Repair Logs – Page 79 – JAMMArcade.net

Haunted Castle repair log #2

Dec 282015

Got this pcb from a friend of mine for a repair

haunted

The pcb had already all the sram chips repaired and some flying wires underneath because of broken traces.

Upon boot up, it constantly reset with this message:

haunted1

First thing was to test the socketed sram chip 6264 near the 2 big customs but as expected they were good.

Tried to flex the pcb and it booted with wrong palette sometimes

haunted2

Surprisingly once it booted it could be played with wrong palette all the time until the next boot.

So the code did only a check at the beginning.

After pressing and flexing everywere I found out that the game booted only when I pressed the Hybrid module 007327

I discovered looking underneath that the module has some small srams and looking at the schematics this is confirmed.

haunted_007327

I turned out that one pin had a subtle loose contact. I reflown brutally everything to make it more resistant against shocks.

haunted3

Booted the game and I was welcomed to a perfectly working game

haunted4

haunted5

Aliens repair log #1

PCB Repair Logs 2 Responses »

Dec 272015

I had on the bench this Aliens PCB:

Aliens_PCB

Board had sever sprites issue:

sprites_issue

I performed a MASK ROM check which reported two bad 4Mbit devices @K2 and @K8:

MASK_ROM_check

I was able to exactly reproduce the issue by using two dummy ROM files in MAME:

0001

So, without further delay, I went to remove these devices and install two 40 pin sockets for the 27C400 EPROM replacements:

sprites_MASK_ROM_rework

With these replacements fitted sprites were perfect but I noticed that sound samples (like voices of main character or enemies) were missing:

Sound samples are stored in a 2Mbit MASK ROM @D5 (which is not checked by the self-test) and its data are processed by a custom marked ‘007232’ which is a PCM controller:

007232&MASK_ROM

Probing the 2Mbit MASK ROM revealed no activity on data and address bus, all pins were stuck high so I removed it:

MASK_ROM@D5_removedJPG

and replaced it with a 27C400 (with doubled content since no 2Mbit MASK ROM replacement exists).This restored all sound samples.End of job.

Rainbow Islands repair log #9

PCB Repair Logs 2 Responses »

Dec 262015

Yes, yet another Rainbow Islands on the bench!

Rainbow_Islands_PCB

Once powered up the board, I was greeted by this static screen:

no_boot

The watchdog was active sign that there were troubles in main code execution.For first I dumped the program ROMs and they were good (although they were from the Extra version so board was actually an hybird since C-CHIP was the one from the normal version).Then I passed to analyze the WORK RAMs (two Toshiba TMM2063) and I found weak signals on data lines of both:

weak_data_lines

This lead me to remove them, they both failed when tested in my programmer:

WORK_RAMs

With good WORK RAMs the board successfully booted but sound was missing at all:

Fitted a missing 1000uF 16V capacitor @C84 in the sound section was not enough to restore sound:

Missing_1000uF16V@C84_

I noticed that the RAM of the Z80 audio CPU was another TMM2063 which seems to be very unreliable part (like Fujitsu TTLs, I’d say..) so I went to piggyback the one @IC44 and sound was restored.The chip failed the out-of-circuit testing:

6264@IC44

Yes, yet another Rainbow Islands PCB saved from scrap pile!

CPS1 A-BOARD (old revision) repair log

PCB Repair Logs Comments Off

Dec 252015

I got this CAPCOM CPS1 A-BOARD (the old hardware revision) from my friend Joachim for a repair:

A-BOARD_OLD_PCB

He said me that board had some input problems.This was confirmed once I powered it up since most of player 1 and 2 controls were irresponsive but, after few times I cycled power, suddenly the board lost the red color:

missing_red

I started to troubleshoot first the input issue.As usual I inspected visuallly the board and found some corrosion near the JAMMA edge, some of the traces from the involved input pins to custom resistor/capacitor arrays and 74LS245 were eaten:

traces_corrosion

This was confimed also using my multimeter in continuity test.With some patching work and jumper wires I restored the connections and after this all controls were correctly working:

patching

As for the red color issue, schematics for this hardware are available so I went to look at the involved circuit:

palette_circuit

I found weak data signals on the two CXK5814 SRAMs (compatible with the TMM2018 suggested by schematics and PCB silkscreening) @4D and 5D (good on left, bad on right) :

data_signal_comparison

Since the data bus is shared between these two chips I could not know which was exactly the bad chip affecting the other so I piggybacked both them and when I did it on the one @5D, the red color was restored.So I desoldered the chip and it failed the test in my programmer:

CXK5814P-45L@5D

Fitted a new SRAM chip fixed the board completely.

Blood Warrior repair log

PCB Repair Logs Comments Off

Dec 192015

Another board from my friend Marco and another quick fix.Got from him this original Kaneko Blood Warrior PCB:

Blood_Warrior_PCB

On power up the board showed the “RAM CHECK OK” message but instead of going into game it was resetting in a endless loop:

missing_boot

Boardset is made of a CPU board and ROM board.Having a Great 1000 Mile Rally which runs on same hardware I could verify that the CPU board was good so the fault was located on the ROM board:

ROM_board

So, I wen to dump the program ROMs and compare them against MAME files.When I tried to read the one @U124 (a 27C010), my programmer reported a bad contact on PIN32 (VCC) and gave me an empty dump:

27C010@U124__

Device was internally damaged so I reprogrammed another one.Once fitted it, the board successfully booted into game without any further issues and I could declare also this board 100% fixed.

fixed

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