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nnap

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I have a completely dead FH board. When I follow the reset signal I can see it trigger on pin 6 of the TC0220IOC. Based on the schematics that I found, pin 8 should output the reset signal but it stays low. Is the chip shot?
 

Hammy

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Typical problem of a PCB plugged in backwards and toast by the 12V. IOC Chip needs replacement.
The problem with this chip is a lot of dead boards this chip will be toast too.

The way to do it is take one from a good board , and then replace the "good board" missing one with the unknowns from the donors.
OBV the "good board" would not be amazing in case of a mess up.

On this taito you can't swap this IC too many times or the pads will break away from the board.
 

nnap

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thank you for the details. I did lift pin 8 of the custom and routed the reset signal to the pad. That got me some activity in the sound section but still no boot. Looks like some address lines are also going through that custom.
 

caius

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thank you for the details. I did lift pin 8 of the custom and routed the reset signal to the pad. That got me some activity in the sound section but still no boot. Looks like some address lines are also going through that custom.
Sorry but you can't simply by-pass it in this way :) A replacement of the TC0220IOC in on my TO-DO list and I have done some preliminary work, stay tuned!

 
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Hammy

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I have plenty of them on scrap but it's a crapshoot if they work or not, can send you a couple over to try if you like.

a full new replacement would be awesome and would save a lot of time swapping them around to find a good one ;)
 

nnap

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I am happy to take you up on your offer Hammy. Also looking forward to a full replacement from caius :)
 

nnap

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Progress! Switched the IOC out with a known working one and the game boots. Two new issues:

- Music is scratchy and quieter than the sound fx. Replacement DACs are on the way.
- Moving the plane around and shooting, triggers a coin error. Was able to confirm this in the test menu. When multiple inputs are pressed, it can trigger the coin button. Probably the input resistor arrays. Found one that has two pins at 8K ohm instead of 10K ohm. Will replace that one with a known good one to see if that fixes the problem.
 

Hammy

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It was previously plugged in backwards so replace the arrays that are in line with the 12v pin (when jamma is reversed)
 

nnap

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Update on the repair. I desoldered all of the resistor arrays and checked them out of circuit. Two of them were a bit funky. Replaced them and put all of them back. The problem is still there. When I enter the input test menu I can see the strange behaviour. What's quite interesting is the fact that the input remain stuck when I circle the stick in one fluid motion. E.g. I start from top and rotate the stick clockwise. UP, RIGHT, DOWN, LEFT will stay active. When you fool around with the stick and buttons it will occasionally trigger the coin and service switches. From what I can tell this is isolated per player. So wildly moving around the stick and pressing buttons will not trigger any of the P2 inputs.
 

Hammy

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I think it goes to 273(s) next, check all the lines and replace the 273(s).
 
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