EEVblog #1301 - Arcade Machine Repair

Tragedy in the EEVblog lab as the arcade machine releases the magic smoke.
Claytons repair time.

#Repair #Arcade

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[MrZenerTech]

Somewhere around halfway through the video I had guessed the problem to be a bad solder joint. There were two clues to suggest I was probably correct.
The first was the horribly faulty solder joints found to early on. My experience has shown that when I find joints like that on a board, it's very probable that other joints will be faulty/suspect as well.
The second clue was the very fragile and intermittent nature of the faults. Some joint(s) "teetering" on the edge of conductivity.


Later in the video, I had a second guess that a transistor may be at fault. Thinking maybe spurious oscillations or ripple activity across a faulty p-n junction happening within the conductivity threshold region. I figured either scenario may make the transistor sporadically conduct.

[Mrwheresmyhouse]

"Dry as a dead dingo's donger" has to be the most Australian thing I've ever heard.

[tcpnetworks]

When you say "full wave bridge rectifier", I hear Mehdi Sadaghdar in my head. You know - at 135dB/80Hz.

[martijnholland]

Who soldered that ? Stevie Wonder. My tea came out of nose while bursting out laughing :-)

[mscir]

Dry as a dead dingo's donger.
Who soldered that, Stevie Wonder?
You can see it's just going silly-buggers.
I wish I'd had this guy for my ET classes, so entertaining.
LMFAO

[dirk]

As an old IBEW member, I am still learning electronics. Go figure, I thought motor control circuits was difficult during my apprenticeship but learning the ins and outs of electronics brings that to a whole new level. I just bought my first oscilloscope(a cheap Sigilent) just to learn more. Special thanks to all the commenters that help also. I am amazed by so many people and their knowledge of electronics. Keep up the videos.

[efa]

I'll never get sick of the Muriel's Wedding quote.

[AlexZander]

I would so like to see Dave take on an authentic dedicated arcade game repair. Atari Tempest, Williams Defender, etc

Linear power supplies, vector monitors, raster monitors, gigantic game pcbs, oh yeah!
Arcade games just look better on a CRT.

[emolatur]

those power supplies are actually quite common in the arcade industry.

I work at an arcade in Maine (northeast USA), I've seen (and repurposed) a lot of those.

[cuteswan]

So after 35 years of _CONTINRED_ use the power supply evolved into a Chaos Engine? Cool. Thanks for the goodtroubleshooting & explanations.

[tmd]

Dave, There is a reason for those notches. It is an old school method of allowing wave soldering a board with missing melt-able components like connectors. The wave does not flow over the break and keeps the hole open so the connector can be manually soldered later.

[rodrigocastro]

these are the type of videos I enjoy the most

[JWalterHawkes]

I’ll never get sick of Dave troubleshooting power supplies.

[Melamamoduro]

"For Continred protection against fire" in the board.

[tonysfun]

Nice troubleshooting! I learned something again, nice a clean commentary that I enjoy! You stay healthy and keep up the videos coming!

[williamsquires]

Time to stick a bone-stock gaming PC in there. Considering all the “random” PCs you’ve fished out of the dumpster, there ought to be one lying around somewhere! 😆

[GeoffSteeleAU]

This is just as valuable as the ones where you solve it directly Dave. If only to make me (as a mere mortal) feel far better for my own troubleshooting nightmares

[Zodliness]

@EEVblog I nearly always find dry joints responsible for many of the intermittent faults I receive. They're often a pain to diagnose especially in power supplies around transistor connections, where cheaper components have tarnished legs from initial assemsbly. Removing the unit from its case, relieves tension on the board and sometimes makes it even harder to locate a fault. Like you, I find it's less grief to simply retouch all joints with leaded solder (pre-fluxed) and repeat the soak test. Thanks for sharing. 👍

[FnordOok]

I suspect the reason that PSU was in there originally is that some older JAMMA boards need -5VDC and I think I saw that on the supply side.

[TopRPDRvideos]

Dave you forgot the golden rule... always reflow EVERYTHING before you even start troubleshooting!