Looking for some help after I tried alot of things. I have a Cactus Jacks that will not boot. I used the pinrepair and pinwiki to do the following:
Removed battery, changed to button battery, cleaned corrosion
Corrosion was on U13 and U10 so cleaned, socketed and replaced the chips
Under U13 there was broken trace from pin 6 ultimately to the LED (see enclosed pic)
After that I would get solid light on MPU and nothing or one solid light on Sound board
Then I replaced the C20 and C21 with 1mf 50v ceramic caps
After that I would get solid light on MPU and nothing or one solid light on Sound board
Then I socketed and replaced U11 with 74HC123E
After that I would get solid light on MPU and nothing or one solid light on Sound board
Then I socketed and replaced U6
After that I would get solid light on MPU and nothing or one solid light on Sound board
The 4mhz crystal still has corrosion, so I plan to order that and replace
Pushing the switch on MPU gets light to blink then return to solid. Switch on sound board does nothing
I have 5v on the MPU, Pin1 on U6 has 5v and pin 2 has the battery voltage
So basically I have a solid MPU LED and no boot.
First question is: the broken trace "Under U13 there was broken trace from pin 6 ultimately to the LED (see enclosed pic)".....is this correct or does this trace not connect in this way? It was the only thing I did outside the repair guides
Next things I will try:
replace R5 and R6 with 680 ohm resistors
replace 4mhz crystal (need to anyway due to corrosion)
Got the test rom from Marco @MarALB (thank you again!), and will have that burned and use it
Anything else I am missing or any other fixes for solid MPU LED after all I changed?
Cactus Jacks repair U13 (resized).jpg