PCB Repair Logs – Page 14

Outrunners repair log / pinout

Jan 272019

Got this game from a friend who took out the board out of a rusty cabinet.

The game needed badly a clean, so I dismounted everything before attempting to turn it on and washed everything carefully.

The game has two jamma connectors for player 1 ( Monitor A,left connector looking at the above picture) and player 2 ( Monitor B, right connector looking at the above picture). The connectors share same power lines, so you can connect wherever you want to play as P1 or P2.

Unfortunately board was not working correctly, it showed from a brief moment a garbled text about network connection and then nothing happened.

I decided to start dumping the program maskroms and found immediately one branded SEGA MPR-15539 which had some internal connection problems.

The other one , same type and capacity was dumped good.

After burning a new program rom on a 27c400 ( 4mbit maskrom pinout eprom), game booted perfectly although without any sound.

There was not even a noise coming from amplifier so I decided to desolder it and found immediately the problem

The amplifier was litterally blown

From Mame source I could get the right one to order, a TDA1518AQ, replaced it and finally the game had sound.

Unfortunately some tracks sounded bad with wrong samples.

There were other SEGA branded maskroms used as PCM samples, I read both of them ( 16mbit maskroms) and one of them , IC1, had A16 internally broken.

After buring a new 27c160 eprom with IC1 data, game sounded perfectly again.

No other problems were found

I will share the pinout of the board to play it on a different cabinet than the original one with a filter board ( the manual has only the schematics of the filter board unfortunately).

Game is Jamma as stated, so all power, video and audio pins are the same.

Board is using the following digital pins: on component side pin 22 is for shift up and pin 22 for shift down. On solder side, pin 22 is to select DJ Music or radio, pin 22 and pin 23 to move forward or backward the selection of musics. This is valid for both P1 and P2 connectors

There is an AMP connector in the middle used to drive lamps but I haven’t yet figured out the pinout and to me is not very interesting.

The most interesting part is the analogue controls which is handled but the daughter board 837-7636 which is in common with all Sega System 32 driving games.

I found a partial pinout on a japanese website and decided to expand it with Outrunner pinout

Last Duel repair log

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Jan 272019

Bought this game for personal collection but despite having declared working it had some graphic faults.

In particular the intro had blockly graphics and generally lacked shade of colours. The gameplay was in general fine at least for the first two levels.

I started to check maskroms and found LD13 and LD15 which handled the tiles of the intro. Maskroms were tested good on the programmer.

Data pins went to a 86s100 custom chip which usually is not very reliable ( see bottom right of the pic below)

At this point I decided to put a socket and change it with another one I took years ago from Poker Ladies.

Unfortunately the defect was still there but after another look underneath the board and I saw some borken traces which connected the custom to a 74ls273.

There were 3 traces severed but still the graphics were not fixed at all without a sign of improvement.

At this point I started to probe all the other ttl of the video board until I noticed a floating data pin of a 74ls273 which led again to the custom.

The trace interrupted at some point but I could not see any visible scratch until I noticed it near a silscreened text H1, not easy to find at all

After repairing this track the game was fully restored

G.I. Joe double repair log

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Jan 222019

Got from Portugal five faulty G.I. Joe PCBs to repair (hopefully all of them…).I had a good start and could fix two of them.

The first board was in good shape with no missing parts:

It booted into game but colors were completely wrong and most of graphics missing:

I launched a MASK ROMs check which reported all the devices as good so the problem was elsewhere :

I remembered I had a similar issue in some of my past repairs, the culprit was the ‘053251’ custom ASIC which is present on my board too:

The Simpsons repair log #3

This custom takes on input different layers of graphics as well as some priority bits and outputs 11 bit of palette index plus two shadow bits (info taken from MAME source)

I went to replace the IC with no further analysis:

Graphics were completely restored and board perfectly working with no other issue :

The second board was in good shape and complete too :

But it booted to a static pink screen :

Also in this case my suspicions fell on the ‘053251’ custom ASIC :

I replaced it, it was really faulty.Now the board tried to boot but failed the power on self-test:

The bad reported devices were all part of the sound circuit : @7C (SOUND ROM), 6C (SOUND RAM), @3E (‘054539’), @2D (62256 SRAM)

The sound CPU is a Z80B, probing it revealed floating address/data lines:

Luckily the CPU was aready socketed so I swapped in a good known one (a Z80E with clock up to 8MHz)

The board got now past of the self-test and booted into game but sound was absent:

Obvioulsy the culprit was always him, the ‘infamous’ ‘054986A’ hybrid module:

As I usally do, I removed it :

and installed proper sockets:

Then I serviced the audio module replacing the OP-AMP underneath :

and electroytic capacitors on top:

Sound was fully restored and double repair accomplished.

Gundhara repair log #2

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Jan 182019

Received from Germany this Gundhara PCB, a top-down shooting game released in 1995 by Banpresto:

According to the owner the PCB suddenly developed a graphical issue.When I powered it up I could actually see some colors problem, the BLUE one was ‘bleeding’ in some parts of graphics:

After a quick check on PCB I could figure out the palette circuit made of two 6264 (8K x 8-bit) SRAMs, a custom (S-DIP 42 pin) marked ‘X1-007’ (which probably contains some latches or flip-flops) and three SIL resistor arrays configured as R-2R ladder to perform the final conversion from digital to analog (DAC)

When I probed the two 6264 SRAMs I found weak signals on some data lines of the one @U39, here is a capture from scope comparing the signal with an heathy one :

Sure enough I desoldered the chip, it indeed failed the out-of-circuit testing :

Installing a good chip fixed the issue, board 100% working again.Job done.

Guardians / Denjinmakai II repair log

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Jan 142019

Received today from Germany this Guardians PCB, also known as Denjinmakai II, a horizontally-scrolling beat-em-up released by Banpresto in 1995)

According to the owner the game played totally ‘bind’.I could confirm it as soon as I powered the board up :

Board playing ‘blind’

But, as you can see from above video, I was able to restore some graphics by pressing down this surface mounted custom ASIC (QFP 208 pins)

Judging from the heatsink on its top this custom ASIC acts as a GPU generating most of the graphics and video signals too.At a closer inspection I found many lifted pins on all four sides.An example :

I promptly reflowed the IC, this gave me a steady picture but all the graphics were scrambled and, judging from the blueish screen, the RED color was missing too :

Looking at solder side of the PCB I noticed a long and quite deep scratch passing across some traces:

Inspecting the area with a microscope and doing a continuity check with my multimeter confirmed that some traces were severed and other caused unstable contact:

I patched and reinforced the traces with some AWG30 wire :

This lead to few improvements, graphics were still scrambled so I moved on to troubleshoot the lack of RED color.This was pretty easy to fix as the board had a quite clear damage that broke the trace which carries the signal to JAMMA edge connector :

As for bad graphics, I decided to double-check the previously reflowed custom ASIC and found a solder bridge shorting two pins:

Removing it fixed the issue and board completely.Repair accomplished.

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