WTB Motorola 68882 50 MHz FPU

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pmjett's picture
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The title pretty well covers it. I'm trying to replace a missing PGA FPU on my 50 MHz Daystar accelerator. I realize that I might have better luck on an Amiga forum, and I have checked eBay Wink, but I was looking to see what I might scare up on the 'Fritter. I might be able to trade for it, PM and we can chat. Thanks.

mike

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grannysmith's picture
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IC-China

Keep your eye on http://stores.ebay.com/IC-China_Chips_Motorola_W0QQcolZ2QQdirZQ2d1QQfsubZ8133495QQftidZ2QQtZkm

He has no 68882s at the moment, but that is unusual.

de

Edit: The Forum software didn't produce a link from that URL, so I've left it in plain view.

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pmjett's picture
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Thanks!

grannysmith,
thanks for that. I don't think I have run across that storefront before, and it looks like they should carry them even if they don't currently. I emailed the owner to see what the going rate would be.

The ones I have seen on the net seem to run about $50.

mike

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From threads on the MLA, I ga

From threads on the MLA, I gather the FPU (and CPU) in the Dasytar upgrade cards were overclocked 40MHz parts, and that 50MHz parts were never produced. So keep an eye out for a 40MHz part and you might have more luck Wink

I've purchased a 40MHz 68030 (amongst other things) from IC-China, and they've always been delivered quickly and cheaply.

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grannysmith's picture
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That group opinion

may bear more relation to Urban Myth than reality, I am impelled to believe. Of the seven such cards that I have, and I refer only to the P33 cards, three of which are in IIci Macs, all are populated by the pairing of an MC68030RC50B with an MC68882RC50A. What about your card? I should suppose 100% concurrence in a random sample of seven to be conclusive. IC-China, although it cannot be verified from his current listing, had both chips in 50MHz earlier this year. See also [url="http://www.cpu-world.com/CPUs/68030/"]this listing[/url]

Oddly enough, my MC68030RC40B is paired with an MC68882RC33A (40MHz oscillator on the board), which could reflect a replacement by some intermediate past owner, but the pairing in a MC68030RC33B with an MC68882RC33A in my IIcx is congruent.

DayStar's good name may have been taken in vain. Regrettably, I cannot attest that from my experience with their heirs, XLR8, who resolutely refrained from reply to my emails about their ZIF carrier cards.

de

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pmjett's picture
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for the sake of completeness

I suppose that this thread now belongs somewhere else. (done! - eeun) I took a peep at both Daystar cards that I have. One is a P33 board, sporting a MC68030RC40B and a MC68882RC40A, with 40 MHz osc. The other is a P33 board, with a MC68030RC50B and a 50 MHz osc. I've seen 50 MHz 68882's on the net (usually for the Amigas, whose fans are even more rabid about preserving hardware than Mac folks) They seem to be pretty scarce. IC-China's web proprietor said that they have 68882's in about once a month. I tried to buy one on eBay from Sweden, but the price went to $90 - a place I will not follow. I can stomach $50. $90? No.

Could I overclock a 40 Mhz part 25%?.. meh. I could put a peltier cooler on the 68882. Wink

So, I'm watching IC-China, and hoping that a Fritterer will step up in the meantime.

thanks y'all.
mike

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Most of the older chips didn'

Most of the older chips didn't have heatsinks. Even a simple chipset sink might be enough to help the 40MHz part handle 50MHz if its in a decently fanned system.

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pmjett's picture
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seems like a stretch

eeun- thanks for moving the thread. It kinda outgrew a WTB by just a little bit.

Jon- Hmmm. Well, I have a 40 MHz 68882 (as noted). I suppose I could put an old fanned K6 heatsink on it and measure the temp somehow after cranking it up. I wish I had an IR thermometer. I did just take another turn through Google looking for possible vendors, and ran across a German seller that guaranteed 25 and 33 MHz parts at 33 and 40 MHz respectively. Those overclock percentages are in the neighborhood of 40 to 50, so maybe it's not too nutty.

If I get ambitious this week, I might take the se/30 down and try it out. Guess that rules out a "decently fanned system" Wink

thanks,
mike

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JDW
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MicroMac DiiMO uses 40MHz-rated chips clocked at 50MHz

I have posted a photo and explanatory text here:

http://www.flickr.com/photos/66071596@N00/478370007/

pmjett's picture
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right on.

So like most urban legends, there's a grain of truth. Obviously, 50 MHz parts were made; but if needed you can overclock 40 MHz parts for the job. (assuming the particular 68882 or 68030 you have is good enough for the task).

Nice pictures, JDW!
mike

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