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Pretty much same for me, except immediately I suspected a faulty solder joint, about halfway I thought maybe it was the 16 pin or so IC...

Thanks Dave ! Even you can't find the exact fault but it is still an outstanding PSU diagnostic ever with scope and explaination thrown in it. Great video ! PC supply is a way to go since a cooler is an added bonus.

Re-soldering suspect joints has never worked for me especially in my early days unless I can see a physical crack and sparking around the joint :-)

Yet again, it's not a work of art so Dave condemns it as bad. Appearance is not everything, Dave. What a surprise. The joints on the main connector do not necessarily look dry at all, it just looks like too much solder has been used, and that does not affect the function. Some flux smells nasty and leaves residue; that's life. The IC is not obviously badly soldered, it's just that the flux has not been cleaned off so it does not look pretty, but those solder joints, upon first inspection, do not look suspect. You are getting a little too arrogant these days, Dave. Maybe have a refreshing look at your really old videos where you had a little more humility. You're very good at your thing; you don't need to show off. I don't disagree with your final microcrack / dry joint theory, but it's simply not often obvious. Electrolytic cap ageing is also a suspect. SMPS are often a complete pig to diagnose and fix. Most mass produced stuff is only just on the right edge of working; the components are getting hammered and it's all just nasty.

@@andrewhannay I try to narrow down the options first. That's an absolute last resort for me as touching around without intention has always lead me to more problems than solutions...

Bloody oath mate. Aussie, Aussie, Aussie. Oi, Oi, Oi!

😂😂 One shock and im gone!

& after the wildfire

"FOOL BREEJ REK-TI-FA-YA!"

@@Okurka. yeah, it's "FULL BRIDGE RECTIFIER!"

LMAO!

Everything is hanky-dory. :)

@@volodymyrzakolodyazhny7740 - Purely FYI - Here in NZ it's pronounced with an 'O' as in hOnky dory. I think Aussie is the same (they ALWAYS seem to copy what we do here)

@@trevorvanbremen4718 ..... Lamingtons,

i gotta be honest, i felt that he did a disservice to stevie wonder on that joke. I would have picked on a crack head

I'm literally lying here trying not to wake anyone else in the house I'm laughing so hard.

I lost it at that

agreed

The joints didnt look that bad and clearly not dry, it was just too much solder and the flux was not removed. A dry joint looks different.

I just about died at that! Great stuff. How come we didn't have dave as a teacher in collage?

Here I thought he was quoting Courage the Cowardly Dog 😁

31:45 in case anyone missed it (lots of other times too)

LoL, never seen that until someone pointed out

this type of typo on chinese products hasn't changed since '84.

Also giant soda can sized caps in some of them.

@@Membrane556 That never fail.

@@Membrane556 Atari's "Big Blue".

Yeah and they're cheap as chips.

Hi mate, some advice if i could first a few questions You say you WORKED in an arcade. does that mean you operated the arcade only or you repaired machines as well I'm interested to speak to you if you have in depth repair experience and i'm happy to pay you for your time to speak i'm not new to electronics , i would just like to get the opinion of one who has repaired machines before I have an old Black and white knock off Space invaders cocktail table, Dual player obviously goes without saying... Black and White CRT on board it still works, no problem it was gifted to me vs the client throwing it in the bin. I've had a look around it, it seems like the caps could do with a replacing, all else seems ok I HAVE 2 ISSUES Initially the issue was ISSUE 1 - Upon Start up it would start normally, Expect the V Hold and H hold would be screwy. Now.. i have found 2 Pots inside that if i turn then, Obviously V and H Hold Pots, i can adjust it and it's fine QUESTION 1 - WHY, AFTER SHUTDOWN DOES THE V and H hold gets screwy again ? Now another problem developed it happened once, i disconnected the (let's call it CONNECTION BLOCK) from the game board and re connected it and it fixed the problem Now the problem has returned and won't go away ISSUE 2 - Unlike before, when the game now starts i don't see normal characters, i see Letters D's and T's Mostly i think. as if... the game didn't load up correctly simply put WHAT THE FUCK IS GOING ON LOL so as you can see.. I need some input from someone who has experience with these things. I could probably take a whole heap of time and go through it and find the issue, but it'd be cool to speak to someone with some experience as well so.. is that you, or did you just run the arcade or did you actually fix the machines

​@@martinkuliza while it is seasonal, I *believe* I /still/ work at an arcade. I mean if I show up for work in April and they tell me to go home I'll know otherwise, but unless that happens, let's be gentle with Mr. Ed. He's old and doesn't need a full ado about nothing! Barring unforseen changes, I am a tech and also an assistant manager. Now. As to your other issues. The horizontal and vertical issues are almost certainly dried out capacitors in their respective oscillator circuits. They are obviously designed to lock to the sync pulses in the input signal but in order to do that they have to be close to the correct frequency to begin with. Lots of tuned bits there: coils and caps. Any component that changes in value changes the frequency. A common failure mode of electrolytic capacitors, before they fail completely, is to become thermal: when they're cold, they're either low value or very high esr, but as they warm up, they start behaving more like capacitors again. I'm gonna guess you've got a few caps that are drying out, and you're setting the h/v hold to compensate for whatever value they are while it's running, and then it's out of spec when they cool off. The sync stuff is generic to all 100% analog raster displays, and hopefully helps. The logic issue, on the other hand, will be specific to that game board, but if manipulating the "CONNECTION BLOCK" (close enough. "connector," although there's probably a dozen and you haven't really specified which one) treated the problem before, I'd start with some electrical contact cleaner (deoxit) and a close inspection on and around said connector for bad solder joints.

@@emolatur " let's be gentle with Mr. Ed. He's old and doesn't need a full ado about nothing!" Understood... Do Lets "Barring unforseen changes, I am a tech and also an assistant manager." Thank you and now that Pleasantries are aside we can get to business "Now. As to your other issues." Precisely "The horizontal and vertical issues are almost certainly dried out capacitors in their respective oscillator circuits" I suspected as much, and i don't really need too much help on this front, the confirmation was enough As for the rest I was going to go around and inspect the solder joints ALL OF THEM with a microscope , very slowly. My other guesses would be, there are 2 boards, the bottom board seems to have the EEPROM's the top board seem to have i think (of memory) 8 was D.I.P. switch. and a few pots that seem to control the speed of the good ship and the aliens and the bullet speed and ship speed and alien speed and sound level. i have 2 guesses why the screen Characters are filling up with D and T all over the place. either something with the D.I.P. but.. i haven't touched it or more likely, badly seated EEPROM's, in my mind it has to have something to do with the Character ROM doesn't it ? that's what i've got so far. I suspect maybe the ROM's may need reflashing, but GUT FEELING says, Likely that won't be necessary. previously, it was working fine, other than the V and H hold and i'd adjust a board that was mounted vertically a little under the Power supply and to the right of the monitor, there was a Pot there and that'd fix the Hold, other than that. the game actually worked perfectly Player 2 button doesn't fire, but.. that's just a button replacement, Nothing to worry about, it wasn't until recently that the game upon start up produces DT T DDDDTTTDDDTT D's and T's in some spots you can see half a space invader here and there

@@emolatur Now.. I appreciate the advice. it's one thing to do this on you tubel like this would you be open to me paying you and us doing a zoom session or something If your'e not interested, i understand if you are , I appreciate it. let me know your thoughts . Any help is greatly appreciated. Hope you can help a big kid get his space invaders going and thus retrubition for all those lost credits and coins LOL over the years speak soon I'm a mad max fan, so I REMEMBER A TIME OF CHAOS, AND I REMEMBER THE ROAD WARRIOR , THE MAN WE CALLED "MAX" I also remember a time WHEN WE THOUGHT AS KIDS THAT IF YOU SWITCHED OFF THE SPACE INVADERS MACHINE QUICKLY AND THEN ON REALLY QUICK YOU'D GET 50 CREDITS LOL, We tried so many times The rumous was As you dropped in 20cents, Just as the 20 cent piece gives you the credit, you'd switch it off and on really fast while the owner of the arcade wasn't looking and you'd get 50 credits NEVER BLOODY WORKED :P

Glad I'm not the only one who noticed that, lol

Oh i see it...you mean the small one on the thick trace with crack between the solder and the leg of some component...right?

He knew what board he was putting into the new custom made cabinet though.

@@EEVblog Agree, but if he also deals with standard arcade stuff, he probably just stocked those in bulk.. Those power supply types are very common in that vintage arcade machine.. My Frogger machine has one, and it needs the -5v for the audio amp..

@@EEVblog Pretty sure ATX supply -5v too, though that PSU predates the ATX standard by a decade.

@@EEVblog all iover eBay - common ... also Suzzo Happy branded ones are supposed to give us confidence

@@RenThraysk I think modern ATX supplies have dropped that voltage rail (or maybe it was the -12V) either way i believe your modern ATX supplies have much less current capacity on the negative rails than they did back in the day.

not if you just play a few classic arcade games, this thing instantly powers up. En you don't have to worry about shutting it down.

Excluding the POST (which is not a problem on an ARM board), a Linux session can usually boot in less than 10 seconds so it's not a big deal. Also, it's always possible to use a live usb in read-only or a small UPS (often built-in an SBC or a laptop board) if the power shortage is a concern.

I tend to agree. MAME with Hyperspin as a front end looks killer, is easy to navigate and with it being on a PC, you have the option of adding more games than what comes on that little iCade 60 in 1 board.

Never heard it actually

Or AvE's Rectum Fryer... :D

Or as I would say when I run across bad a bad full Bridge rectifier. A full Bridge rectifier that's been wrecked a fried!!!!! You know that we'll still there was two diodes fell short circuit. Is socially instead of being a diode they became a jumper link. Also one time was charging a rechargeable battery a seal when acid those wall adapter/plug packs/ wall wart. And was not careful with by alligator clips that I put on the original poured they had come on clipped and had short it and I smelled something when I went down to my shop and the case of the charger had deformed because the diodes are being overloaded due to the short it was enough to partially deformity case not a switch mode but believe or not the Transformers okay so what up were using it. Ironically the build a nicad charger.!

Also yeah agreed about the electric little thing no.

@@gromett That's what I hear, but with Big Clive's voice.

What's donga?

@@Brainstorm4300 Dong = Penis 😂

@@-dazz- lol

Demonetized!

@@-dazz- i was just going to ask, male or female bit? or is what why he says nun nunna or whatever it is.

I checked that, wasn't it.

so someone else did see it too. i dont know anything about soldering, but that was my guess too..

Nope, trick of light and shadow.

@@EEVblog I thought that too, but it looks like it'd make sense if someone pried out the fuse and knocked the cap next to it.

Must be 2084 then.

Robotron 😎

It's probably not that old, parts look fairly modern and the particular 494 clone in question wasn't out till mid-late 90s. The design is ancient but it used to be pretty modern all the way back then. It also shouldn't require a minimal load, i mean why, the 494 is a fixed oscillator design, so it should always be able to start and keep running just fine.

You answered your own question.

@@EEVblog yes I know I have answered my own question but any way troubleshooting you have done was good enough for most of people who wants to learn power supply deep analysis.

Yup. I kept about 4 or 5 on my truck at any given time. It's still pretty common stuff.

So did I.

Yeah, and cheap to replace. $10 - $20.00. I would never repair one of these. I don't trust their overall construction. If one component went out, others are due to follow. Replace it. It is the equivalent of the heart of your game and if it blows in the wrong way, it can damage the game board.

He should learn hungarian too. Just because we actually have distinct slang words for transistors (tranyó) and transformers (trafó). 😉

@@gabiold "Trafo" is also used in german, never heard a german slang word for transistor though (then again I'm not often around people who use slang in electronics)

@@LordWaldema german slang for transistor is like: transe some other words: widerling for resistor kondi for capacitor poti for potentiometer And the best one of all -> Hühnerfutter for smd resistor/capacitor parts, Hühnerfutter means chicken food like grain. Engeneers often say something like: To solve this problem only two transistors and a hand full resistors / capacitors are needed. Das Problem kann man mit zwei Transen und ner Hand voll Hühnerfutter lösen.

@@farbe123 Kondi and poti are also used in hungarian.

Habe ich auch so verstanden 😁 Genius 👍

Don't see that it would help much, because almost any difference in thermal image between properly working unit and one which fails to bring up the rails is that well some components aren't getting as hot, but why aren't they getting as hot? A very circular cause and effect relationship! If there was a shorting ceramic or tant somewhere then yeah that would flare right up on a thermal camera, but looking at it, there isn't any opportunity for that to happen.