. When it turns on, I just get some noise or static from the speaker and the volume controls works on it and that's about it. Voltage all checks out fine. What tools I have to work with here, Knight 610B logic probe, DMM, and the rest of the usual tools. I do not have a scope. I have done some reading and see the problem could possibly lie in the CPU/Clock area. This is the 6809E chip with the external clock. Monitor chassis are pretty easy to find one's way around on, but game PCB's are a bit different. Any help to determine if I should shelf this for parts or actually find out if it's fixable or not would be appreciated. THX
 
http://www.cpu-world.com/info/Pinouts/6809.html

Use your logic probe to see what the CPU is doing.

Thanks. I'm not sure what they are supposed to be, but here is what I have.
1-low 40-high
2-low 39-low
3-high 38-high
4-high 37-high
5-low
6-low
7-high

The rest of the pins that are not listed are ALL floating or no reading. Should this chop be a little more active? Thanks for the patience.
 
After doing some more looking around I noticed there are two transistors missing next to the edge connector. You can see them here on this one, and a few others I have looked at, but they have been removed from mine.
http://zumbrovalley.net/arcade/DoubleDragon/
Also this board did have some work done as the 5.38 crystal has been replaced with a half-ass solder job.
 
Thanks. I'm not sure what they are supposed to be, but here is what I have.
1-low 40-high
2-low 39-low
3-high 38-high
4-high 37-high
5-low
6-low
7-high

The rest of the pins that are not listed are ALL floating or no reading. Should this chop be a little more active? Thanks for the patience.

pin-38 should be pulse, without the clock signal the chip won't function.
Check the crystal and replace the transistors ( C1162)
 
Those two transistors near the edge connector are just for the coin counters, they're not the reason your board is not booting.

If the clock input to the CPU is not toggling, I'd start probing around the clock generation circuit beginning at the inverter at IC56 on the video board, then the LS161's it feeds into, etc. Check out the schematic named "CLK" in the video board schematics.
 
Those two transistors near the edge connector are just for the coin counters, they're not the reason your board is not booting.

If the clock input to the CPU is not toggling, I'd start probing around the clock generation circuit beginning at the inverter at IC56 on the video board, then the LS161's it feeds into, etc. Check out the schematic named "CLK" in the video board schematics.

+1

That clock circuit is like the starter in your car, the board will not start without it, just like the starter in your car.

You can't push start that board but you may be able to push start your car:)
 
If it's not something in the clock circuit that I can't easily find, this may just become a parts board. Schematics for this board are hard to find and the one I did find has lots of Japanese on it. I'm a little too much of a newb in this area to being trying to follow a schematic like the one for this PCB. The crystal is good, I had a spare to replace it with.
 
If it's not something in the clock circuit that I can't easily find, this may just become a parts board. Schematics for this board are hard to find and the one I did find has lots of Japanese on it. I'm a little too much of a newb in this area to being trying to follow a schematic like the one for this PCB. The crystal is good, I had a spare to replace it with.

follow the traces from that crystal to the next chip and use a logic probe to find where it is missing. You have to get that clock going or it will never start up.
 
With your logic probe, see what you have on pin 10 of IC56:

0HzIR.png
 
With your logic probe, see what you have on pin 10 of IC56:

0HzIR.png

Where did you get the schematic schematic set from? I've got a Double Dragon boardset and wouldn't mind keeping decent schematics on hand.

Also, it should be noted that the IC56 you mention is on the second board, not the top one with the CPUs on it. I went looking at my DD board and was like "hey, that crystal isn't 12mhz!" and realized I was looking at the one for the audio section..
 
Where did you get the schematic schematic set from? I've got a Double Dragon boardset and wouldn't mind keeping decent schematics on hand.

http://www.mameworld.info/ubbthread...ews&Number=238772&Forum=All_Forums#Post238772

Pin 10 of IC56 is dead. When I look at the data sheet for that chip, it shows pin 10 as an output. So, should I be trying to follow what leads to that?

If pin 10 is dead (not high or low) I would just go ahead and replace IC56. Out of curiosity, what is pin 11 doing?
 
http://www.mameworld.info/ubbthread...ews&Number=238772&Forum=All_Forums#Post238772



If pin 10 is dead (not high or low) I would just go ahead and replace IC56. Out of curiosity, what is pin 11 doing?

Pins 1,3,6,8 and 13 are the only pins with any activity. I will go ahead and see if I have an extra one of these around and replace.

IC 56 on the board is a MB74S04. What I have been able to find was DM74L04 and SN74S05. Would either of these be compatible to put in there?

I did find a 74LS04.
 
Last edited:
Thanks. I'm not sure what they are supposed to be, but here is what I have.
1-low 40-high
2-low 39-low
3-high 38-high
4-high 37-high
5-low
6-low
7-high

The rest of the pins that are not listed are ALL floating or no reading. Should this chop be a little more active? Thanks for the patience.

check these again now that you have a clock.
 
check these again now that you have a clock.

OK, a little different. What's not marked is also dead or floating. EDIT: I did just notice another 68A09P @ IC49, which kind of confuses me because the schematic above shows IC49 as an LS161.
1-L 40-H
2-L 39-L
3-H 38-H
4-L 37-H
5-H 36-DEAD
6-H 35-LOW PULSE
7-H 34-L
33-DEAD
32-DEAD
31-HIGH PULSE
30-L
29-L
28-HIGH PULSE
27-L
26-L
25-L
24-L
 
Last edited:
Back
Top Bottom