PCB Repair Logs Gallag

Gallag (Galaga Bootleg)

Gallag (Galag Bootleg)

PCB Image	Reserved
Pin Out	Reserved

Repairer: Arcade King
Forum Thread: Gallag (Galaga Bootleg) PCB Repair

Love these boards to bits I've had 3 of them plus a alt board which I will post here I got off a mate. They are quite popular because they have no custom chips, easy to reprogramed to the NAMCO or Midway set and are well made. Only down side is they use common TTL chips to replace the custom ones of the original which makes them a BIG 2 layer board.

I'll split the CPU and Video boards in separate posts

Gallag CPU PCB

This is the one I bought from E-bay it was listed as:

QUOTE: "this galaga board is untested. I doubt very much it will work. I have had it in storage for a while so its a 99% it will not work otherwise i would have used it long ago. I dont have the time in the day to be bother to check to see which layer is good and which one is bad. This board is probably best left for parts to get another galaga working. Happy bidding people."

Well he was honest.

Even in the picture in the listing I could see the CPU sync bus controller was tuned around the wrong way and sure enough when I got the board it was and all IC's on it had been completely fried.

This board was a mess, when I first tried to fire it up nothing came up. I felt the top of the IC's and 2 were VERY hot so I quickly turned it off.

Going over the board I looked for anything that could cause a short so use my multimeter and did a continuity between the ground and +5 volt and there was a short to be sure.

The best and easiest way to locate all the effected chips was to one end of the multimeter on the +5 volt and test each pin on every IC. When I found one I would then switch to the ground finger on the pcbs edge connector to make sure there was a short.

I found 16 IC's which follows:

74ls244 @ C10, H3, K3
74ls374 @ D10, E10, F10
74ls373 @ H2, K2
74ls138 @ A1
74ls158 @ L2
74ls259 @ N3
74ls368 @ P5
74ls107 @ N5
74ls28 @ N6
74ls367@ B1,C1

There were other IC's that appeared to be shorted but some of their pins were grounded already so I left them for now.

Using my little Ms Pacman board I tested the Z80's and rams. 2 Z80s were bad but the rams were all ok even the 7489's. 3 roms were bad @ K4, J4 and E5.

Ok after many hours I replaced all the bad IC's and even had to pinch a few rare ones like the 74ls28 and stripped a stuffed pac board for the others IE 74ls259, 74ls368.

Problem: Turned her on and she was alive with zeros all over the screen.
Fix: 74ls367-can't remember which one.

Problem: Game would boot up and hang on RAM OK. A common fault with these boards. If you turn voltage right up board would run, turning it down again would stop on RAM OK.
Fix: This is where a Scope would have come in handy. Problem was another 74ls367 considering most of these chips were already in sockets towards the top I replaced them all to be safe. Board works perfect!

Galaga (Code named Spike)

Pic 2 Added some other amusing pics from the guy I bought this from who got it from a well known tech , those who know the history of this board will know what im on about

Chips found faulty via testing on working board were. 2 CPUs one of which had red dot on it and both the Tri State Proms.

Problem: Dead board....really really DEAD!
Fix: bad 74ls161@7L and 7M Took ages to find but a 74ls00@N7 got the board firing up. stuck output pins 8 and 13.
Bad chips found after board fired up.
74ls32@A4 output stuck low pin 13
Problem: Board boots up then hangs on RAM OK
Fix: common fault with these Gallags, bad 74ls367@H1
Problem: Board boots up gets to the Ram ok, Rom ok, upright etc screen then resets.
Fix: Seems to be another common fault on these boards.
74ls244 @ C10
74ls374 @ D10, E10, F10
Problem: Hard one to find this. Board boots up then hangs at the ram ok rom ok screen and wont advance to the cross hatch.
Fix: Bad 74ls138@J7 all the outputs at pins 1 through to 8 were High with no data flowing.
Syncbus controller had been put in the wrong way and as a result all chips except a 74ls02 were fried.
Forgot to mention I knew the sync bus controller was stuffed and was using my pacman one to fix teh board. Left it last to fix.

Board is now fixed other than need to replace a few bad sockets. Need the two missing Tri State proms(empty sockets) which have to do with sound. I know the sound work as I used proms off a working board to test it.

Rambling. You can use a Sync bus controller off pacman on these boards. Good thing about these is there no wire that has to be connected to the board. The wire that is connected to the board from the regular Syncbus controller connects to a 74ls00 @ A2 pin 2 I find its a good idea to shorten the pins on the syncbus controller to make it sit just above the roms. Makes everything nice,compact and neat.

Gallag - Galaga Bootleg

CPU Board

Name CKSM Type Loc Label Notes

2732-G1.4B DC00 2732 4B G1 2732-G2.4C 5900 2732 4C G2 Gallag name 2732-G3.4CG 5B00 2732 4C G2G Galaga name 2732-G3.4D 0E00 2732 4D G3 2732-G4.4E 5200 2732 4E G4 2732-G5.4J B2FF 2732 4J G5 Standard Fire 2732-G5.4JF B7FF 2732 4J G5F Rapid Fire chip 2732-G6.5E D121 2732 5E G6 Starfield ROM 2732-G7.4K 66FF 2732 4K G7 82S129-2.5M 0715 82S129 5M 2 Sound 82S129-3.1L 074C 82S129 1L 3

Video Board

Name CKSM Type Loc Label Notes

2732-G9.5R D60A 2732 5R G9 2732-G10.7A B18E 2732 7A G10 2732-G11.6A 6627 2732 6A G11 82S123-1.9P 0E48 82S123 9P 1 82S129-4.4P 0241 82S129 4P 4 82S129-5.1D 01C0 82S129 1D 5

There is a small daugher card in a 28 pin socket at 4F.

Gallag 2114 RAM error codes:

Video Board 6F RAM 2L 6H RAM 2H 6J RAM 4L 6K RAM 4H 6L RAM 3L 6M RAM 3H

CPU Board 5D the game displays "RAM OK" but you can't exit the setup page 5C the game displays "RAM OK", then reboot forever

Info taken from various sources from the net can't remember about the rom info, but the ram errors and pinouts were taken from Mikes Arcade

Back to PCB Repair Index