Today some addition to our PAL database.With courtesy of user ‘tinhead’ on the EEVBlog forums we can host his recreations of registered PLDs found inside the Hi-Lo Systems ALL-07A EPROM programmer (which I personally use).You can read more about here:
Speaking about arcade PLDs, I successfully reversed into a GAL18V10 targeting device the dump made by Porchy from the PLS153 marked ‘315-5298’ found on some Sega System16B ROM boards (171-570 and 171-5521).
I had this rare Irem Ken-Go PCB (an undumped version included in latest MAME release) from my friend Joachim for a repair:
The board played fine except for an issue where all sprites were formed but missing all colors appearing like black shape:
Sprites generation circuit is located on top board where some customs lie:
Documentation for this specific game was not available but luckily I could know function of the various customs by looking at the R-Type schematics and so identity the one involved in the sprites palette generation:
The custom itself was marked ‘KNA91H014’ in 60 pins QFP package:
Probing it revelead that inputs were fine but outputs had irregular signals:
So I opted for replacing this custom (taking a good one from a dead Vigilante board) :
This was the right move since sprites were correcly restored:
When I powered it up for first time, two were the faults I noticed : sound and sprites were missing.So I started to troubleshoot first issue.The sound circuitry of this hardware is made of an Z80 CPU,a 6116 SRAM, a 27256 ROM and YM3812 DAC plus a couple of custom for PCM samples and music generation (K007232 and ‘K051649’).When I went to probe the Z80, I found that most of data lines were stuck LOW or HIGH.The ROM containing sound code was good as well as the relative RAM.With the help of schematics I figured out that sound code data were latched by a 74LS374 @G11 :
Probing its outpus revealed they were stuck and piggybacking it caused playing some random samples.So I decided to remove the IC :
It failed when tested in my programmer:
Sound was fine but, as I said, sprites were missing (except for some):
Since I already repaired in the past a couple of Haunted Castle boards with identical issue, I knew where to look at.Hardware uses for sprites and tiles some 4464 DRAMs in ZIP package.In particular the two related to sprites are the ones @H3 and @H4:
So I ordered some spare parts from China.When they finally arrived , I could successfully finish my job by replacing them:
PCB Repair LogsComments Off on Capcom CPS-B-01 C-BOARD repair log
Nov032015
Just a quick (but quite important) fix.Got from my friend Josef this spare Capcom C-BOARD with CPS-B-01 ASIC on it:
Whatever game I tried with it, I got sprites issues.Strider for example:
I was pretty sure the CPS-B-01 ASIC was bad, it’s very prone to failure IC but I decided to have a look at it.Doing a continuity test with my multimeter on solderside of the C-BOARD I found two broken traces:
PAL UpdatesComments Off on SEGA Mega Play PAL dumps added
Nov022015
Today, after repairing it, I dumped the PALs from a Sega Mega Play PCB.There were six devices, I was able to reverse three of them, one was already dumped by Porchy from a Mega Tech PCB.The remaining two use latches so a deeper analysis is required.
