Moonbase Arcade Restoration - Gone Wrong

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[sw]

I'm a TV technician - I started working on CRT sets (including monitors) in the late 1970s and continued into the early 2000s. First thing I will say is don't beat yourself up for installing the replacement IC backwards. I have done that a number of times myself, it's easy enough to do!
As for the failure of the replacement, there's a few things I would be checking. The first is the DC resistance of the vertical coil on the yoke. It should be between 2 - 7 ohms (and 4 - 15 mH if you have an inductor tester). Also check it for shorted turns. That will kill a vertical output IC in short time.
Next check the voltage rail going to pin 2 or 10 - should be within the range of 9 - 18 volts (20 volts absolute max).
It is possible (can't be ruled out) that when you powered the board up with the IC installed backwards it compromised it. The results of such a situation can't be predicted. I have had ICs survive just fine, others fail immediately (let the magic smoke out) and some which worked fine for a while only to die further down the track.
Those dark stains on the original chip are indicative of an IC that's been running really hot. I suspect the thermal connection to the heatsink wasn't great. It needs to be very well thermally bonded. Use the white thermal paste.
Lastly I would question the authenticity of the replacement IC. Where did you source it from? If it's from eBay or Aliexpress etc it's likely a chinese fake. They'll often work for a while then go toes up after a period (as this one did).
I would attempt to find a genuine IC from a known seller to be absolutely sure it's a good one.
As far as I can see, the KA2130 is a pin-for-pin replacement for the uPC1031H2.
Looking forward to part 2 of this saga.

[sage_x]

This is just an idea, and probably odd, but hear me out.

You remember how the sticker on the side said it is made for 100V 50/60Hz? Well... Everything on it indicates it definitely was made for the Japanese Market, and maybe the place this has been in before, actually ran it at 100V AC.

My guess would be, use a multimeter, and look up the pin out of the IC you replaced, as well as some other connections. The parts can't exceed certain voltages. If they do, the power supply gets too much power, and doesn't step it down properly.

It could also be a faulty power supply, but given this machine has a sticker on it that says "Made in Japan" and has a Japanese start button, I would presume this really was made for that very specific voltage and was never changed.

The arcade this has been at, might have run it at 100V, then they sold it or got rid of it, someone else tried to use it at 120V, which broke it, so they got rid of it and eventually you got it.

I just believe, it certainly wouldn't hurt to try and check some DC voltage readings on the board, to see if that is your issue.

Hope that helps ^^

[BrendanWeibrecht]

As a software developer, I absolutely do not envy the 40-minute feedback cycle you had here! I really struggle beyond like 20 seconds, haha

[Micmeat]

The rolling mode has to be one of the most innovative difficulty toggles of all time.

[holymackerel]

I always appreciate when people include their hardships and mistakes. It adds authenticity.

[BoshMind]

For a clone of Space Invaders, the machine is nearly identical to a real one. I fixed one up a few years back and the internals are nearly 1:1.
Although mine had a breakup letter in it instead of a dime lol.

[fixitalex]

Don't worry about mistakes David! As my professor used to say "Any experience is experience" Try to check signals around vertical chip with oscilloscope. It maybe over-voltage or problems with driving signal.

[fitfogey]

I personally love your humility in including the mistakes. Nobody is perfect. It gives us an understanding in the substantial time it can take to try and get something to work. I really value your channel.

[michaelbutta]

@The 8-Bit Guy,
I don’t know if you will ever see this comment David but I want it said regardless: I THOROUGHLY appreciate your videos, ESPECIALLY the moments in which you discover an error in the process. It’s largely because of the honest, detailed record of your process in refurbishing electronics (a discipline of which I only have a passing interest) that I have followed your content over the years. Your candor and transparency are refreshing and I wouldn’t have you change a thing.

Thank you sincerely for the effort you invest in my entertainment!

[GeekmanCA]

IT Pro here – Anyone pointing and laughing at a small mistake after weeks of gruelling troubleshooting has never been through a frustrating troubleshooting process. That's life in tech. There's a fine line between people jokingly taking-the-piss at you for putting a part in backwards versus acting like that's any reflection on your actual ability or competence.

[eDoc]

I think it's a power supply diode, here's why: From my experiences with TVs I can tell you have 60Hz ripple in the monitor circuitry. Since the fault is causing decreased picture size it's most likely in the power supply circuitry. The odd thing is the monitor has a full bridge rectifier so regulation issues _should_ be manifesting at 120Hz. One explanation is that one of the diodes in the rectifier is intermittently failing open. Since Adrian was testing with DC instead of AC input such a failure likely would not have shown up in his testing.

[Xsses]

You have no idea how important your videos are. You really keep the spirit of those who have restoration problems like you. Sometimes fixing something old is hard and seeing someone having similar problems means that at least I am not the only one.

[Psychlist]

I'd rather see mistakes and folks own up to it, rather than see a problem, and then there's a magic cut and it's fixed without any discussion. Thanks for keeping it honest.

As to the unit itself: I recommend checking the output voltage of that power transformer. I have a lot of old synths from Japan, and they work on US voltage, but heat up way more than they should (some have tuning issues if run on US voltage). It's really a good way to have them fail early, and maybe toast some unobtanium. If the voltage coming out of the transformer is too high, just run it off of a 120v->100v step-down transformer external to the cabinet, or maybe even down in the coin drawer.

PS: That pic at 19:43 is, erm "inspired", right from early Yamato/Star Blazers. It's the Comet Empire.

[barberamixing]

Have you considered checking for the proper output voltages from the power supply? Not only to check for functionality but it would also tell you if it really is a 100v unit or not. You mention it burning out chips, maybe because the voltage is too high and you do need a step down transformer. Love your stuff! Hope you get it figured out.

[appliedengineering]

Dave. That putting the IC in backwards was a honest mistake on your part. In my decades of working with electronics. I can tell you right now that the fact that that board was designed to hold that chip in backwards was a violation of industry standards. Any time you have an electronic component that need mounting to a heatsink. You always mount the component with the label side facing the same way as the mounting screws. I'm surprised that you haven't came across some DIP IC sockets mounted in backwards on some of your old computers you work on. I had this happen to me a few years ago when I ended up frying a very expensive microprocessor because the service tech before me decided to put the IC socket in backwards on the board. Had I look closer and saw the silkscreen markings or remembered the orientation that the old IC was in. I would've spotted the mistake.

[skittstuff]

Honestly, I prefer watching people make mistakes and figure out what went wrong. The learning process (and accepting that it's okay to make mistakes) makes you seem more human and humble. Nobody is going to be perfect. And certainly to an outsider who doesn't fix electronics like you, I think you're doing a fine job. So fun to watch while I'm taking boring school notes!

[Hidyman]

20:03 I believe there is a rubber bushing inside where the shaft comes through. You could probably find a silicone (or rubber but it would be less durable) hose of the proper diameter to replace the bushing to firm it up. There also would most likely be a washer at the end. You could check the stick on the other side to see if that is the case. At worst you could use an angled rubber washer that would commonly be used in an old school water valve (backed by a small fender washer or two.)

[Dukefazon]

Check the output voltages on the PSU and check the Vcc and other voltages on that part you replaced. My only guess is that the PSU output is too high and it's quickly wearing out that part.

I've seen Adrian's video on fixing the part, it was an interesting piece. Yeah, it's crazy, the bigger your audience the more likely it will draw in jerks. You did good, but it's important to take several pictures befure you disassemble stuff so it will help you puting stuff back together. Sometimes you think you'll remember where each screw goes but it's easy to forget little details.

[idormain]

Personally, I think showing your mistakes is a sign of honesty and integrity. Getting it out there is a way people learn. Good on you for keeping your mistake in the video. Anyone who is critical of you for making a mistake simply isn’t grounded in reality. Great video, love your work!

[Jordan-ezgn]

These restoration videos are so interesting and weirdly therapeutic. People online have a tendency to be overwhelmingly negative, don't let it get ya down.