Technos Games

[channelmaniac]

Fixed: Double Dragon 3:
Symptom: Dead/missing parts

IC 79, one of the pair of system ROMs was missing. Burned a replacement EPROM and installed it but board would not boot. Inspected the bottom of the board closely as it looked like it had been badly abused. Fixed 3 shorts (pins from a chip laying over shorting a trace) on the bottom of the board and patched 8 cut traces. Board booted but had no sound. Installed a missing YM3012 Sound DAC (Pulled from a parts board) but still no sound. A closer inspection showed the Z80 CPU had NO activity on its address and data busses. No logic highs, no lows, just dead. Replaced the Z80 and had the same symptoms. Checked the reset line and it was cycling from low to high but doing it incredibly fast. Traced the reset circuit back and found legs in the board but no capacitor in the circuit. Replaced 1 cap in the reset circuit and played the game through to the end.

[channelmaniac]

Fixed: WWF Superstars
Symptom: No video sync

Video Sync line was dead. Traced it back to a resistor that had burned. Traced that back further to a 74LS05 IC that had input and no output. Multimter confirmed the output of the 74LS05 had shorted to ground. Replaced the 74LS05 IC and burnt resistor to fix the sync problem.

[channelmaniac]

Model: Combatribes
Symptom: No video or audio. Only a light blue screen.

The board only gave a light blue screen and had no audio. There were no video artifacts or other garbage on the screen. Coining it up made the screen flash and there was good activity on the main CPU. This was a good sign as this game flashes the screen when a coin is dropped during attract mode.

Tapped on the 2 surface mount chips (IC33 and IC84) and saw video artifacts of the game playing. Reflowed the solder connections on both chips to fix the video.

Inspected the board and found a gouged trace on the bottom of the board leading over to the sound subsystem. Patched the trace and replaced a broken 10uf electrolytic to fix the audio.

Replaced 3 broken 100uf electroltyics on the +5v line to finish the repair.

[channelmaniac]

Model: Combatribes
Symptom: Corrupt graphics and no inputs.

Resoldered the 2 surface mount ICs to fix the background graphics problem. Reseated the PROM at IC43 to fix the missing foreground graphics. Fixed a broken trace going to IC98 to fix the double text problem. Patched a broken trace to fix the input problems and tested.

[channelmaniac]

Model: WWF Wrestlefest
Symptom: Missing background graphics, no blue, and no audio

Resoldered the surface mount ICs but no change on background graphics. Replaced bad SRAM at IC41 to fix the missing audio. Replaced bad SRAM at IC 54 to fix the no blue issue. Replaced bad SRAM at IC27 to fix the missing background graphics and tested game.

[channelmaniac]

Model: Double Dragon
Symptom: Dead

Board would power up and display yellow and white garbage. Checked the ROMs and found garbage on the data lines. Replaced a bad 74LS244 at location IC12 and the CPU would try to boot, but still would not. Found that pin 2 of IC21, a 6264 SRAM IC was stuck high. Traced it back to IC 1, a 74LS157. The LS157 at location IC1 and IC2 were missing their select signal from pin 1. Jumpered pin 1 of IC2 to pin 1 of IC3 to fix the board. Replaced 2 broken caps and tested.

[channelmaniac]

Model: Double Dragon
Symptom: Dead

Board would power up and display yellow and white garbage. Checked the ROMs and found that pin 22, one of the control lines, was dead on IC 25, 24, and 23. Replaced a bad 74LS139 at board location IC72. Board would then power up and run, but would not recognize any inputs. Replaced a bad 74LS138 at location IC90 which allowed it to read the DIP switches, but still no inputs from controls. Checked signals against a known good board and discovered that pin 4 of the CPU, FIRQ*, was not going low when a coin was added. Replaced the 74LS74 at IC73 to fix the board. Replaced 2 broken power decoupling caps and tested the game.

[channelmaniac]

Model: Double Dragon
Symptom: No sound

CPU checked good by substitution. Cleaned the legs on the sound program EPROM. Chip select signals looked good but the SRAM was never going into write mode so the subsystem was never fully booting. Checked continuity on the data and address lines and found a bad connection between the sound ROM and RAM on D3. Patched bad trace and tested the game successfully.

[channelmaniac]

Model: Block Out
Symptom: Dead

Replaced missing A1-2 EPROM and tested.

[channelmaniac]

Model: Double Dragon 3
Symptom: No sync

Replaced a shorted 74LS05 IC and a burned resistor. Tested. Board had no sound. The sound Z80 was dead. Checked the reset line and found it faulty. Replaced a capacitor with a broken leg and tested. Replaced 1 cap in the audio section to finish the repair.

[channelmaniac]

Model: WWF Superstars
Symptom: No audio

Replaced broken volume control. Tested game.

[channelmaniac]

Model: Ninja Gai-Den
Symptom: Dead

Replaced bad 8Kx8 SRAM at U3. Tested.

[channelmaniac]

Model: Ninja Gai-Den
Symptom: Dead

Replaced bad 24MHz crystal oscillator and 2 broken .1uf bypass caps. Tested.

[channelmaniac]

Model: Double Dragon
Symptom: Dead

Repaired 4 damaged traces. Tested.