Donkey Kong (TKG4) Arcade PCB Repair 03-28-2022

[@ovalteen4404]

The typical reasons to glue down a coil are strain relief and vibration resistance. You'll also find that glue in switching power supplies and the like.

[@captainkevski566]

Good repair. Well spotted on the missing coil. You have a lot of cool kit. Thoroughly enjoyed the Vid Mike. Greets from England from an Arcade Nut who grew up with these machines taking all my pocket money. 👌👍

[@gamernes4195]

Great repair Mike. Keep the videos coming.

[@sydtopia1]

Nice video. I was wondering if the chips your mentioned that do timing, if one of them was out would cause the video, sound or CPU to run slower or faster than normal? Or does the whole board follow the same timing?

[@MikesArcadecom]

Great question. The entire board runs off the same main clock.

[@sydtopia1]

@@MikesArcadecom Thanks, I thought that was the case, it would be too hard otherwise I think to keep everything running together.

[@bondscalper]

I would like to see a video of the board being washed. Really I would. Great video !!!

[@MikesArcadecom]

I'll do a smoke damaged board and see how a video comes out. Thanks for the suggestion.

[@МаксимВолодимирович-с2х]

Good job Mike! Question: why didn't you turn the monitor to a vertical position? By the way, the sound of this machine is very atmospheric! 😍

[@MikesArcadecom]

Thanks! I generally just leave the monitor in it's natural position. I love the Donkey Kong sounds too.

[@CosmicCleric]

@@MikesArcadecom Just curious, is it a personal preference, or a fear of it falling off the shelf if its vertical (since its made to stand horizontally), or ??

[@MikesArcadecom]

@@CosmicCleric well, i fix Midway boards too, (Pac & Galaga), which are turned the opposite direction. And Punch-Out's, which are horizontal. The monitor sits back about 3 feet from the front of the bench, and up about the same on the shelf. It's a bit awkward to flip it on its side over the bench. So, i just leave it in it's natural position. A happy medium.

[@CosmicCleric]

@@MikesArcadecom Thanks for the clarification. Loved the video.

[@aleksandrbmelnikov]

You also have a high pitched sound when you power it on. At least your audio is being recorded well.

[@Edmden0582]

Mike, the more videos you make, the more i'll watch!! :D That ECL (10136?) on E1 of the Video board looked like it was missing a heat sink... A friend of mine had their PCB run for a while but would have sprite issues after maybe 15 minutes. We found re-attaching a heat sink seemed to resolve that issue. Have you seen missing heat sinks become a problem once a board is running for a while?

[@MikesArcadecom]

I haven't seen that, but i bet with overvoltage, it could be an issue.

[@aleksandrbmelnikov]

Nice n Anti-Static bag might be a little nicer. Pack it between bags of (unbuttered!) popcorn.🍿

[@MattyMosArcade]

I need that magnifying lamp. I love lamp.

[@MikesArcadecom]

I got it on Amazon. Makes repairs much easier for me.. YOUKOYI LED Magnifying Lamp Metal... www.amazon.com/dp/B07F8R4GZ6?ref=ppx_pop_mob_ap_share

[@waynegram8907]

Any reasons why they used ECL RAM for the character and spirit video? I know that ECL RAM is faster but you have to use a different clock frequency and also level shift the logic signals to ECL.

[@MikesArcadecom]

Great question! I believe it was to make things more expensive to bootleg and/or reverse engineer. Or an engineer at Ikegami just loved ecl. They used ECL starting with Radar Scope and used the same basic board design until Popeye & Mario Bros.

[@aleksandrbmelnikov]

I remember a 486 owner who asked why couldn't i just download a Pentium into his computer. Simple, because you need to pour the magic Pentium seeds all over and water them each day.🤣

[@WinrichNaujoks]

That was super interesting! What does the coil actually do?

[@MikesArcadecom]

The coil drops the frequency of the clock to feed the ecl circuitry. The ecls then chop up the freq further and spit out 3 8MHz ttl level clocks to feed everything else at the 10125 at 1H on the video pcb.

[@FelinoAnticomunista]

New subscriber here

[@MikesArcadecom]

Welcome Marco!

[@DerekDavis213]

Donkey Kong is available arcade-perfect in many PC emulators, so repairing arcade machines that are 40 years old seems less necessary these days?

[@MikesArcadecom]

Emulators are close enough for the casual player. However, the sounds are off on all the emulators, and the inputs are not quite right. Finally, if you don't have original controls, it's just not the same.

[@DerekDavis213]

@@MikesArcadecom Yes there are many coin-op video games that are not very good in emulation, because of the controls: Spy Hunter Paperboy Omega Race Tempest Robotron Defender or Stargate Crazy Climber etc But Donkey Kong (and Junior) play very well on a standard PC keyboard.

[@piratestation69]

I will never understand how to desolder chips... caps are easy chips not to easy... its an art form.