Sega System 1 PAL update

 PAL Updates  Comments Off on Sega System 1 PAL update
May 072016
 

Today we have some new PAL dumps from Sega System 1 hardware.

Thanks to the work of ‘Tirino73’ and ‘f205v’ :

https://www.citylan.it/wiki/index.php/Wonder_Boy_(set_3_bootleg_2)

we have dump of the unsecured PAL16R4 @IC 67, I converted it to GAL16V8 and successfully tested on my bootleg boards.Silvio Grazini confirmed that it works also on original hardware.So now set is complete along with the dump of the other PAL16R4 @IC41 already in our database.

Besides, they dumped also the devices (a PAL16L8 and a PAL16R4) on the piggyback  board, I converted them to GAL16V8 and successfully tested on my boards.

Thanks again to them all.

 Posted by at 10:15 am

1941 : Counter Attack repair log #1

 General, PCB Repair Logs  3 Responses »
Apr 252016
 

I had on the bench this mint 1941 : Counter Attack CPS1 boardset:

1941_Counter_Attack_PCB

Board played fine except for a minor sprite issue on some objects on backgrounds which manifested only on first level:

sprite_issue

The game use the ‘CPS-B-05’ ASIC on C-BOARD which acts as a GPU generating all the graphics:

CPS-B-05_C-BOARD

so I swapped a good known one from a Street Fighter II : The World Warrior boardset:

CPS-B-05_C-BOARD_SFII

All the sprites were restored so I had confirm the ‘CPS-B-05’ ASIC was bad (probably an address line was ‘spitting out’ wrong address).I could swap the entire C-BOARD but appearances count too so I decided to transplant only the IC on the original C-BOARD.

CPS-B-05_SF2_removed

I used an hot-air rework station covering the plastic connectors with tin foil as protection against heat:

CPS-B-05_reworking

To solder the chip I used the ‘drag soldering’ technique:

I succesfully tested the reworked C-BOARD and declared board as 100% working :

 

 Posted by at 6:51 pm

Hammerin’ Harry (Irem M81) PAL dump added

 PAL Updates  Comments Off on Hammerin’ Harry (Irem M81) PAL dump added
Apr 252016
 

Today ‘frsj8112′ from Arcade Otaku forums sent in dump of the specific PAL @7D from an Hammerin’ Harry PCB (Irem M81 hardware).Dump has been successfully tested by him on a GAL16V8 targeting device.Thank to ‘frsj8112’ for his contribution.

 Posted by at 1:52 pm

Undercover Cops repair log #2

 PCB Repair Logs  Comments Off on Undercover Cops repair log #2
Apr 242016
 

Recently I received this Undercover Cops PCB for a repair:

Undercover_Cops_PCB

Before power it up I inspected the board and found that the resistor array @RA3 was replaced by an homemade one, very ugly solution:

resistor_array_RA3

Since the original part is not a common resistor array (it’s a mix between 4.7KOhm and 220 Ohm resistors) I replaced it with an original spare part :

4.7K_resistor_arrays

Powering up the board, all was working fine except for the PCM samples that were scratchy:

The chip which plays the samples (fetching data from a MASK ROM located on VIDEO board) is the ‘GA20’ ASIC:

GA20

Probing some pins with an external amplifier I had confirm that sound came out already corrupted from it so most likely its DAC section was faulty. So I played the card of replacing it taking a good chip from a GunForce donor PCB:

GA20_removed

And this was the winning move since voice samples were restored:

 Posted by at 12:02 am
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