PCB Repair Logs – Page 108

Jumping repair log #1

Jan 042012

Got this Rainbow Islands bootleg yesterday.
The game worked when I tested but was told about a dodgy ribbon connector before buying it so decided to take a look. Not sure what happened after that but the board refused to boot.
After finding a few stuck address lines I decided to check the program ROM’s. Found 3 that would not read properly so I replaced them.
In MAME it lists 2 of the program ROMs as being from the genuine Rainbow Islands set but these are double the size so needed to be split into 2 files and burned to 27512 EPROMs.

Probably worth mentioning that if you use the older 2005 ROMIdent program then the dumps from Jumping actually show up as 2 separate ROMs. Must have been like this at one time.
Booting up now gives me a screen of garbage

Every now and then I could make out a “SCREEN RAM ERROR” message. The screen RAM is located on the second board and suspected this is what happens when the ribbon connector got a bit wrong but couldnt get the game to boot again no matter what I did so I decided to socket the 68000 cpu and see what was going on, kinda wish I hadnt now as I got this

Accepting the error just kept flagging more “tied bits” errors. Turns out this was a red herring as these lines are controlled by a PAL20L8 chip and everything passes if this is removed. Wasted a little bit of time on this.

After taking a careful look at the connector it turns out the plastic housing that holds the ribbon cable in place was damaged and this allowed the ribbon cable to come away from the pins. I properly reseated the cable and tested, the board now fires up in all its crazy bootleg glory

The game plays pretty much like Rainbow Islands does but some of the sprites and names are different and I think the secret rooms don’t work too well.

This game has 3 PAL chips on it, unfortunately all are security locked and I am only able to read 1 of them (might be able to read the one on the video board but never tried).

Pocket Gal bootleg repair log

Nov 212011

Another decent fella from a forum was giving this board away for the price of postage.

Its been a bit quiet lately on the repair front so thought id give myself something to do. Ended up being a really quick and easy fix.
The game booted up and all the sound appeared to be there, it would even coin up but the game could not be started.

Checked pin 17 at the edge connector (Start button) and this was HIGH and it toggled LOW when the start button was pressed. Traced this through to a nearby 74LS245.
The direction pin (1) was held low connected to ground and because the ENABLE pin was pulsing it was pretty difficult to see if the inputs on the B side of the Bus were making any difference to the A side outputs. I piggybacked a new 245 onto it and the game could now be played. I desoldered it and replaced the chip, all is now working. Shame the game is utter crap!

I also took the opportunity to dump the unprotected PAL16L8. I’ve converted it to GAL and tested it. There is a PAL16R6 on there too which ill get around to doing sometime but the board is of typical bootleg quality and a bit of a pain.

Block Block repair log

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Aug 282011

Had this board for ages and never bothered with it.
A guy recently asked me to check out the PAL dumps for Block Block but due to my board being broken Ive never been able to test so I thought id try and repair mine.

As you can see, the board looks a state

There is a suicide battery on these boards that is certainly dead. I removed this and went over to The Dead Battery Society and downloaded the desuicided ROMs.
After burning the two 27c020’s and a 27c512 and following the guide steps I got nothing but a black screen.
I removed the Kabuki CPU and replaced it with a standard Z80.
Now I get the RAM tests and they all pass OK then goes to a blank screen.

After a bit of head stratching I relised that the 27c020 is JEDEC compliant yet the 27c301’s that the board expects are not.
Time for a bit of modding.

I lifted pins 2, 24 and 30 on both 020’s and pins 1 and 22 on the 27c512.
I ran a link from pin 21 of the Z80 pin 24 of both 020’s and pin 22 of the 512. This is the /OE line.
I ran a link from pin 60 of the DL-020F-108U custom IC to pin 2 of both 020’s. This is the A16 line.
Link pin 30 from both 020’s to pin 1 of the 512 then link them all to pin 27 of the Z80 CPU. This is the A17 line.

That should not be complete and the game should boot.
I was able to test both the PAL dumps I have made now and they both work.

There is no sound on my board and it looks as though most of the sound circuit is rotton so wont be trying to repair that. Its a nice game but I have no interest in it at all.

Silent Scope repair log

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Jul 112011

Bought a Silent Scope PCB recently.
It had the “Hardware Error 11P” fault which is known to be cause by the battery failing in the TimeKeeper RAM.
Since the contents of these RAMs are in MAME I thought id fix one up which was probably a stupid idea as I dont have the setup to actually use it, but at least I know I can fix these now.

To get this thing booted up I modified my ATX power supply that I had previously modded to run my NAOMI setup. The power connection are labelled in the picture.

I had to run the VGA output through a standards converter too, it must be 31kHz. Once it was all fired up I was greeted to the startup procedure which consists of what look like RAM/ROM checks. All these passed but then it just hangs on the fault screen for a bit then resets.

The TimeKeeper RAM is located on the top board of a 3 board stack.

I removed the board and set to work desoldering the old RAM chip. It went smoothly considering it had the signature Konami thin traces and small through holes, the RAM just dropped out.

Thought it best to fit a socket in case of any problems with it in the future.
As this version shows up as v1.20, the RAM dump needed if from set UAB.
I did try reprogramming the original but it didn’t hold the data.
After fitting the new RAM the game booted to the test menu.

After working my way through the menus using the pins on the I/O board I was able to finally fire the game up.

So, I have verified that the sound works, the game boots and the digital inputs are working. I have no reason to believe that the rifle wouldn’t work if connected.

UPDATE (06/07/2015):
If you have an Arduino and fancy testing out my Timekeeper programmer ‘sketch’ then you can download it from the Downloads section.
It worked for me but I make no promises it will work for you. Its a basic proof of concept and could do with being developed.

Robocop repair log #1

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Jun 152011

Bought a Robocop board from the AO forums. Seller says the jump button didn’t work.
Doing a visual inspection revealed a burnt out track just off pin 23 on the edge connector, which is button 2, in this case, the jump button.

I repaired the trace but still no joy with getting the controls back.
Further inspection showed that the custom resistor array had burnt out. This resistor array has some modified characteristics compared a normal array, it passes an input out to a different pin and has a few other differences too. As I don’t have any spares of the custom array I decided to use a standard one pulled from a scrap board.

To make this work I had to short pins 6 and 7 together and 8 and 9 together. These are for button 1 and button 2.
The board is now fully working but ill keep an eye out for an original replacement part to fit.

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