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Post by paulpsomiadis on Sept 3, 2006 19:58:26 GMT -5
Here ya' go! cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=6885545634&rd=1&sspagename=STRK%3AMEWN%3AIT&rd=1Bearing in mind that this was the ONLY 387 compatible co-pro. available on eBay at the moment! Keep looking ('any country/region' search on eBay) and you'll eventually have one turn up... ;D Search keys that are useful are... Cyrix Fasmath or CX-83S87 ...for Cyrix co-processors (although the SX variant is rare!) and IIT 3C87SX for the more common IIT co-processors. GOOD LUCK!
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Post by paulpsomiadis on Sept 7, 2006 11:18:11 GMT -5
Well, the GOOD news is that my 387 co-pro arrived... ;D ...BAD news is that I have no spare crystal oscillators! AARGH! Anyhow...I ordered a batch of 80MHz oscillators (this will match the one for the 40MHz CPU and esentially 'overclock' the co-pro) I also ordered some 66MHz crystals too (this will 'underclock' the CPU and match it to the 33MHz of the co-pro) Problem is that they are (once again) only available from eBay U.S.A. - so I'll be waiting another couple of weeks for them to arrive... I'll keep you all updated!
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Post by GiGaBiTe on Sept 8, 2006 18:28:56 GMT -5
Why not just buy a variable oscillator? That way you would be able to change the CPU speed on the fly without having to worry about damaging the motherboard. There is a kit for macintoshes that has one, and It works quite well.
I guess the hard part would be finding one in the range of 66-100 MHz.
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Post by paulpsomiadis on Sept 9, 2006 11:03:21 GMT -5
Heh - didn't know about that! But I'd rather have FIXED crystals that I know will work. Besides, it's done and all I have to do is to wait for them to arrive now... Anyhow - I'll let everyone know how it goes when they arrive... ;D
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Post by paulpsomiadis on Sept 13, 2006 10:38:39 GMT -5
WOOHOO! My 80MHz crystals arrived... ;D AND IT WORKS! At 40MHz no less! I wasn't sure that the 387 33MHz would run at 40MHz - but the system seems perfectly stable. @tom Maneiro - I had to buy the 80MHz crystals in BULK... ...so I have 19 of them 'left over' if you'd like me to post two or more of them to you for 386 'overclocking'. Let me know and we can discuss the details via PM... ==EDIT== Hmm...it seems my SCSI card is incompatible with Win 95 OSR2...so I'm going to have to find another way to get a CDROM in there...
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Post by GiGaBiTe on Sept 14, 2006 20:15:30 GMT -5
I wouldn't bother with SCSI that old, as the IDE on those old 386's and 486's is probably the 16.67 MB/s while the old 50 pin SCSI is only 5 or 10 MB/s. Now try to run the 386 at 80 MHz need a heatsink and fan though.
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Post by paulpsomiadis on Sept 15, 2006 10:00:08 GMT -5
Uh huh - and where exactly am I going to find a 160MHz crystal from?
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Post by GiGaBiTe on Sept 15, 2006 18:41:27 GMT -5
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Post by paulpsomiadis on Sept 16, 2006 19:29:34 GMT -5
Okay - from the list you provided, the following would be possible 'compatible' crystals... 1) FMOC71 2) FMOPCL/FMOECL Chances are it's more likely to be No. 1 than 2, as the FMOC71 are CMOS compatible. ;D I'm not really bothered about O.C. ing my 386, as it was my first ever P.C. and I want to keep it in a working condition... (yeah, I just stored it in an old cupboard and decided to drag it out recently to renovate the sucker...) I still remember the first time I played 7th Guest on this machine, which I might do again soon... (of course, I use the Windows version now...) Anyhow, I'm gonna have to get a new SCSI card for my CDROM first...off to eBay again! ;D By the way GiGaBiTe - it looks like your avatar is broken! (at least I THINK it's your avatar, it's broken so I can't tell! LOL!) ;D
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Post by GiGaBiTe on Sept 18, 2006 4:26:11 GMT -5
My avatar has been broken for many months now, I just never bothered to fix it.
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Post by paulpsomiadis on Sept 18, 2006 8:45:33 GMT -5
I'm glad you did though - it's one of the better ones I've seen...
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Post by Tom Maneiro on Sept 18, 2006 14:12:26 GMT -5
Nice to hear that your overclocking mod worked fine..
I need the following things: 1)a crystal 2)a crystal socket 3)and solder/desoldering skills (plus soldering equipment).
1) and 2) are easy to get (although the socket may be a tough one), but... where do i get the skills? I don't want to ruin a perfect board? Plus i don't have a way to get a copro...
Someday...
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
Posts: 1,301
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Post by oompa loompa on Sept 19, 2006 23:02:14 GMT -5
Nice to hear that your overclocking mod worked fine.. I need the following things: 1)a crystal 2)a crystal socket 3)and solder/desoldering skills (plus soldering equipment). 1) and 2) are easy to get (although the socket may be a tough one), but... where do i get the skills? I don't want to ruin a perfect board? Plus i don't have a way to get a copro... Someday... you can get #3 only by practice. solder some random wires together, solder some random wires to some random boards, desolder some random parts, etc. or if you know someone, then there ya go i dunno why you'd really need to do soldering work onto your 386 board. most 386 boards i've seen have the socket to accept an oscillator for the coprocessor. maybe your board runs the coprocessor at the same speed as the processor?
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Post by Tom Maneiro on Sept 20, 2006 15:47:05 GMT -5
My AcerMate mobo has the oscilator soldered, but i had an Epson board that has a socket for the oscilator. Unfortunately, i broke that socket!
Here, in the country of cheapo thingies, almost everything is soldered. Why waste 10 cents on a socket? One millon boards, $100000 saved! Result: PROFFFIT!
Anyway, what's the name for the 386 oscilator form factor?
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oompa loompa
I AM THE GOVERNATOR
"Git 'Er Dun!"
Posts: 1,301
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Post by oompa loompa on Sept 20, 2006 16:39:08 GMT -5
most crystal oscillators for 386 boards are 14-pin dips eg: fits in here: as you can see, the socket for the coprocessor's oscillator is just below the coprocessor (just the pga socket shown) on the right side. tom, are you sure that if you desolder your oscillator, that everything else on the board will still work? like, i hope the oscillator's speed isn't 14.31818mhz
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