Color Classic won't boot with FPU installed

[jimbojones]

I recently purchased a 16Mhz 68882 to fit in my Color Classic. Once installed though, the machine doesn't boot. Power comes on, but the screen is black and the hard disk doesn't boot.

I got hold of another 68882 chip, but that does the same thing.

 

Has anyone seen a similar issue?

[cheesestraws]

Do the 68882s work in other machines?

[Fizzbinn]

Are you sure you have the orientation of the chip in the socket correct? One corner is keyed/blunted on the chip and socket. I made that mistake with my LCIII at first, I guess I assumed it wouldn't pop in at all if it wasn't right but apparently I was forcing it in wrong and didn't realize it. The keyed/blunted corner is not super super obvious.

[mraroid]

I suggest checking if the chip is installed correctly as well.  

 

Mraroid

[jimbojones]

I found the attached pic somewhere on the net and installed the chip in the same orientation.

 

I can't be sure the chips are ok, but have no other way of testing them unfortunately. I have one more on it's way to test, so maybe third time lucky. The source is Chinese sellers on eBay selling them at around £2 each, so it may just be luck of the draw.

 

Edited August 20, 2020 by jimbojones

[Daniël Oosterhuis]

8 hours ago, jimbojones said:

The source is Chinese sellers on eBay selling them at around £2 each, so it may just be luck of the draw.

Yep, that's the problem here: Dodgy cheap chips from China, they'll bite you every time. 

[cheesestraws]

8 hours ago, jimbojones said:

I can't be sure the chips are ok, but have no other way of testing them unfortunately.

I'm also in the UK and have a working CC here.  If you post one to me (I'll post it back, obviously) I can test it in my CC here (which has an FPU in it already, so it's "known-good".

 

8 hours ago, jimbojones said:

The source is Chinese sellers on eBay selling them at around £2 each, so it may just be luck of the draw. 

Yeah, I wouldn't bank on getting a working one from that source / for that price.  Not that this is a particularly Chinese problem in and of itself, it just seems to be the currently fashionable locus of things being sold that aren't what they ought to be.

[jimbojones]

9 hours ago, cheesestraws said:

I'm also in the UK and have a working CC here.  If you post one to me (I'll post it back, obviously) I can test it in my CC here (which has an FPU in it already, so it's "known-good".

 

Yeah, I wouldn't bank on getting a working one from that source / for that price.  Not that this is a particularly Chinese problem in and of itself, it just seems to be the currently fashionable locus of things being sold that aren't what they ought to be.

Much appreciated, that's a great offer. I'll DM you if I decide it's worth it. I know it probably wouldn't help performance much, but thought I'd try it out of curiosity as it was only a few quid.

 

I presume these chips are just taken from e-waste, seems unlikely they'd try and fake them at that price, but you never know

[cheesestraws]

8 hours ago, jimbojones said:

Much appreciated, that's a great offer. I'll DM you if I decide it's worth it.

Yeah - it's probably not, honestly, given what you paid for them, but offer's open anyway .

 

8 hours ago, jimbojones said:

I presume these chips are just taken from e-waste

Seems likely.  I also remember hearing that there's some kind of multi-level fiddle where people contract long term to provide x number of chips which then become obsolete and unusable, so there's an industry providing chips that everyone knows will never actually be used under contracts that never should have been made, and a lot of those are fakes or known duds, which overflow into other supplies.   Under those circumstances, whether the chip works or not is probably a technicality...

[NathanHill]

I had this exact issue when I installed a FPU the wrong way. For one, I should have noticed how difficult it was to firmly place in there. But yeah the arrow and the dot should line up. I'll pull out my Color Classic in a bit and make sure it lines up with the image here. Once it was aligned, it booted fine.

 

However, I spent ~$30 on eBay for mine.

[johnklos]

You could tell better than we could, but is that a line on the m68882 right above the "MC68882"? If so, it may be a sign someone printed the numbers.

 

The last FPUs I got were so cheap ($7) and so new (2012) I thought they might've ended up being fake. It's good to read feedback on the sellers to see if anyone has reported non-working / relabeled chips.

[joethezombie]

That picture is of one of my boards, and I can assure you the orientation is correct and the FPU is authentic.  If you look at the package, and the board, you will notice the small registration marks (a dot on the board, an indent on the chip) that aligns.  Also the pin numbers around the socket will match with the pin numbering of the 68882.  If you purchased a 68882 for £2, I would highly suspect the chip.

[jimbojones]

Thank you everyone. The 3rd chip came and didn't work either.

 

I might give up, or look for a better source on eBay. 

 

Does adding an FPU to the Color Classic actually speed up much (JPG decoding in web browsers for instance)?

[mraroid]

16 hours ago, jimbojones said:

Thank you everyone. The 3rd chip came and didn't work either.

 

Hi...

 

I thought cheesestraws's idea was a good one.  That would for sure prove the trouble in our out of your motherboard.  Send him all three.

 

I never did try to run my CC with out an FPU.  Well, I did when it was all original, but I quickly added the max amount of RAM and a FPU.  It seemed faster to me, but it could have been my imagination.  We are dealing with very, very old and very very slow technology.  So anything to help speed it up is a good idea IMHO.   I read here that fake china FPUs were being sold on ebay and to watch out.  I bought what seemed to be a pull and an original FPU.  I dropped it in and it worked.  I have not looked back.

 

I would not give up on getting one installed.  Others here may know what software would take advantage of it.  I suspect spreadsheets, maybe Microsoft Word, maybe photos??  I just do not know.  But I would deffentally install one.  The price is right.

 

mraroid

[johnklos]

On 8/23/2020 at 1:57 AM, joethezombie said:

That picture is of one of my boards

Ah, yes - I see that OP said it was a picture from the Internet, not of the Color Classic specifically discussed in this thread.

 

It's a good reference picture - it's nice and clear - so I'd be interested to see a close-up, high resolution picture of the FPUs that jimbojones got that didn't work.

[jimbojones]

On 8/26/2020 at 2:50 PM, johnklos said:

Ah, yes - I see that OP said it was a picture from the Internet, not of the Color Classic specifically discussed in this thread.

 

It's a good reference picture - it's nice and clear - so I'd be interested to see a close-up, high resolution picture of the FPUs that jimbojones got that didn't work.

Please see attached. Sorry, my phone camera can't seem to focus on all three. The middle and right chips where from one seller, and the one of the left was from another.

[Franklinstein]

Even the one that does has focus looks a bit blurred. I'd suspect these were reprints. I wonder if someone could devise a sort of quick and dirty test for counterfeit '882s? Such as multimeter on pins 2 and 23 reads 2.8 ohms or something for an authentic chip. I'm not really an expert on these chips nor do I have enough stock to test something like that.

 

I bought a set of 20 FPUs off eBay a while back but they're later Freescale-branded chips and they're 40MHz-rated (bought as a lot so they could go in any Mac or accelerator from 16 to 40MHz). I have yet to try to see if they work so I'm hoping they do; otherwise I have 20 plastic squares that have no real value. I did hear once of someone who used to work at a recycling center and used a whole bunch of old x86 chips as tiles in a bathroom. Maybe they'd have use as an art project.

[Daniël Oosterhuis]

Unless I'm reading those datecodes wrong, I believe their format is YY/WW. So the middle and right one would be first week of 2019, and the left one 34th week of 2003. I would expect both supposed 2019 manufacture 68882s to have Freescale logos, if they were even still being made last year. However, I'm fairly sure at least those two, and if it's from the same source or at the same price, probably the 2003 one too, to be fake or dead chips, with new etching applied.

[bibilit]

I have a couple of bad SE/30 logic boards, having Maxell havoc issues. 

 

I am thinking about removing the FPUs for future use. 

 

Pretty sure are using the same overall size and compatibility, won’t have the same issues Chinese chips are displaying.  

[johnklos]

Later m68882 do exist, but 2019? Also, 16 MHz doesn't seem plausible at all. Anything made after 1990 is going to be of a mask that'll run at 40 MHz minimum, so who would want or sell 16 MHz FPUs?

 

Hopefully you find a good one in the UK.

[jimbojones]

Just to close this out, I got a 40Mhz one from a seller in the UK and it works perfectly. Seems there are lots of fakes from China on ebay. Seems mad considering how little they must make!

[cheesestraws]

Good to hear

[dan.dem]

@jimbojones Are you saying that a MC68882 labeled as 40 MHz works with 16? Interesting.

 

 

On 9/1/2020 at 9:14 PM, johnklos said:

16 MHz doesn't seem plausible at all. Anything made after 1990 is going to be of a mask that'll run at 40 MHz minimum, so who would want or sell 16 MHz FPUs?

I bought and installed a FPU advertised as 16 MHz in 1992 (roughly ~ 100 US$ then) into my original LC (very similar to a CC). I don't know about other manufacturers at that time but speaking about Macs the majority (if not all?) that could be retrofitted with a FPU had 16 to 25 MHz clock speed. Actually I would be happy if my 68882 would work with 20 MHz, I could transplant it into a IIsi.

 

About speed gains: If memory serves me, there are relatively few ones.

My main goal then was to make a relatively cheap 68020 machine more Mac II-compatible. I mostly succeeded since many Mac II-applications demanded a FPU, and were happy when they found one on the LC.

Some scientific software came both in FPU- and SANE-version (SANE is the set of software calls or functions - never sure what is what - for floating point operations). The FPU versions turned out to be about twice as fast as the SANE-versions. This was still a bit of disappointment for me, since a FPU call should be many multiple times faster than going the long way through a SANE call. And I remember how much faster a 8087 equipped IBM PC was compared to a plain one with a similar application type.

 

Many other software showed no speed gain at all, probably - I guess - as floating point arithmetic is usually avoided as much as possible because it is so slow. I'm, quite sure JPG compression is solely integer based.

[johnklos]

1 hour ago, dan.dem said:

Are you saying that a MC68882 labeled as 40 MHz works with 16? Interesting.

 

Faster marked CPUs will always run at lower speeds.

 

The performance difference between an 8088 / 8086 doing floating point and floating point on an 8087 is significant in part because floating point performance on the 8086 / 8088 is really bad. It's basically a souped up 8 bit processor that's register starved. Doing floating point in software on an m68000 is much faster, and faster still on an m68020, so the speedup of an m68881 is not nearly as significant as the speedup of an 8087.

[dan.dem]

@johnklos ad 1: I am aware this is used in modern processors tweaking their clock speed, but did not know this works with old processors too. I always thought they are phase optimized for a frequency on a deep hardware level.

But what makes me wonder is why this isn't true for many RAM modules. At least modern (DDR3) faster labeled DIMMs "usually"/"often"/(or just) "in my case" don't work with slower boards. But there may be different reasons why it didn't work (at least voltage was ok), and I don't have any deeper understanding of RAM-technology (unlike some brilliant folk here who are designing SIMM sticks). But we probably stop here for avoiding to become totally off topic.

 

ad 2: Yes, this should be the main reason for the disappointing speed gain. And I can imagine that the 68020's little instructions cache makes a noticable difference as long as the data to be processed is already in one of its registers. Thank you for pointing this out.