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Jumpers settings needed for CH-880C (486) and V3486EF (386/486)

A

Arkady

Experienced Member
Joined
Jun 14, 2011
Messages
60
Location
Reunion Island (FR)
Hello,

I've been searching for a long time for the jumpers settings of these two motherboards:

CHICONY CH-880C Rev. 1.0 (socket 3 motherboard)
ALLIED (?) V3486EF Rev.1.42 ( 386 socket and 486 socket)

The two boards came with no CPU. I installed the Am386DX onto the V3486EF , but the motherboard didn't boot. Nothing, nada, rien.
Any help would be greatly appreciated... ;)
Thank you.

CHICONY CH-880C

CH_880C_REV1.jpg


V3486EF Rev.1.42

V3486EF_REV142.jpg
 
diodenmann said:
Isn't the 386 installed in the wrong direction? Pin 1 of the socket should match the triangular mark I think...
Click to expand...

No, the marking is horrible on this CPU:(: the triangular mark is for the orientation of the CPU onto the small PCB BEFORE it was soldered.
Note the "A 1" mark at the opposite side of the triangular mark. That's the right direction.
 
Ok, but isn't it still the wrong direction? If the "A 1" mark on the processor board indicates Pin 1, this corner has to face to the upper right corner of the CPU socket (on the side where the 1---14 is written on the mainboard) ?
 
diodenmann said:
Ok, but isn't it still the wrong direction? If the "A 1" mark on the processor board indicates Pin 1, this corner has to face to the upper right corner of the CPU socket (on the side where the 1---14 is written on the mainboard) ?
Click to expand...

Definitively no: look at the picture below, without the 386 CPU.

386socketEFAR.jpg


But i really need to thank you a lot.
I "know you" because you sell outstanding first quality vintage computer items on eBay. Once or twice, i managed to buy from you, but... auction prices often go too high for me :huh:
So, i was always asking to myself, several times : " and if he was right..." and then, i noticed the REAL problem of this motherboard. The EFAR EC798 chipset was damaged (poor storage before i got it?) and it had an unsoldered pin (see red arrow on the picture below).
I straightened a bit three other pins, but i decided to solder the last one as-is, even if it was really bent: i feared to break it.

And then, BINGO! The motherboard booted but stopped at the memory test (no display, but i read the BIOS codes from the diagnostic ISA card). I disassembled the 386 CPU, put a 486DX33 instead and then it booted to MS-DOS.
The fix doesn't look nice (remaining solder onto the pin), but i can't do better than that.

The speed is locked at 25MHZ, so still really need informations about the jumpers settings...
Thank you for your help.

Damaged EFAR.jpg
 
3pcedev said:
http://www.uncreativelabs.de/th99/

Not the easiest to search but I bet they are in there somewhere.....
Click to expand...

Thank you, but i've got "Total Hardware 99" on my hard drive.
I searched among the 386 and 486 motherboards, looking at EACH picture. Nothing, peanuts, nada, rien. :(
Then, i searched the "word" 3486 in each description. Nothing, peanuts, nada, rien. :(:(
Tryied archive.org and my friend GOOGLE. Nothing, peanuts, nada, rien. :(:(:(

Last, i came here and asked for "Santa Claus"! :D

Have a good day.
 
Hello,

Ok, i guessed the jumpers setting for the CPU voltage with the MIC29152 datasheet and the resistors value from the motherboard (Chicony CH-880C). I have got:

P1,P2,P3 : 1-2 on (2-3 off)
P4 : 1-2 on -> 3.1v
P4 : 3-4 on -> 3,3v
P4 : 5-6 on -> 3,45v
P4 : 7-8 on -> 3,60v
P4 : 9-10 on -> 4,00v​

P1,P2,P3 : 2-3 on (1-2 off) : 5v (p4 setting doesn't matter).

The CPU clock settings are written onto the motherboard.

So these are my questions:
- what is the purpose of the CPU type settings (AMD/INTEL/CYRIX, SX/DX/DX2/DX4)?
- Is there a risk of killing the motherboard or the CPU if i plug a CPU with its correct voltage and clock settings, but with a wrong CPU type setting (ex: INTEL SX CPU setting, with an INTEL/AMD DX2 plugged)

Happy new year 2016 for all, health and happiness (and tons of old rare vintage computer stuff!!! :D)
 
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