Boards Cabinets Manuals/Flyers Cabinet Picture Archive Operator Trips UKVAC Meets Misc. Cabinets & Parts Boards My eBay Sales Components Misc. Repair Log Board Hacks Custom Chips 74 Series IC Info Atari ARII PSU Misc. Add To Favorites UKVAC Wiretap eBay UK - Arcade More Links....	A-H / I-P / Q-Z / 0-9 Knights of the Round Knuckle Joe Lethal Enforcers Mappy Moon Cresta Moonwalker Nemesis Neo-Geo (1-Slot) Nunchackun Pac Man Pacland Paperboy Pengo Pocket Gal (Bootleg) Knights of the Round Fault Solution Performs ram test and then displays some hex numbers and hangs. Although all of the RAM tests said OK, the CPU work RAM was found to be at fault. Replacing the ram fixed the fault. Knuckle Joe Fault Solution Every other line of the sprites are transparent. One of the AM2148 sprite buffer RAM chips was found to be faulty and was replaced. This fixed the problem. Lethal Enforcers Fault Solution No sound. Several of the pins on the audio amplifier had been bent (They are quite long) and were shorting. Re-positioning the pins fixed the fault. Mappy Fault Solution Every other row of the sprites is blank/missing. Some of the address lines to the sprite ram (MBM2148L-55 at location 3E) were constantly low. The address lines were generated by a 74LS161A counter at location 3J. Replacing the 74LS161A fixed the fault. Moon Cresta Fault Solution The alien sprites are corrupt (stable but the wrong graphics) There is a 3-way cable that connects to the character ROM daughter board. The cable is driven by a 74LS259 (8-Bit addressable latch) at location 9M. The outputs Q0-Q2 were stuck high even though the bits were being written to. Replacing the 74LS259 fixed the fault. No ship fire sound. The input of the analogue switch at 7R (4066) was permanently high even though the signal that drives it was low (the signals are seperated by a diode). Replacing the 4066 fixed this and the shot sound signal now reaches the amp (LM324) at 7T but the amp has no output. Replacing the LM324 fixed the fault. No ship explode sound. Bad amp (LM324) at 7T. Replacing the amp fixed the fault. The game runs very slow. Bad 7402 at location 3R. Some outputs were open-circuit. The sprite colours are wrong. Each sprite is a single colour and has parts missing. (MC-1FJ Board) Testing the output of the 5 2147 sprite rams showed that there was data present on all 5 ICs but testing the same signal on the board showed a missing signal. The output pin on one of the IC sockets was squashed so the signal didn't reach the board. Repairing the socket fixed the fault. Moonwalker Fault Solution Dead. Moonwalker is a Sega system18 board that uses a custom CPU with battery backed security. I had a CPU from another moonwalker board that I tried. It didn't work straight away but I noticed that the part numbers were different. The roms ROM-E and ROM-O on the rom board need to match the CPU so after changing them the board started to work. Nemesis Fault Solution Startup test indicates 'OBJ RAM - BAD' Replaced the ram at D25 (2128-15). Neo-Geo (1-Slot) Fault Solution Boots up with a cross hatch and hangs. There was a tiny scratch on the bottom of the board which had broken 2 tracks to the connector. Repairing these tracks fixed the problem. The colours were slightly wrong. (Mk.2 Board) Video data is latched into 74LS273. The output of the latch drives a R2R resistor network to generate the analogue video output. Some of the outputs of the latch were shorted to GND. Replacing the 74LS273 fixed the fault. Nunchackun Fault Solution Graphics Bad, really bad. It is just possible to see some of the game graphics through an 'interference' type noise. The colour data is latched into a 74LS273 which then drives 3 24S10 bipolar proms whose output is fed though a discrete resistor DAC to produce the analogue video signals. The output of the 74LS273 was sat at about 1.5V with about 100mV of noise which contained some of the video data. Replacing the 74LS273 fixed the fault. All sprites are made up of horizontal coloured bars. The low sprite ROM address lines get latched through two 74LS273s (in series) before passing through the flip circuit to the EPROM. The outputs of the first 74LS273 ( at location C14 on the bottom board) were stuck at about 0.5V while the clock and inputs were active. Replacing this 74LS273 fixed the fault. Pac Man Fault Solution No Sound (2 board version) The outputs of the sound data latch (74LS273 at location 2M on the bottom board) were all stuck low except for one which was sat at about 3V. Replacing this IC fixed the fault. Pacland Fault Solution Game resets when credited with COIN1 or COIN2 inputs but is ok when credited with SERVICE input. The custom IC (Red/Brown hybrid circuit) at location 1F has previously been snapped off and resoldered. Resoldering the pins (actually they are solder bridges holding the IC on) fixed the fault. Paperboy Fault Solution Dead. Garbage on screen. One of the EPROMs was the wrong version (it was a Paperboy EPROM and in the correct location and did even checkout ok). Replacing this eprom with the correct version fixed the board. Pengo Fault Solution No Display. Game coins-up and plays. IC78, Labelled PR-1633 (This IC is a 82S030 Bipolar Prom) was dead. Replacing this led to the next fault below. Display is bright purple. Game coins-up and plays. The output of IC101 (74LS375) that drives IC95 was stuck at 1.5v. Replacing IC101 fixed the problem. Pocket Gal (Bootleg) Fault Solution Some of the background graphics blocks were corrupt and flickering. A12 of one of the background graphics ROMs was floating at about 1V. A12 was driven by the output of a D-Type flip flop (74LS273). Replacing the 74LS273 fixed the fault.