EEVblog #1301 - Arcade Machine Repair - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: April 16, 2020, 11:24:25 pm
content: Tragedy in the EEVblog lab as the arcade machine releases the magic smoke.Claytons repair time.

author: Ketturi
author_rank: Regular Contributor
timestamp: April 16, 2020, 11:51:23 pm
content: As a arcade machine technician I can say that those arcade SMPS's are pretty much considered as a consumables. When a game comes to service, if there is any hint of power related issue or old PSU looks crusty, we will just toss it and put a new one in. Not worth of using any time to do in depth troubleshooting and repair on those as new ones do not cost anything compared to hour rate that would go to fixing one. Some rare systems are exceptions, like those used in Nintendo cabinets that usually do not fail, or just need new capacitors (or are otherwise made from unobtainium).Swapping new power lead and possibly installing isolation 230v to 115v transformer are also common starting points with old cabinets, it just saves time and possibly lives. Feeling that 50Hz buzz when touching coin door is not nice when some yankee btard decided it would be good idea to snip that pesky earth terminal from plug. And power cords are constantly run over with pallet truck or otherwise damaged during transport.Anyway, I find your lack of CRT disturbing

author: EEVblog
author_rank: Unknown
timestamp: April 17, 2020, 12:33:22 am
content: Quote from: Ketturi on April 16, 2020, 11:51:23 pmYep, doesn't surprise me. I wasn't going to reuse the crusty thing anyway.Quote

author: james_s
author_rank: Super Contributor
timestamp: April 17, 2020, 12:38:58 am
content: A lot of people put those disposable switchers into vintage games. I rip them out and restore the original linear power supplies. Yeah they run hot but who cares. Some of them are less than stellar designs but the ones that Atari and Gottlieb used in most of the classics are pretty solid. Once you clean up the ham-fisted repairs of rushed techs back in the day they're pretty reliable. In the case of Gottlieb I also replace the zener reference for the 30V supply to drop that down to 24V, there's no reason for the unobtanium audio amp to be run at the ragged edge.

author: radix
author_rank: Contributor
timestamp: April 17, 2020, 12:53:14 am
content: The 494-based designs (especially designs this old!) usually use BJTs for the main switching transistors. The power supply bootstrap sequence is quite weird and relies on the base drive transformer specifics. It's described on these two sites:http://ludens.cl/Electron/PS40/PS40.html,http://imajeenyus.com/electronics/20151028_smps_variable_voltage/index.shtml. I usually use one of these two schematics as a base when looking at similar PSUs.

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: April 17, 2020, 02:05:45 am
content: My guess at first was a badDio-Deeon the ouput stage that does the DC rectificationI think that power supply looks like something out of piece of eighties medical equipment. Usually in that type of topology you find a opt-coupler between the primary to secondary for feedback reasons on the output voltage(s) Why don't you see that on that board, it has no output feedback ?

author: duckduck
author_rank: Frequent Contributor
timestamp: April 17, 2020, 09:38:46 am
content: This episode reminds me of the book that Atari published back in 1980 (known as "The BOOK") to help new owners of Atari console games repair them when they failed. Kind of an electronics-repair-tech-in-a-book book.https://archive.org/details/atari_thebook/mode/2upAh, the old days...

author: sean0118
author_rank: Frequent Contributor
timestamp: April 17, 2020, 12:52:52 pm
content: The isolation between primary and secondary doesn't seem great.Look at the creepage between the rectified mains and the heatsink / case mounting screw top right at 12:00. They could have added lots more separation than that.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 17, 2020, 01:01:59 pm
content: Quote from: johnlsenchak on April 17, 2020, 02:05:45 amThis was the 80's, when men were still men, women were still women, and a measly zap across the fingers nothing to worry about!

author: Kleinstein
author_rank: Super Contributor
timestamp: April 17, 2020, 08:23:55 pm
content: This supply has the PE connected to the output for a good reason, so it can get away with less creepage distance and the transistors with just the thin isolation mounted to the case.

author: wavebits
author_rank: Contributor
timestamp: April 17, 2020, 08:59:30 pm
content: Dave replaced a crappy throw-away switcher with an even crappier line cord bulge power supply. Spend 20 bucks and get a decent quality supply like a Meanwell and be done with it. Otherwise you will be back in a few years installing another, These sealed laptop type power supplies generally run hot (no ventilation at all) and are usually full of poor quality caps and dicey components. Some are downright dangerous.

author: Wollvieh
author_rank: Contributor
timestamp: April 17, 2020, 10:01:45 pm
content: Is that power supply really a 1984 vintage?I'm not a graduated archeologist like Jean Luc Picard, but during my expeditions in historic circuits I've never seen e.g. these transformers with the yellow tape around in anything before mid-90's. Also that black shiny 1 µF cap does not look much before 2000 to me.Maybe I was cut off from this timeline, by just not getting the real hot stuff as in my experience 80's equipment was copper-iron-brick-style and baking tray-style heat sinks - black anodized, rarely blank - with TO-3 graveyards.I'd appreciate any input, even to prove me wrong, as long as I get explicite pictures with it.

author: Nusa
author_rank: Super Contributor
timestamp: April 17, 2020, 11:59:02 pm
content: Quote from: Wollvieh on April 17, 2020, 10:01:45 pmPresumably 1984 is the major revision date of that PCB, not the date the board was actually made. In which case 1984 is only the earliest date that unit could have been assembled. For all we know the manufacturer used that version of the PCB for ten years, plus or minus. Unless you find newer dates on parts or labels, or a serial number that can be checked, we'll probably never know. So your observations may be correct, without being in conflict with what we see.

author: thm_w
author_rank: Super Contributor
timestamp: April 18, 2020, 12:40:07 am
content: It looks like its a specific "arcade style" supply:https://retroactivearcade.ca/products/arcade-power-supplyMaybe a clone/equivalent of this:https://retroactivearcade.ca/products/suzohapp-arcade-power-supplyQuote from: wavebits on April 17, 2020, 08:59:30 pmThey will run hot if the output load is high.In this case his is 5V/2A, 12V/2A. I can't find much info on the jamma board, but most likely 12V supply is almost nothing and 5V is 1-2A or so?If that is the case it would be running at ~30% of full load.Quote from: Nusa on April 17, 2020, 11:59:02 pmDefinitely, could be even longer than 10 years.I think Rubycon BXA came out 1995-2000 ish? and ended in 2013. My guess is its made a few years before he bought the arcade machine, maybe ~2000.

author: EEVblog
author_rank: Unknown
timestamp: April 18, 2020, 11:23:00 am
content: Quote from: wavebits on April 17, 2020, 08:59:30 pmI wasn't going to wait to order a supply when I had one available that did the job and got it back working immediately. Will likely last a lot longer than you expect. It's not being used anywhere near it's rated capacity, nor is it used in a hot environment.

author: EEVblog
author_rank: Unknown
timestamp: April 18, 2020, 11:25:56 am
content: Quote from: thm_w on April 18, 2020, 12:40:07 amLooks and feels at least 20 years vintage to me. There were no other identifiers.

author: Zero999
author_rank: Super Contributor
timestamp: April 19, 2020, 09:41:05 am
content: Quote from: EEVblog on April 18, 2020, 11:25:56 amDon't forget the power supply had already been repaired before, so it's highly likely many of the parts will not be the originals, especially the capacitors which often go bad.Anyway, thanks for doing the video. Of course it's not worth repairing, only for it to go wrong again, but there are often other reasons for repairing things than usefulness: educational, fun or making YT videos. I did a similar thing at work, when I had a couple of hours to spare, simply to pass the time and demonstrate to the boss I could fix it, if the replacement didn't come in time.

author: Brumby
author_rank: Unknown
timestamp: April 19, 2020, 12:11:20 pm
content: One of the less obvious lessons is demonstrated here...The one where you cut your losses and move on. The commercial term is BER - Beyond Economical Repair. Yes, we hobbyists redefine what "economical" means to us, but even in our own quiet world, there comes a time when you need to "call it".

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 19, 2020, 04:21:45 pm
content: Haha, that schematic, always love it when my schematic symbols show up randomly. That was back in the day when you were as well off with Paint as any other free schematic tool... not like today when the free ones are actually good.The "official standard" for those curious:https://www.seventransistorlabs.com/tmoranwms/Elec_Circuit_Rules.htmlTim

author: BurnedResistor
author_rank: Regular Contributor
timestamp: April 22, 2020, 08:57:56 am
content: "Dryer than a dead dingo's donger, who soldered that - Stevie Wonder?" has to be pretty high up the list of Dave 1-liners.

author: EEVblog
author_rank: Unknown
timestamp: April 22, 2020, 01:54:38 pm
content: Quote from: Zero999 on April 19, 2020, 09:41:05 amAfter the video was shot it did actually seem to hiccup again in some other way. It was brief, but it happened. Likely the solder joint(s) wasn't the only issue.No way I was going to waster another second on it though, the joints caused the original fault so the video was done.