LIVE! Arcade Re-Repair #3: Midway Mortal Kombat II (Sound problem)

[@mrbrooks9969]

Thx for the extra info on your repair proceedures .

[@DigitalConfusion]

Awesome stuff. Thx for sharing your knowledge. Much appreciated.

[@markherring3513]

That multi meter diode test on the legs...does that only apply to the outputs? Or does the diode test work on the inputs too?

[@kingdbag]

Keep the videos coming... thanks for going into detail on what you are doing with your tools its very helpful.

[@billwilliams6338]

74XX, arcade monitors have a B+ trim pot voltage, why does it control and why does the sync and hold circuit in the arcade monitor need a B+ voltage set at 125vdc for it to work correctly?

[@evilash570]

Great repair!

[@RedHorseAdventures]

This is the same sound board as T2 isn't it?

[@kevinthorn9672]

I got a no led on mine no sound and no bong and does the iq thing also

[@billwilliams6338]

74XX, The FETs or Cells inside the 4116 dram needed +/- 5 and +12 because of what reasons to store the data bit? Because 4164 are Dram also but the cells fets only needed +5vdc to store the data bit, why?

[@jaygallegos8612]

Good shit. I finally got my mk2 pcb but Im not getting the bong tone and no sound. How can you tell if the power chord is bad?

[@spiritvisions13]

Question my mk2 sound board worked red light on but now there is no light on no sound what do you think I should look at other then wiring there in good shape to main pcb thanks

[@74XX_arcade]

As you saw my problem was a logic issue so it can be a number of things on the main board or sound board. I would see if you can get your hands on another sound board to test. Could spend a lot of time testing one or the other not knowing where the problem was!

[@billwilliams6338]

74XX, any reasons why ROM chips don't output IRQ signals and where do IRQ signals come from or what chips generate IRQ signals in arcade games? Each arcade game ROM chips has a ROM signature, how can i use my handheld calculator to compute each ROM signature and ROM checksum? I'm not sure how to calculate the ROM signature and ROM checksum values. Any reasons why arcade games use "shift registers" for what reasons? Nintendo uses ECL RAM chips any reasons why they use ECL RAM chips?

[@74XX_arcade]

IRQ signals do not have anything to do with ROM, they interact with the CPU. You should get an EPROM reader/writer for checksums. Shift registers are one of the fundamental logic types, they are used everywhere for many reasons. Sorry I don't know anything about ECL RAM.

[@WILDGEESE399]

@@74XX_arcade mortal 1 and 2 are they the same board they look so

[@billwilliams6338]

What chips "SEND OUT" IRQ signals to the CPU? can you give examples of when arcade games use shift registers or in other circuits that you know of. The EPROM reader/writer will do the checksum but not the ROM signature any reasons why?

[@M3RIO1]

Hello, great video. Are you by any chance taking boards for repair?

[@74XX_arcade]

Hello, I do take boards for repair but only domestic (in Canada).

[@eloquintmixes]

Hi, I messed up my Mortal Kombat 1 sound board. Can I buy a MK2 soundboard and just replace the Roms? I can't find the MK1 soundboard for sale.

[@74XX_arcade]

No, they are different boards. You can go between MK and NBA Jam with ROM swaps but MK2 is different.

[@Jago-p8p]

I have exactly the same mk2 board , and i also have the sound problem, when i put her on to work in 30-40 seconds the passive cooler on the audio amplifier is very very hot !! Do you have the same thing? I dont know what to do

[@74XX_arcade]

You probably need to replace the audio amp that's attached to the cooler!

[@Jago-p8p]

I connected it to another monitor and its ok . Before i cleaned it very well. It worked perfect. This happened for two reasons first it needed clean or something is wrong with my speaker or the jack. I dont have arcade cabinet i have an old tv shell and inside a chassis and glass (hantarex-videocolour) . One thing is very strange though we both have exactly the same board but why yours the chips have pin baze on them? You change these?

[@uguraltunbilek]

nice video

[@wouldyouohwait]

What province are you in?

[@74XX_arcade]

Hello! I'm in Ontario.

[@JohnSmith-qn3ob]

I have a few MK2 boards and if you want to convert to 8 Mbit roms you have to desolder and move 4 resisters. But then you need to replace the A-17480 chip with A-17748. YourMKArcadeSource did a video on it: kzbin.info/www/bejne/eqimg2ybpsl-bNE