I’m currently working on a YM2149/AY-3-8910 sound card project for the RC2014 computer. Because of that I’ve been trying to obtain YM and AY chips from various sources. These ICs aren’t available new, so any ICs for sale must be either NOS or pulls.
So far I’ve bought chips from 4 suppliers in China, one in Italy and one in the UK.
The chips from China were all sold as new but they are all clearly pulls with solder on the chip pins and signs of use. Some of them also have markings which don’t look like those that I’ve seen on pictures online, on chips bought as used arcade machine pulls or in computers I’ve owned (Spectrum +2, Atari ST)
I don’t mid them being 2nd hand, but non-original markings isn’t what I’m after.
The following artefacts may be seen on the remarked ICs:
- Texture of the plastic on the top different from that on the bottom (smoother, cleaner, no scratches etc)
- Moulding marks and pin 1 identifier dimple are shallower than they should be due to the sanding
- Typeface of text is different from that used by original manufacturer
- Many chips obtained at different times from different suppliers all having the same date code, suggests there is some central source remarking these.
- Top edges of IC package are squarer than the bottom due to the sanding
I’m wondering what the motivation for attempting to remanufacture these chips and sell them as new is? They only sell for between £1 and £3 at the moment anyway (guessing this may rise as supplies dwindle). The other thought is that the newer variants that are still being manufactured (Winbond WF19054, JFC 95101 and the File KC89C72 according to Wikipedia) are being resurfaced to be more desirable. That seems unlikely though as you’d imagine those chips to be unused.
Here are some pictures of the chips I believe to have been remarked:
Notice how the top is very black and clean compared to the grubby bottom and sides, and the pin 1 marker dimple is shallow.
Another one where the texture of the top and marking seem wrong.
I’ve only seen YMs like this one in eBay auction listing pictures.. Once again top markings seem too “fresh” compared to the rest of the chip
This is the cracked YM that I received. This ones markings may indeed be legitimate
These are the definitely legitimate markings:
Apologies for the low quality pictures, but I don’t have a macro lens for my main camera so had to use my phone.