New Life Games LLC
NLG Users Repair Logs and Other Ramblings. Request your very own topic. Just ask any site staff. => Channelmaniac's Arcadecomponents' Old School Repair Logs => Topic started by: channelmaniac on May 04, 2014, 07:57:37 PM
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Model: Mr. Do's Castle
Symptom: Upgrade to NVRAM
Removed and reprogrammed ROMs 1 through 4 with the JROK code for adding the High Save Score feature. Removed 1 SRAM and replaced it with a socket and a customer supplied DS1220 NVRAM chip.
Board would not boot with the DS1220 in the socket. Installed a 9 pin 470 ohm resistor pack to tie the first 8 address lines high and tested successfully with the DS1220 in the socket.
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Model: Mr. Do
Symptom: No sync
Board had been modified to put separate H and V sync out. Removed 2 jumper wires and resoldered two cut chip pins to remove mod. Tested. board.
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Model: Cosmic Avenger
Symptom: Will not coin up
Boardset requires +5v on the coin inputs when idle and is detailed in the owner's manual wiring diagram. Either wire +5v straight to the switches or simply use a 1K ohm resistor on each coin switch input on the PC board to tie the inputs to +5v.
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Model: Snapjack
Symptom: Dead
Board had physical damage - scraped traces and a missing crystal.
Replaced the 9.828MHz crystal and tested. Game was dead. Replaced 1 bad Program ROM and game booted, but the game played upside down and player graphics were garbled. Patched 4 gouged traces to fix upside down image and most of the player graphic issues. The player sprites were split and placed on wrong sections of the screen. Replaced a bad 2114 RAM to fix the player sprites and tested.
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Model: Space Panic
Symptom: Dead, missing parts
Board was parted out for the EPROMs.
Replaced 12 missing EPROMs and 9 electrolytic capacitors. Tested. Replaced missing board mounting hardware and standoffs. Retested.
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Model: Ladybug
Symptom: Dead.
Replaced 2 caps to fix the Power-on-Reset circuit. Board booted but had no sound and corrupt graphics. Replaced defective 74LS393 at R5 to fix the graphics corruption. Replaced LM324 op-amp, 10 capacitors, and the HA1388 amplifier IC to fix the audio amp circuit. Tested.
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Model: Ladybug
Symptom: Maze (background) graphics corrupt
Checked the 2114 RAMs and found one with a dead data output. When shorted to the data pin next to it the display cleared up dramatically. Replaced bad RAM and tested.
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Model: Ladybug
Symptom: Dead. Nothing on screen.
Replaced a bad 74LS161 in the clock dividing circuit. One output pin plus the carry pin were stuck low. Replaced 2x 470uf and 4x 220uf capacitors on the CPU board to fix missing sound. Replaced a physically damaged 220uf cap on the video board. Tested.
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Model: Mr. Do
Symptom: Sparkling graphics
Replaced a bad graphics ROM and tested.