Broken PPUs/CPUs from China

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krzysiobal
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Broken PPUs/CPUs from China

Post by krzysiobal » Wed Feb 05, 2020 2:08 pm

A friend send me a few UA6528 chips (NTSC PPU), bought from aliexpress. All of them looks like brand new (no sign of soldering on legs, no scratches, even the legs are sticking out with the original angle from package). I wonder where did they get it from - as far as I remember, they are quite rare (in contrary to Dendy's PPU), and even if they appear in some consoles, they are soldered, not put in sockets. And if they were in sockets, the legs would have to be bent a little.

What a shame that every on them is broken. But they works, just the damage is quite interesing and different in every one of them. If the owner of console put invalid power supply, they would be deadly broken. Maybe some uncuccesful prototypes?

1 - invalid display of background, sprites displayed but with artifacts
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2 - sprites displayed with 2 vertical copies
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3 - invalid display of sprites & backgrounds,
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4 - colors are a litle oversaturated (tend to be more yellowish). Background on the start should be black, it is yellow. Permanently set red emphasion bit?
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5 - corruption of backgroundn after few second
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6 - artifact, weird checkboard pattern on some colors (like saturation)
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7 - totally messed colors
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8 - doesn't display background, only sprites
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9 - messed graphics
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He included also two CPUs, also broken in different way.
1. First one is UA6527P. Notice the weird small font on the package. The sound is weird (sometimes have slowdowns), or the music out of the sudden stops and another song from game is played (!)
After looking at the scope on M2, it has enourmous jiter and is not even close to the 1.7734475 MHz
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2. The second one is UA6527. Similar symptoms (shaking video, weird sound pitch). M2 is shaking too.

Hope the coronavirus not attacked those poor chips from inside.

MLX
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Re: Broken PPUs/CPUs from China

Post by MLX » Wed Feb 05, 2020 4:26 pm

I bet these just comes from an inventory of chips that did not pass QC. These just passed hands throughout the years but the information that they were all defective in some ways did not at some point. As a semi-related story, Team-Europe recently found a console that used a partially defective flash chip and worked around it by programming only the good cells. China recycles much more than one would think?

UA6527: the ink used is definitely not the usual one. It's especially more apparent on this page. Also I've never seen any clone use those chips with similar markings, so they're probably all defective?

pakosup
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Re: Broken PPUs/CPUs from China

Post by pakosup » Wed Feb 05, 2020 6:56 pm

It is hard to find working UA6528 on aliexpess. I also bought a couple from different stores and both were defective. So if you need ntsc chips it is better to buy famicom board in Japan.

tepples
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Re: Broken PPUs/CPUs from China

Post by tepples » Wed Feb 05, 2020 7:43 pm

Check your soldering on the pin that carries VRAM A2/D2 and PPU-to-CPU D2. (On a PPU with the same pinout as the NES PPU, these are pins 36 and 4 respectively.)

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aquasnake
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Re: Broken PPUs/CPUs from China

Post by aquasnake » Thu Feb 06, 2020 1:04 am

the powerful chinese recycling industry, especially in Shenzhen and Shantou

i purchased lots of flash chips that have not too good timing

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Punch
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Re: Broken PPUs/CPUs from China

Post by Punch » Fri Feb 07, 2020 7:22 am

I always wondered why some of my PIC16s have hard to read writing on the chips, turns out its a dreaded "recycled" chip. I might buy acetone later to see if there's original printing underneath.

This is what you usually get when buying ICs from china, aquasnake is correct. But at least they mostly work instead of just being defective batches.
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Ice Man
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Re: Broken PPUs/CPUs from China

Post by Ice Man » Fri Feb 07, 2020 7:57 am

Never had any issues from buying PICs or EPROMs from China at all.
I did have various defective CPU/PPU as well as clone MMC1/MMC3 IC (AX5904 and AX5202P).
Some did work, some had issues.

krzysiobal
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Re: Broken PPUs/CPUs from China

Post by krzysiobal » Fri Feb 07, 2020 8:28 am

My good advice is to not open disputes. At the beginning of my aliexpress adventure, I always opened disputes if chips arrived faulty and wanted refund proportional to the amount of faulty units.

Few weeks later when I wanted to buy anything, 50% of sellers replied to me few minutes after buying that `the goods are broken` and cancelled the transaction.

Probably I was marked as `demanding or problematic buyer` and the sellers notified each other about that.

Ice Man
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Re: Broken PPUs/CPUs from China

Post by Ice Man » Fri Feb 07, 2020 8:38 am

Yes, you do get flagged if you open too many disputes. Not a secret at all.
I did open only one or two (because they sent wrong item) and the sellers still ship to me until today.

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Ben Boldt
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Re: Broken PPUs/CPUs from China

Post by Ben Boldt » Fri Feb 07, 2020 12:43 pm

I open disputes all the time, probably 5-10% of my orders get a dispute. I have not noticed any problem yet. If you are already on the naughty list, then you may as well do more disputes, it can't really hurt at that point!

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