Porchy

Kicker (Shao-lin’s road) (bootleg) repair log

PCB Repair Logs Comments Off

Oct 072018

Earlier this year I attended a meetup at UKVAC user Bonehead’s house.
One of the things I brought back with me was an unknown bootleg PCB that a was being given away.
I opted to take this particular PCB because it was 6809 based and I needed something to help me continue work on my Fluke 90 PC software that I started quite some time ago.

This PCB uses the Konami Classic pinout for which I already have an adapter for so following a quick visual check I plugged this in and powered up.

As you can see we have watchdogging going on.
Right next to the 6809 there are two 74LS244 buffer IC’s. A quick continuity check showed that these were connected to the address pins of the 6809.

Probing the 244 at E8 showed that all the outputs were dead. Removing this revealed a broken trace.

At some point in its life there has been a sort here.
I patched the break and fitted a socket and new 244 buffer and checked for shorts before retesting.

Powered up and all was well again.

Confirmed later that the sound is present too and controls are all working.
A quick fix this time.

1Mbit EPROM Confusion – JEDEC VS non-JEDEC

Technical Info Comments Off

Sep 232018

I’m unsure where this all started and who was the first to break the tradition but when it came to the 32 pin 1Mbit EPROM some manufacturers went rogue.
The difference between a JEDEC pinout and a non-JEDEC pinout is two pins swapped. The signals in question are /OE and A16 and the pins are pin 2 and pin 24.

Check out this picture for a visual description

Normally this information would be all we need to know. For example Macronix has the MX27C1000 eprom which has a JEDEC pinout. They also have the MX27C1001 which has a non-JEDEC pinout.
So far so good.

The confusion starts to creep in if you wanted to replace a Macronix MX27C1000 EPROM with say Sony’s CXK27C1000.
Its a natural assumption to make that these two are going to pin compatible but that is where we would be wrong.
Sony’s CXK27C1001 is actually the JEDEC pinout and the CXK27C1000 is the non-JEDEC pinout.

I believe that all manufacturers of the 27C010 use the JEDEC standard pinout.

Here is a table that we have put together that hopefully captures all the variants and their pinout type.

So if your replacing an EPROM of this type then make sure the EPROM you have is the correct pinout or your going to get problems.

Thanks to Caius and Simonden for their help putting the list together.

Black Tiger repair log #3

PCB Repair Logs Comments Off

Jul 012018

Although this is a bootleg it follows the original PCB closely.
Couple of easy fixes on this one.
First a character issue and second a sound issue.

As you can see in the video above, the screen is filled with “A”s and none of the text is correct

There is a seperate EPROM used for characters on this game.

Pulling this and reading back with my programmer yielded a valid dump for Black Tiger.
Checking the adjacent associated 74LS273’s and 74LS245 showed I had at least one pin floating.
I traced this back to a nearby TMM2016 which had D7 floating.

Replacing this fixed the screen

The sound issue was even easier. The sound program EPROM was completely smashed. Replacing it fixed the issue.

Job done.

Taito MB112S146 custom reproduction

Reproductions Comments Off

Jun 122018

Recently I have been working on reproducing the MB112S146 custom chip for my friend BanjoGuyOllie.
This module is found on Arkanoid, Darius and probably some other titles too.
This has now been done and is available in the downloads section. It required the adapter board from ColinD but I will soon compile for MikeJ’s module too.
So far its only tested on Arkanoid but probably will never get a chance to test on other hardware.

PLD Archive news

General Comments Off

Jun 102018

The PLD Archive is currently in the process of being moved to a new wiki.
There may be a delay is adding new files while the wiki get populated. This is currently over half way done but the process is long and tedious bear with us.
In addition to the normal PLD files there is also scope to add more detail and pictures so if anyone has any good quality PCB pictures or extra information like missing PLD IC location details or names then please let us know.

The old table will be kept up for now until we are sure all the detail has been moved over correctly.
You can take a look at the wiki at
https://www.jammarcade.net/wiki

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