Another new day, another PCB repair. An easy and lucky one with a strange epilogue though.Got this original Bionic Commando PCB from Ebay as non working:

When I received the board I noticed a piece of tape on it saying “WON’T BOOT” so I was ready to a static garbage screen or worse, a nice black one.So I powered up the board and I got this instead:

Video had jailbairs all over the screen, gameplay and sounds were OK.So, as usual, before starting my troubleshooting, I made a visual inspection that revealed :

One 74LS367 was missing, another one was cracked and, the icing on the cake, solderside of the video board had a lot of scratches but at the end I found only one broken track that I jumpered with a bit of solder.

So, fitted a new 74LS367 and replaced the cracked one, I was confident about but I was wrong, there was no change at all, jailbars were always present.

So, with the help of the schematics, I started to check everything related to the issue .I dumped the ROMs containing the tiles and they were fine against MAME,  did some in-circuit testing with my B&K 560A IC tester but nothing was wrong in the presumed involved parts of circuit.After some hours of investigations I was giving up when I decided to check the voltages on PCB.I measured +5.1V on a IC so I lowered it a bit but without immediate success.A little frustrated I powered off the board and then after some minutes on again and I got:

I don’t know if this is really related to the voltages (I raised to +5.1 again and jailbars didn’t appear), the fact is I finished the game and no issue occurred again.Oh, I love the soundtrack of 1st level, it reminds me the happy days playing this game on my Commodore 64.Another day spent, another great classic added to my collection…

Bought this PCB (among others) from Ebay as untested/not working:

This, judging from the auction pictures and the GX477 serial, should have been an original Konami Shao-lin’s Road PCB but after dumping the EPROMs it turned to be a Kicker one (the overseas version).Anyway, before powering it up, a visual inspection revealed that one IC was missing:

Now, in absence of any schematics, looking at some PCB pictures on the Net, I figured out the missing IC was a M58725P SRAM pin to pin compatible with a 6116 (or 2016, 2018 etc..).Fitted a socket and a 6116 SRAM, I powered up the board (it uses the Konami Classic pinout, the same used for many other Konami games) and I got this:

These patterns of lines were changing on the screen sign that the board was running fine , infact I could coin-up and hear all the sounds but the video had some issues related to timing signals used to draw display, I presumed.

So, with the fear that one of many custom (with scratched ID) was bad, I started to test the ICs with my HP 10520A logic comparator and logic probe.All was fine until I came across a 74LS74 (location C6) whose ouputs was stuck low.Its data input pin (connected to an output of a 74LS161) had no activity at all but the near via which had to be connected to was pulsing!Infact my multimeter didn’t buzz on this and a closer look revealed this:

Bridged this broken track with a bit of solder, I powerer up the board again and I got:

Board 100% fixed and another classic one preserved!