In first repair the issue was due a faulty ‘VS8905’ sprites address generator (there are two of them on PCB)
When I put my fingers on the one @U115 (same location of the faulty one in previous repair) it was quite hot, this was a clear sign that internal junctions were bad and a proof that this part is prone to failure.I removed and replaced it:
My board was faulty since it was sitting after performing the SELF-TEST without reporting any error :
First of all I swapped a good motherboard but this didn’t lead to any improvement so the fault was located on VIDEO board.At a closer inspection I found some scratches on solderside of this board:
One trace was really severed, it was the one connected to pin 9 of the KEY custom ‘176’.Problem was caused due the board has been crushed under some weight hence solder sides of the two boards were touching and scratching each other:
After patched the trace, the board successfully entered in game but I could not coin up.I quickly pinpointed this fault to a missing ‘CUS95’ resistor array @1K near the JAMMA edge:
Recently I’ve been working on some Windows based software to use the Data I/O 29 series programmers.
Its coming along well and I have a few people willing to test things out for me which has been great as its a pretty tedious task of trying things out and reporting back, rinse and repeat.
I captured a small video showing some progress.
The programmer itself isn’t all that hard to interface with as most of it is just issuing commands which are all outlined in the manual but there are a couple of things to deal with when it comes to uploading a file to the programmer.
I’ve also been collecting ID codes for programmers and modules so I can auto detect programmer and more importantly the module that is fitted. This allows me to auto populate a device list.
Ive tested this using a cheap USB to serial adapter and its been working fine.
As many of us know (not only long term arcade collectors/enthusiasts) Toaplan manufactured few but excellent games.Some of them can be considered real masterpieces like Out Zone and Truxton for example.Going into technical details four of them are united by the fact the hardware uses a custom IC to handle inputs: the ‘HK-1000’.I have partially covered this argument in my past repair log of Tatsujin Oh, you can read it here:
As said in the above post, two revisions of the HK-1000 were made with same functionality but different package.The first one was ceramic hence very fragile.This is used on Truxton II/Tatsujin Oh and FixEight:
The second one is more robust and it’s adopted on Ghox and Pipis & Bibis :
If this custom goes bad (like it happens very often especially on first revision) you will be no longer able to fully control the two players and in the worst of cases the board will be stuck on a TILT message.The only option could be find a donor board but we are speaking of valuable PCBs even if faulty.So some kind of replacement was needed.
There is very few info and documentation about this custom but it seems Toaplan engineers embedded on a single IC (the HK-1000, indeed) all the circutry they used to handle inputs (but also coin counters/lockouts) on previous PCBs (Wardner, Out Zone, Rally Bike and others too).I took inspiration from an Out Zone PCB to study the design:
As you can see from the above picture, I highlighted two sections of PCB : the blue one concerns the circuitry for coin counters/lockouts handling, the red one is for inputs (players direction and buttons, TEST, SERVICE, TILT).With this knowledge I started my tests.As testing platform I used a Pipis & Bibis PCB (the cheapest one which carries the HK-1000).I removed the custom and mapped some inputs following the above mentioned design:
This was successful so I started to draw and route schematics for a real replacement.I voluntarily omitted from my design the circuitry for coin counters/lockouts as it’s not a vital part (although I figured it out so I can implement it in a later moment).I sent the layout to a manufacturer and after few days I received the bare PCBs:
Very few components are needed to populate the PCB :
Three 74LS240 in SOIC20 package
Three 100nF ceramic by-pass capacitors in ‘0805’ package
Three (two 9 pins and one 8 pins) 4.7Kohm SIL bussed resistor networks for inputs pull-up (I opted for thru-hole ones to keep cost down, they can be salveaged from arcade PCBs)
Two strips of 24 pins male rounded machine-tooled pin header with 2.54mm of pitch.The corresponding female ones must be used on the arcade PCB.
Here is final result after 5 minutes of soldering:
A comparison with original custom:
Testing on the Pipis & Bibis PCB was successful, all inputs of both players were correctly mapped and working as well as TEST, TILT and SERVICE ones:
As said, this is not a 1:1 reproduction of original part since coin counters/lockouts handling has been not implemented for now but it’s enough to salveage your faulty boards from uselessness.Stay tuned for the next reproduction project!
