View Full Version : Irem 'Kung Fu Master' Repair Log

31st May 2009, 03:27 AM
Symptom: Graphics very garbled, no more than character blocks with miscellaneous bits and pieces in them. Sprites can sometime be made out and the main area scrolls as it should as the game does play
Cure: Bad outputs on the LS367 at location 5F on the middle board

Symptom: Some bits not flipping on DIP switch 1
Cure: DIP switch was okay, some bad outputs on the LS367 at location 1B on the middle board

Note: both affected chips were made by Fujitsu (a common point of failure on boards of this era (1984))

31st May 2009, 11:14 AM
Note: both affected chips were made by Fujitsu (a common point of failure on boards of this era (1984))

No doubt Arcade King will agree here :D

Some say the "F" on those chips stand for something other than "fairchild".

While yeah they are dieing, 13+ years is a good innings and something I doubt they would have picked up in QA (Hey our IC dies after 13 years, whereas our competitors are getting 20+ :lol )

Thanks for the logs, I find them both interesting and useful.


31st May 2009, 12:23 PM
F chips are a common failure on any board of any vintage it seems, well the TTLs are - the F SRAMs are pretty good - never met a dead one of those, but have just brought my Psycho Soliders board back to life by replacing 4 Fs :rolleyes

31st May 2009, 07:11 PM
I sometimes wonder if it's worth replacing ALL the Fujitsus on a board where they are known to be failing, but it's a little daunting if there are more than a dozen or so and even then there is of course no guarantee that such an action wouldn't prevent other ICs from failing. Even if the Fujitsus are failing, the remaining ones could of course still last for a few more years.

Arcade King
31st May 2009, 07:25 PM
Yeah I'm pretty lazy. I know by changing out the all F chips on my TMNT(or any other board loaded with F chips) boards will make them rock solid but its just very time consuming.

31st May 2009, 07:31 PM
I wouldn't call you lazy at all for not swapping them all out, especially as they could well last for years yet and in the meantime other non-Fujitsu parts might fail. Okay, if there were less than half a dozen it might be worth doing and if others of the same type were also failing, but if not - well, is it worth it?

Arcade King
31st May 2009, 07:34 PM
I always find if one type goes say 74ls74 the lot will fail. like they have some sort of self destruct built in.

31st May 2009, 07:39 PM
I've found the same in many cases. But when there are loads of the same chip on the board that are currently working ............ well, what to do? :)

31st May 2009, 08:23 PM
I have considered it, but with my Psycho Soldier board I reckon there would be upwards of 250 F chips on it, and as I would get the replacements off other boards I would have to desolder all the replacements from elsewhere. Replacing 500 chips is a prospect that scares me. If I could wave a magic wand and get someone else to replace the lot with Hitachi chips I would certainly wave it!

31st May 2009, 08:26 PM
I know exactly what you mean! :)