PCB Repair Logs – Page 74

Rainbow Islands repair log #9

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

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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

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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

Cybattler repair log

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Dec 182015

My friend Marco sent me this Jaleco Cybattler PCB for a repair:

Cybattler_PCB

PCB was really in mint condition but when I powered it up I got this:

A blank screen and then the dark.First thing to do in this case is to analyze the main CPU, a 68000 on this board.The CPU was resetting properly but after few second /RESET pin was going from high to stay low, at same time also /HALT line was stuck in this logical state.This was a clearly sign of troubles with main code execution so I went to dump the two program ROMs (27C2001 devices) :

program_ROMs

When I tried to read the one marked ‘2’ @IC53 my programmer warned me about a problem on PIN32 (VCC), ignoring this obviously resulted in an empty dump :

ROM2_27C001@IC53

I programmed a new 27C2001 device and board booted properly but all the background graphics was missing or blocky:

bad_BG

Background graphics data are stored in two 4Mbit MASK ROMs (27C040 compatible) so I went to dump them and resulting files were good.But this didn’t convinced me so I analyzed them with my logic probe and I found that the one @IC67 had all data lines silent :

4Mbit_MASK_ROM@IC67

When I put my finger on the solderside of this MASK ROM I could restore the graphics :

restored_BG

I programmed the 27C040 EPROM as replacement of this bad MASK ROM using the MAME ROM set file and this fixed the board completely.End of job.

Out Zone repair log #2

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Dec 162015

I got this Toaplan Out Zone PCB for a repair:

Out_Zone_PCB

When I powered it up I was greeted by this screen:

object_RAM_error

This kind of error doesn’t necessarily imply that a RAM chip is faulty but also that it can’t be “reached” from the device which wants to read/write it.In this particular hardware the device in question is a custom ASIC sprites generator marked “FCU-2” also used in other Toaplan games:

FCU-2_ASIC

I went to inspect it and found some lifted pins:

FCU-2_lifted_pins

Blocking the PCB with a vise, I did a reflow of the involved pins FCU-2_reworking

100% fixed!

fixed

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