Crossbow Boardset DOA

Takeman

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I have a crossbow boardset that was working all the way but suddenly went DOA. The orignal power supply was rebuilt and appears to have all the correct voltages. There appears to be power to both boards, but I get absolutely nothing on the screen and it does not coin. I also do not have coin door lights which look like they are powered from the board. Any ideas?
 
I have a crossbow boardset that was working all the way but suddenly went DOA. The orignal power supply was rebuilt and appears to have all the correct voltages. There appears to be power to both boards, but I get absolutely nothing on the screen and it does not coin. I also do not have coin door lights which look like they are powered from the board. Any ideas?

I think you need to double check the voltages at the board. Check Pin 7 of the CPU (at 1H) and make sure it's at least +5V. If it's lower or over 5.5V, then you might have an issue.

If you have a logic probe, you can check to see if there is any activity on the CPU on pins 8 through 23. If you're not getting activity, you might have a bad CPU, if you are getting activity, then the CPU is probably good and something else is causing the board to not work.
 
I checked pin 7 and have 5.3vdc. I checked with a logic probe and pins 8-23 apprear to be all stuck high, no activity. I replaced the CPU with an NOS one and got the same result.
Any other ideas on what to check?
 
I checked pin 7 and have 5.3vdc. I checked with a logic probe and pins 8-23 apprear to be all stuck high, no activity. I replaced the CPU with an NOS one and got the same result.
Any other ideas on what to check?

If you can adjust the 5V down a bit lower, try that. 5.3 is a little on the high side.

Then check pins 2,3,4, 32, 37 and 40 on the CPU, are any of those stuck High?

Pin 32 is the R/W and should show activity as well.

If Pin 37 is, check 2J and 1K.

If Pin 40 is stuck High, that's the HALT and you should check the resistor at R6.

It could also be a bad crystal.
 
I adjusted to +5.3 down to +5.01, no change. All those pins on the CPU are stuck high.
I changed out the crystal & R6, no change. 2J & 1K seem to be stuck high as well. Not sure what else to do.....
 
I adjusted to +5.3 down to +5.01, no change. All those pins on the CPU are stuck high.
I changed out the crystal & R6, no change. 2J & 1K seem to be stuck high as well. Not sure what else to do.....

Ok, for 2J, check pins 9 and 8, and 11 and 10. If 8 is high, 9 should be low. If 10 is high, 11 should be low.

You should also inspect the board for bent pins that might be touching another pin or touching ground.
 
On 2J, they are all high.
The boardset was working for the past year, mounted in the cabinet. Went to turn it on and got zip. So there should not be anything bent. I did not see anything that looked bent or otherwise suspicious.
 
If no light on door, but voltage checks everywhere.. see if you lost a ground.

Kevin

There seems to be power throughout both boards and the KK connector and headers have continuity between the boards. I also replaced the ribbon cable..still nothing. This has got to be something stupid as it was working perfectly....
 
My point exactly :) If you are getting voltage everywhere.. it may lost ground. Manual ground your light and see if it comes on. If it does, then start checking ground for break.


Kevin


There seems to be power throughout both boards and the KK connector and headers have continuity between the boards. I also replaced the ribbon cable..still nothing. This has got to be something stupid as it was working perfectly....
 
My point exactly :) If you are getting voltage everywhere.. it may lost ground. Manual ground your light and see if it comes on. If it does, then start checking ground for break.


Kevin


Ok, so Kevin you made sense. I pulled the board out and double checked the header pin connection between boards. It seemed flaky to me as I had to puch pretty hard on some of the ground pins to make contact. Looked like it was intermittent. So I removed the original connectors, made a ribbon cable for the main and repalced the 10pin header on the sound board. Plugged it all together, continuity was good. Popped it in my Crossbow and it came right up. So Kudos for Kev for thinking of that.......

Brien, thanks for your help too..I'm just a retard :p

-Troy
 
Ok, so Kevin you made sense. I pulled the board out and double checked the header pin connection between boards. It seemed flaky to me as I had to puch pretty hard on some of the ground pins to make contact. Looked like it was intermittent. So I removed the original connectors, made a ribbon cable for the main and repalced the 10pin header on the sound board. Plugged it all together, continuity was good. Popped it in my Crossbow and it came right up. So Kudos for Kev for thinking of that.......

Brien, thanks for your help too..I'm just a retard :p

-Troy

No problem, I'm still learning this stuff too. Kevin knows a lot more about this stuff then I do :D

Glad you got it working.
 
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