nicole
Gun-headed
Posts: 50
Fave PCE Shooter: Magical Chase
Fave PCE Platformer: Legendary Axe II
Fave PCE RPG: Ys III
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Post by nicole on Jul 29, 2020 21:45:36 GMT
Recently rolled the dice and got a SuperGrafx in unknown condition. Unfortunately, as usual, "unknown" means "not working".
I had to resolder new wires to the 9V power jack board; after doing that, it won't play any of the small number of PC Engine games I've tried (some giving a white screen, some giving white then black). I don't have any TurboGrafx-specific games, but I was able to get my Turbo Everdrive (which did the white then black) to load Daimakaimura (by setting it as the last-played game on my working PCE), and though no video came out, I did get audio and glitchy rather than no video.
All of this testing was done with a Turbo Duo composite lead plugged into the composite jack. I haven't tested the expansion port; I have a booster coming from Hong Kong for that, I'll definitely try that once it arrives. (Though in the current climate, who knows how long that will take)
It seems like there might be a tiny amount of corrosion on the pins of one of the HuC6260s (the one further to the rear of the console), but all the continuities I've been able to trace check out, and heavy cleaning didn't help, so I'm not sure if that's the problem.
Is there a schematic or... any resources out there at all on troubleshooting the SuperGrafx?
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keithcourage
Punkic Cyborg
https://www.facebook.com/turbografxfan/
Posts: 230
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Post by keithcourage on Jul 30, 2020 6:23:32 GMT
Plain white or black screens is a bad sign. Usually means a faulty chip inside the system or cracked motherboard near one of the Hu card slot Support posts.
There is still a small chance the card slot pins could be dirty. So wipe some rubbing alcohol on the pins for a hu card then insert it in the system a few times.
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nicole
Gun-headed
Posts: 50
Fave PCE Shooter: Magical Chase
Fave PCE Platformer: Legendary Axe II
Fave PCE RPG: Ys III
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Post by nicole on Jul 30, 2020 13:27:31 GMT
It seems like if the music plays in Daimakaimura then the HuCard slot should be alright? But there is some white residue around the HuCard slot. (Also, the factory bodge wire connecting to the expansion pin fell off, but I don't think that would cause this issue?)
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samiam
Punkic Cyborg
Posts: 100
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Post by samiam on Aug 1, 2020 2:47:16 GMT
I've spent a lot of time arguing with my Supergrafx.
Cleaning the heck out of the pins is a really good idea. You want to be able to put an alcohol-wetted Hucard in and out of the slot a few times, then rub the Hucard contacts with a q-tip and not see any grime come up.
I also find that Hucards tend to make better contact when I have the card scooted as far over to the left (my left) as possible.
If you'd like to post a picture of the corrosion you see on the board, I'll certainly offer any thoughts I have. Just the other day, I fixed a remote control PCB that had damage from a leaky battery. Toothbrushes are useful for this kind of thing.
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Post by SignOfZeta on Aug 1, 2020 16:08:22 GMT
If the real HuCARDs you have don’t work but the Everdrive (which is decades newer and with much shinier contacts I’d imagine) does work (barely) then I would for sure concentrate on cleaning the card slot and also all your old HuCARDs.
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nicole
Gun-headed
Posts: 50
Fave PCE Shooter: Magical Chase
Fave PCE Platformer: Legendary Axe II
Fave PCE RPG: Ys III
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Post by nicole on Aug 6, 2020 21:15:22 GMT
To anyone who sees this thread because they're having similar issues: I traded the machine to a local repair person in exchange for taking a look at my Duo, he was able to find that the corrosion, caused by leaking capacitors, had destroyed traces on the video memory bus going to the top HuC6260, and a botched repair attempt on top of that had mangled the pins somewhat.
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keithcourage
Punkic Cyborg
https://www.facebook.com/turbografxfan/
Posts: 230
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Post by keithcourage on Aug 7, 2020 20:34:34 GMT
Weird, this is the first I've heard of leaky caps being inside of a supergrafx.
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Post by dshadoff on Aug 8, 2020 0:56:33 GMT
I've heard of cases where people have done a "presumptive" capacitor replacement and used poor-quality ones; this is a possibility.
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czroe
Deep Blooper
Posts: 45
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Post by czroe on Sept 8, 2020 1:06:07 GMT
I've heard of cases where people have done a "presumptive" capacitor replacement and used poor-quality ones; this is a possibility. This is why I have been staunchly against shotgun recaps on systems that are running find and have no history of bad caps, like N64 (excluding the power supply) and NES (excluding the Alps or Mitsumi power/RF boxes). That said, I was investigating a late model Pikachu N64 the other day which had no audio. I swapped out the AMP-NUS chip and two capacitors but still had no audio. I slipped when measuring voltages and shorted 12v into AMP-NUS pin 2 which was also connected to a capacitor nearby (one I had not replaced yet). Audio instantly returned! I doubt it had anything to do with sending 12v into the AMP-NUS chip since I had just swapped that so I must've shocked that capacitor back to life. Also, the capacitor was rated 25v so I should not have hurt it. Caught the whole thing on video too, which I uploaded to Facebooka couple weeks ago. Anyway, I guess it's possible that the very last N64s were made with RoHS (lead free/Pb-Free) caps and may be more prone to failure than earlier ones. This was a NUS-CPU-09 or NUS-CPU-09-1 board from a Japanese console with the stamped heat sink (no screwed-on heat blocks). I have another Japanese Pikachu console with a CPU-05 board and the older heat sink design so it seems these were produced over a very long time in Japan!
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Post by dshadoff on Sept 8, 2020 5:24:45 GMT
Capacitors were getting better and better until around 2001 or so, when a Chinese company decided to set up a capacitor factory, stealing the recipe for the electrolyte from another company... Trouble is, they failed to steal the recipe for the stabilizer, so the capacitors all started failing within about 2 years, causing huge problems from certain PC motherboard makers and consumers (as well as other consumer electronics and other things).
If you're going to switch out capacitors, you should use parts from a reputable manufacturer, obtained from a reliable supply chain in order to avoid that kind of problem.
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czroe
Deep Blooper
Posts: 45
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Post by czroe on Sept 8, 2020 14:25:11 GMT
Capacitors were getting better and better until around 2001 or so, when a Chinese company decided to set up a capacitor factory, stealing the recipe for the electrolyte from another company... Trouble is, they failed to steal the recipe for the stabilizer, so the capacitors all started failing within about 2 years, causing huge problems from certain PC motherboard makers and consumers (as well as other consumer electronics and other things). If you're going to switch out capacitors, you should use parts from a reputable manufacturer, obtained from a reliable supply chain in order to avoid that kind of problem. Yes. The Capacitor Plague, as it became known. In particular, I remember IBM and Abit getting raked over the coals for this before the full story was known. My understanding is that they needed a new RoHS-compliant formula to stay in business. An engineer left a Japanese company he worked for with half of the new RoHS reformulation. He partnered with someone in China to sell it resulting in millions of caps from Taiwan under many different brands (some counterfeit)... without the stabilizer. The thing is, the stabilizer only explains why those were failing within a year or two, not why even quality capacitors in general have been less reliable ever since. That comes down to compromises for RoHS compliance. Obviously the previous formula had some performance, stability, or cost advantage or they would have already reformulated. Just like The Capacitor Plague was touched off by an industry shift to RoHS components, past waves of bad caps can also be traced to other industry shifts. For example, the Duo, Super CD-ROM², and Express / GT caps were a big issue while their Shuttle, CoreGrafx, and CoreGrafx II from the same period never had such issues. Why? I think it's because there was another big industry shift to SMD electrolytic caps, which were used for the problematic systems while the others used traditional caps. Manufacturers were scaling up as consumer electronics began to use them more and more, so these growing pains were inevitable. IOW, it wasn't just cheap SMDs, but as the better manufacturers figured out how to produce better seals and packaging, SMD electrolytic caps matured. That's why the Duo-R, Duo-RX, and so many other '90s consoles never had those issues (PSX, N64, etc). Of course, the crappy caps continued to be unreliable, such as those in N64 PSUs that weren't made with quality Japanese caps. Each wave of particularly bad caps was precipitated by an industry shift in capacitor design. There's a good chance that a Nichicon thru-hole non-RoHS cap from the late '80s or mid '90s is going to outlive quality RoHS caps you could replace it with today, so an unnecessary recap job could actually reduce the life of a device.
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Post by SignOfZeta on Sept 8, 2020 15:28:53 GMT
I can’t imagine why someone intelligent would do $50 worth of work on a system and use “cheap” caps. Considering the caps needed for a SGX, the difference between cheap and good is like...is it even $2? It would be stupid, just like the bad work they supposedly did and the choice to preemptively do it...all bad moves, from the sounds of it.
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Post by dshadoff on Sept 8, 2020 16:07:21 GMT
Well, there are a lot of people who seriously don't know that there is a difference between 'good' and 'bad' capacitors, or what the difference might be.
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czroe
Deep Blooper
Posts: 45
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Post by czroe on Sept 8, 2020 17:02:38 GMT
I can’t imagine why someone intelligent would do $50 worth of work on a system and use “cheap” caps. Considering the caps needed for a SGX, the difference between cheap and good is like...is it even $2? It would be stupid, just like the bad work they supposedly did and the choice to preemptively do it...all bad moves, from the sounds of it. Right, but even the good RoHS caps are possibly going to have a shorter life than the life remaining in the original non-RoHS caps for some things, so replacing them for no reason, even with quality modern caps, could conceivably reduce the life. That's why it makes no sense to preemptively recap your average TurboGrafx-16 or SuperGrafx. I say this despite having found recent evidence of an N64 with a failed cap: imgur.com/gallery/tSAmNEiIt was an extremely late revision and component suppliers were likely in full-swing for the RoHS transition by that point.
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Post by SignOfZeta on Sept 8, 2020 17:41:51 GMT
I agree with that. My Marantz 2235 still plays loud, more or less daily, all original caps...from 1972. There is a fad to refurbish and Craigs List off these old receivers and it depresses me. Sometimes they even “update” the original bulbs with LEDs and that’s truly nauseating. If it doesn’t “warm up” then leave it alone!
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