Museum of the Game® & International Arcade Museum® Forums
A Couple of Color Problem Repair Logs: Boomer Rang'r and Bomb Jack
Boomer Rang'r (Data East)
---------------------
Problem: no sync
Diagnosis: common on-line pinout is wrong; sync is on D, green on E, vid gnd common with other GND pins.
Solution: re-wired test rig
Problem: no green signal
Diagnosis: during careful inspection, a broken (gouged) trace was found on the back of the PCB.
Solution: soldered fine-gauge wire across break.
Result: PCB now works fine.
Bomb Jack (Tehkan)
-------------------
Problem: Video reddish tinted all over.
Diagnosis: scoping video output; red video signal is always high (except during vblanks).
Further investigation: following schems backwards from R output, it comes almost directly from a color palette RAM (as opposed to a color PROM, which is more common). The signals on the data lines of this RAM looked different than those for the Green or Blue outputs. Piggybacking a new RAM clears up the problem. [Interestingly, the power-on self-test does check RAM, but apparently not this RAM, as it did not report any problems at bootup.]
Solution: Replaced 2114 RAM @ 6A
Result: PCB now works fine.
PS--also added an NVRAM and installed the JROK high-score save EPROM. Works well, just need to play it a few more times to knock the rest of JROK's initials off of there...
PPS-- YOU ARE LUCY!
Boomer Rang'r (Data East)
---------------------
Problem: no sync
Diagnosis: common on-line pinout is wrong; sync is on D, green on E, vid gnd common with other GND pins.
Solution: re-wired test rig
Problem: no green signal
Diagnosis: during careful inspection, a broken (gouged) trace was found on the back of the PCB.
Solution: soldered fine-gauge wire across break.
Result: PCB now works fine.
Bomb Jack (Tehkan)
-------------------
Problem: Video reddish tinted all over.
Diagnosis: scoping video output; red video signal is always high (except during vblanks).
Further investigation: following schems backwards from R output, it comes almost directly from a color palette RAM (as opposed to a color PROM, which is more common). The signals on the data lines of this RAM looked different than those for the Green or Blue outputs. Piggybacking a new RAM clears up the problem. [Interestingly, the power-on self-test does check RAM, but apparently not this RAM, as it did not report any problems at bootup.]
Solution: Replaced 2114 RAM @ 6A
Result: PCB now works fine.
PS--also added an NVRAM and installed the JROK high-score save EPROM. Works well, just need to play it a few more times to knock the rest of JROK's initials off of there...
PPS-- YOU ARE LUCY!