zigzagjoe
Well-known member
Compiled this data earlier today to assist in determining which 68882s are fake (sanded off and remarked) and which are legit. It's usually quite obvious by poor quality of markings, or old masks with new date.
Date codes are the last 4 digits of the last line on the CPU center. Given a date code of QEJQ9019, this is year 1990, week 19
Some guidelines:
Here is the compiled data so far, in order of age of mask. This was sourced by looking at vintage equipment with 68882, and other verifiable sources - ie. not something purchased by hobbyist off ebay. Not at all complete, and it's obviously harder to get verifiable sources past 1994 or so given it was an obsolete part by then.
Full data: https://docs.google.com/spreadsheets/d/1z4L56dWWPeJ-x0bQX8XpUEkuwVoOnD27/edit#gid=261616021
Regarding clock frequencies, anything 1C12R or newer should do 50mhz without problem regardless of markings. OC35H should be able to hit 50 usually as well, but not guaranteed. The takeaway here is with most masks being good for 50mhz, even fake ones have a pretty decent chance.
Date codes are the last 4 digits of the last line on the CPU center. Given a date code of QEJQ9019, this is year 1990, week 19
Some guidelines:
- Markings should be well defined, the text fine and the logo legible
- If the text is thick, it's probably fake.
- no logo = fake!
- Font should be closely spaced, narrow and taller characters
- Freescale logo only on chips 2005 or newer
- Older masks will not significantly overlap years with a newer mask
- ie. OC35H made in 2005 is fake
- Markings will not be removed by acetone
- PGA: some missing pieces of letters is acceptable
- PGA: will have engraved text on the ceramic that corresponds to actual mask
- PGA: country of origin usually on ceramic (uncommon to be on the gold)
- PGA: gold Y on copper should be bright, not dark
Here is the compiled data so far, in order of age of mask. This was sourced by looking at vintage equipment with 68882, and other verifiable sources - ie. not something purchased by hobbyist off ebay. Not at all complete, and it's obviously harder to get verifiable sources past 1994 or so given it was an obsolete part by then.
Full data: https://docs.google.com/spreadsheets/d/1z4L56dWWPeJ-x0bQX8XpUEkuwVoOnD27/edit#gid=261616021
Regarding clock frequencies, anything 1C12R or newer should do 50mhz without problem regardless of markings. OC35H should be able to hit 50 usually as well, but not guaranteed. The takeaway here is with most masks being good for 50mhz, even fake ones have a pretty decent chance.