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Everex Step 386is troubleshooting

F

Formulator

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A quite clean system, but sadly will not post. Has LED display and speaker toggle. RAM tested OK in other system, (except for one DIMM from empty socket).

I suspect issue is with the InSTEP 387 upgrade board. Since this was originally a 286 board, I want to verify which type of alternate CPU to test with.

Given complexity of upgrade board, I would suspect to test with 68-pin 286, but wanted to know if a 386 would drop in, since BIOS may support it.


IMG_1881.jpgIMG_1874.jpgIMG_1873.jpg
 
The review of the system I found says that the base design is a 286-16. Double check the crystal. But that would be where I would start.

I doubt a 386SX would work in the motherboard socket. Intel failed in their goal of making the 386SX a drop in replacement for the 286, some small changes needed to be made to the motherboard or hidden on an adapter card.
 
That's pretty neat. I didn't know Everex sold a 286 system with a 386sx upgrade module. I suspect that the upgrade card is fine. The easiest way to confirm if the board is dead is with a 286 16MHz CPU. The PGA version of this chip is pretty rare, but the PLCC version is plentiful. You should be able to get a PLCC socket for under $1 that will plug into the PGA socket and let you use a PLCC 286-16. If the upgrade module is dead, you could consider an aftermarket 386/486 upgrade like the "Make it 486".

More than likely your motherboard just has a bad RAM chip, capacitor or solder joint.
 
Anonymous Coward said:
That's pretty neat. I didn't know Everex sold a 286 system with a 386sx upgrade module. I suspect that the upgrade card is fine. The easiest way to confirm if the board is dead is with a 286 16MHz CPU. The PGA version of this chip is pretty rare, but the PLCC version is plentiful. You should be able to get a PLCC socket for under $1 that will plug into the PGA socket and let you use a PLCC 286-16. If the upgrade module is dead, you could consider an aftermarket 386/486 upgrade like the "Make it 486".

More than likely your motherboard just has a bad RAM chip, capacitor or solder joint.
Click to expand...

That sounds sensible, will test with 286-16. I do notice that the InSTEP module required socket extensions to clear it above the other IC's below, so it may be worth testing with replacements. Also, upon closer inspection the co-processor socket extension seems to be slightly higher than the CPU socket; makes me wonder if not all of the pins are making a good connection with the main CPU socket. If this is the case I suspect the machined holes in the socket extension may be to large and the conical part of the pins need to make better contact, in which case I will have to test with a lower-profile 40-pin socket. I guess we will see.
 
That is such a bizarre CPU upgrade path. I wonder if at some point in an effort to get rid of unsold 286 boards they instead built that adapter so then could cram them in 386 branded machines, then continued from there once stock ran out and they had a proper 386 board and system shipping?
Also it intrigues me if you could upgrade the upgrade further, by dropping a 386SL to 486 upgrade.

edited: Actually, pull the 387 out and see if it posts then? It is unlikely but I have seen a bad co-pro hang up a system before.
 
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