Please forgive the slightly scattershot nature of this assortment, since I was hesitant to sacrifice more than a few working chips.
First, the clones...
Unknown CPU with /16 CLK DIV
This was a working CPU with a verified /16 clock divider that had been re-marked via laser as a "UA6527" which it obviously wasn't because it didn't have a /12 clock divider. I had assumed it was an older-style UA6527P, but the die markings make me wonder if it wasn't a UMC chip at all though!? They're unlike any other that I observed, and they were on the very very edge of the die:
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+HN1225002A
*M* HMC
AA AAA
This was a working CPU with a verified /15 clock divider that had also been re-marked "UA6527" but obviously wasn't for the same reason as above. I suspect that it is actually a later-style UA6527P:
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UMC C M
B6167F
1989.09
This was a working CPU with a verified /16 clock divider and what appeared to be original chip markings that said "UA6540 8833S" on the top. I was curious if this would end up being the same die as a /16 UA6527P. I'll need to crack open a non re-marked UA6527P to check for sure.
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UMC
1987
C M
TU6142
I wanted to try a UA6528 from one of the revisions that has constantly been non-working for me, with all kinds of crazy video artifacts, mostly because I was curious if the dies between working and non-working ones would be different at all. So this was what appeared to be a UA6528 with original chip markings and a "CS" designation:
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UMC
TU6133F
C M
1988
This was a working UA6528 chip with apparently original markings and a "CA" designation. As you can see, it did in fact have exactly the same die as the "CS" version above, so the difference in reliability/functionality is not related to the die itself.
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UMC
TU6133F
C M
1988