Moon Patrol Repair - The Hard Way
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- Опубликовано: 3 авг 2024
- Definitely make this harder than it needed to be but learn a few lessons along the way.
00:00 Intro and Symptom
02:00 Test Mode at Cabinet
06:52 Replace SRAM for the worse
07:30 Bench Testing - No sync?
14:30 Fluke Bad Power Supply
18:00 Down Wrong Path - Buffer Enable
27:04 Misdiagnose with Comparator
31:00 RTFM on right path Data Lines Low
34:00 Fix Sync issues
37:13 NG RAM E000 / Fluke Ram Short
44:25 CPU Board Fixed
46:10 Bad Background Graphics / Board C BPROM @ 1M
50:00 Quick play. 
Игры
Nice job you stuck with it and never gave up. I agree that the problem was limited to the 74LS245 octal tri-state, 8-bit bus transceiver buffer.
Most of those chips on the arcade game boards are buffers which control and multiplex the data and address bus.
I have been chewing over an in-circuit IC identifiers and diagnostics project that would streamline the repair of these boards for a long time. Thanx for a great video. Innocent entertainment. 5☆
Thanks for the nice comment. I had to go back and watch as I forget as much as I learn in these darn things. I haven't used any of them, yet, but check out some links to in-cirucit testers in this thread.... forums.arcade-museum.com/threads/backbit-chip-tester-inquisitor-ic-testing-system-opinions.486739/
You already have all the tech tool gear and experience. Far as I can see all that you needs do now is streamline your game brother.
Cash, cheque or card sir? ...
30-mins labor to repair plus IC parts... that will be $88 plus tax please sir.
@@jacklick
Streamline and get a dozen boards a day restored to working condition, get paid, go home to your wife who is a beautiful cook, sit down to enjoy a meal with fine wine, smoke a cigar, listen to the radio for an hour, grab your wife by the hand and lead her to your onsuite bedroom and make passionate love for eight minutes followed by cuddling her for three hours, fall asleep, wake up and repeat loop back to step one and repair more boards.
Is this the plot of life?
I have a day job but that sounds like a pretty decent life. Just doing repairs because it is interesting, challenging, rewarding, etc.
Self induced problems are the worst.. Good video.. I wanna join the Fluke club too at some point..
Yea, I definitely created more work and more learning opportunities for myself on this one. Thanks for watching and good luck on your search for a fluke.
Many arcade games use Flip flops IC chips. When the Flip flop IC chip is working correctly the Preset Pin is LOW and the Clear pin is LOW, which the Q output will be toggling and following the Data input while being clocked. When the Flip Flop IC chip is being FORCED in an "undetermined state" when both Preset Pin and Clear pins are tied HIGH the Q output is toggling from high to low. When a flip flop IC chip is forced in undetermined states the Q output is toggling data just like a good working flip flop. Have you seen this happening in arcade games when the Flip flop chips are being forced in undetermined states based on the truth tables and the Q output is toggling from high to low looking like its data on an oscilloscope or logic probe is pulsing data? This will fool most electronic techs because it looks like its a working flip flop because the Q output is toggling by being forced in an undetermined state based on the truth table.
I am sure it would fool me. I don't have enough experience or good enough memory to know if I have seen this behavior.
@@jacklick When the signals upstream being applied to the Flip flops preset and clear inputs forcing it in undetermined state based on the truth table of the flip flop chip. The Q output will be toggling so the logic probe and oscilloscope will look like it has good data signals. Not sure if you have see when flip flops have been forced into undetermined states or what would cause flip flop chips to be forced into undetermined states to that the Q output is toggling?
On the Fluke 9010A is there a button to test the power supply? because you fluke was displaying if the power supply is Good or Bad but not sure which button your pressed to test the power supply. Why was the Bad PROM chip not displaying the mountains, any reasons why it deleted the mountains but the car and other graphics were working? When you put the arcade game into test mode you flipped the dipswitch setting, but does the dipswitch setting do to the CPU and ROM chips to put the game into test mode?
It is not really testing the power supply but rather sensing the power at the POD from UUT z80 socket. It does this test automatically. Re. Prom and what is responsible for, I know what you know from the video. This prom just isn't part of the ckt for those other graphics. DIP switch set a Data Line either high or low and I assume the software code looks for that on boot and if it sees it set, jumps to another part of code that runs diagnostic. I am not a programmer though.
@@jacklick When the fluke 9010A has a BTS error the address its display is telling you which ROM or RAM chip is bad. So you can look at the memory map and see which address ram is for which RAM chip or ROM chip or you can use your logic probe and see which RAM or ROM chip "chip select pin" is Enabled. This is the only way you can know which address is going to which RAM or ROM chip when the fluke is display a BTS error listing the address?
Yea that is the general idea.
@@jacklick the other way is to take the bad BTS address that is an address Hexidecimal value and convert it to a binary value that will be the binary value to the address decoder Input pins. The CPU will write a binary data value into the address decoders input pins. I haven't seen any of your videos repair doing it the long way as taking the address value that is displayed on the fluke 9010A and converting that address value to a binary value to apply it to the address decoder circuit and trying to figure out which ROM or RAM chip should be turn ON and turned ON when getting a BTS error or DCD Error. Try doing this in your future repair videos because you will learn how the address decoder circuits work by doing it the long way instead of using the memory map cheat sheet.