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Sourcing Legit MC68882 FPUs - Data
- Thread starter zigzagjoe
- Start date
Yep, looks plausible to me.
Here's some pics of a batch of FPUs I received from eric woo. Unfortunately, the faint ones didn't capture very well. All legit, but I haven't listed in the sheet yet. I just ordered another 200 from him so hopefully should have some more datapoints soon.
It's more that I never want to solder a SMD PLCC socket ever again. Besides preserving my sanity, I've found that it's far nicer to folks to buy an accelerator with the FPU installed and fully tested rather than have to try to chase one down themselves. Currently, there are essentially no reliable sources (eric doesn't usually sell these) aside from some US based obsolete part dealers that are wildcards.
Looks fine to me too.
An important note, though, for most cases even a remarked FPU is fine if you're only asking 16mhz of it like in a reloaded board. They're still 68882s, and even the early masks could do that. It's just when you want to run it at 50mhz that it becomes a huge problem.
Cool beans. Date seemed plausible to me. Will have to give it a go. Want to check the source before messing around. I don’t think I’ve seen a FPU lower than 16mhz so if this actually runs at 25 then I’m cool with that.
I've only seen it on the very early and very late ones like you have. Yours will happily do 50mhz, FWIW; the rated speed means essentially nothing on these.
My best guess: Motorola made a lot of early 16mhz parts, but device manufacturers rapidly wanted faster and faster FPUs, so Motorola ended up sitting on a stockpile of 16mhz FPUs. I'm sure there were a few manufacturers of LTS (long term support) devices with stringent compliance requirements (aerospace, military ?) which require using the original P/N to avoid having to recertify their device with the faster parts but different P/N. Eventually the stockpile dried up and those companies still required 16mhz parts, so motorola marked some as 16mhz to satisfy their needs.
Could be completely wrong, but that's just my thinking.
That makes sense. As manufacturing got better there would invariably been less lower rated mhz FPU chips binned.
Personally I’m a little suspect of anything rated at 33mhz. On Alliexpress there are only 50mhz MC68030RC50 PGAs which seems a bit dodgy. The only reason I’m looking at those is because my vinegar bath lifted the silkscreen off my SE/30 original gold CPU. I know I should have removed it before doing so. Even if its socket is used for an upgrade it’s not perfect anymore :-/
Buying off Alli requires a lot of scrutiny. Eric seems like a much better source. If you haven’t bought them all already :-D
That would be cool for geographically close groups of folks otherwise shipping wouls kill any savings. Still a good idea. Definitely thinking about what I may need / want in future while they’re still around.
@Iesca My theory is that they bulk process the parts for resale regardless of speed. Same for 68040s. They're just pulled and dumped into a bin, then processed and cleaned, then re-screened with all the same info. It's cheaper to deal with the odd return than it is to hire additional people and spend additional time and money sorting & testing.
And with up to several months between returns and replacements, is anyone going to bother?
And with up to several months between returns and replacements, is anyone going to bother?
Unfortunately, for the CPUs that are most desirable there isn't really room for any savings. No $25 68040s here, I'm afraid. 68030s are thankfully less in demand so working with eric has been fruitful so far as he can meet the requirements on masks I need.
Yeah, eric is the only one I will buy PGAs from, aside from US sellers not in california. For some reason a lot of chinese sellers will advertise an address in china and drop ship. Absolutely don't buy chips with any kind of demand from Aliexpress or UTSource, they have no controls to make sure chips are not remarked/fake.
Yeah, that was my question too... why? Of the 40 remarked FPUs I evaluated, all were marked as 25mhz. None of them were grossly dysfunctional (Ie. not a 68882) but instead were just too slow for the frequency I was asking of them.
I've read that there's a belief that the market demands (and maybe this is true in China) new-looking chips, and the salvagers don't really know what the markings mean so they just pick something to paint on it and call it a day. Even when that lowers the ratings...
I am now quite sick of looking at 68882s. I don't have any doubts about the legitimacy of these. I don't feel like entering every single one of these into the spreadsheet so instead I took pictures.
Here are some high level observations:
Here are some high level observations:
- New MC68882EI sufffix, found only on Freescale marked parts.
- Not sure what this means, all late production parts.
- I've never seen even heard of this before!
- Earliest marked freescale part dates from 2004.
- Quite a variety of markings applied
- Definitely less consistent than I was expecting.
- In order of most common to least: 25 mhz > 16 > 20 > 33
- no 40mhz. Maybe they were culled ahead of time?
- Even the earliest 1C12R chip has no issue at 50mhz.
- Earlier 1C12R packages are noticeably lighter in color.
Attachments
Absolutely remarked. But, if it passes Mac Test Pro, it should be fine.
Must be one of the classier remarked parts, since it passed the CRC Lectra Clean solvent test and it looks to be laser etched.
I replaced the CPU as well because the original 25 MHz 68030FE25B ran burning hot and was unstable. Even at its stock speed it ran burning hot for the 30 years that I've had it. This part, whatever it is, only gets warm.
I replaced the CPU as well because the original 25 MHz 68030FE25B ran burning hot and was unstable. Even at its stock speed it ran burning hot for the 30 years that I've had it. This part, whatever it is, only gets warm.
As part of my new batch of FPUs I've found that early 1C12R chips may not always do 50mhz. I suspect they're probably fine for 33mhz but probably should avoid if 50mhz is the goal. I've got 2.5 tubes worth to test and will return with results.
The odd part is I've never encountered this before, however I am not sure how many 1C12R chips I used prior this point. I'm quite sure that later 1C12R FPUs would do 50mhz, makes me wonder what changed as lithography ought to have been constant and without any process changes.
The odd part is I've never encountered this before, however I am not sure how many 1C12R chips I used prior this point. I'm quite sure that later 1C12R FPUs would do 50mhz, makes me wonder what changed as lithography ought to have been constant and without any process changes.
