Re: Looking for AMD 287 diskette
Posted on 2020-02-27, 13:00
Yes. I was mostly interested in fractal generator. It takes really long time on a 286-16 with 287. I'll use it to do some benchmarks.
Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 16:34
Hello, I received today a bunch of cpus with bent pins, the cpu on the subject had this pin that went of when just touched, it is the one on the keyed side. In this page is identified as D20: http://ps-2.kev009.com/eprmhtml/eprmx/h12203.htm In this picture is the A1: https://ptgmedia.pearsoncmg.com/ …
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 17:08
As you can see in the second picture there are 4 rows each side and first one there are 3 rows on each side so they are not the same pin. It is D20 in both pictures. I think that pin is in use. D0-D31 are the data pins.
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 17:09
It's D20 and the pin is required, as it's a signal of the data bus. It's not PLUG, as the 2nd link shows socket 2 with the outer row of pins only used by the Pentium Overdrive.
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 17:17
ops, I didn't notice it was socket 2... That's sad, what can I do now? Here is a picture of the cpu: https://imgur.com/a/PjsB8lF
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 17:21
It miiiight be possible to solder the pin back to the stubs I see in the hole and then covering things in epoxy to get mechanical strength necessary. That pin is essential to operation and it won't be possible to run the CPU without it.
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 17:30
Try to get a fitting PGA socket to put the CPU into. This way, you can solder a wire from the pad of the broken pin to the pin of the socket and avoid any stress on that repaired connection.
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 17:33
Just out of curiosity. Since the CPU starts real mode would it at least attempt to boot somehow? Or would it just hang due to using 32bit bursts during the first cache line fill?
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 17:35
Tomorrow I will give a try and report back... Tido, just in case, you will be my man 😁 Thank you everyone
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 17:45
mpe wrote on 2020-02-27, 17:33: Just out of curiosity. Since the CPU starts real mode would it at least attempt to boot somehow? During POST, switching to protected mode is already tested, so it will most likely not even show anything on screen at all.
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 18:14
Every time cache miss occurs CPU will initiate cache line fill. On 486 cache it's 16 bytes - 4 bytes per 4 transactions. So all data lines are required to perform cache fill.
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 18:30
Just out of curiosity. Since the CPU starts real mode would it at least attempt to boot somehow? Or would it just hang due to using 32bit bursts during the first cache line fill? It will attempt to boot but will read corrupted data on the very first code fetch. The 486 expects data read from …
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 18:50
Actually both cache and prefetcher use all 32 data lines. So with one data line missing it should not work.
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 19:50
Similar. My DX2-50 is missing a VCC pin (whatever that means) it's unlabeled, but it's a red pin, R14. Will mine work?
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 20:33
Great was tempted to clip the pin on my CPU just for the sake of science. Similar. My DX2-50 is missing a VCC pin (whatever that means) it's unlabeled, but it's a red pin, R14. Will mine work? VCC is +5V power supply that is repeated on the chip couple of times to improve current delivery. So there …
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 21:37
Great was tempted to clip the pin on my CPU just for the sake of science. Similar. My DX2-50 is missing a VCC pin (whatever that means) it's unlabeled, but it's a red pin, R14. Will mine work? VCC is +5V power supply that is repeated on the chip couple of times to improve current delivery. So there …
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 22:33
Got a 5x86 that is missing the same D20 pin and a 486 that has no W/R# pin. I don't expect them to work this way, but I'm thinking of using them for an experiment. Do you think it would be possible to remove the die cap (seems to be soldered) and maybe attach a very thin wire to the leadframe (after …
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-27, 23:42
How does this type of damage occur? Is it from trying to pry them out of non-ZIF sockets?
Re: AMD stopped producing Radeon VII
Posted on 2020-02-28, 12:21
ynari wrote on 2020-02-28, 11:28: The Radeon VII is a fairly useless GPU unless you need to do compute, in which case it's a bargain. This is the wrongest thing I've read all day.
Re: Amd Am486 DX-40 with missing pin
Posted on 2020-02-28, 12:30
Got a 5x86 that is missing the same D20 pin and a 486 that has no W/R# pin. I don't expect them to work this way, but I'm thinking of using them for an experiment. Do you think it would be possible to remove the die cap (seems to be soldered) and maybe attach a very thin wire to the leadframe ( …
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