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386 PC Suggestions

Z

Zippy Zapp

Experienced Member
Joined
Dec 13, 2014
Messages
259
Location
USA:CA
Greetings All,

I recently found a 386 Baby AT board and thought it would be fun to build a PC around it as I didn't experience 386 DOS days as I was an Amiga user until a 486 in 1994.

So I am looking for comments and suggestions and help along the way to make this thing work.

The motherboard I have is a Lucky Star 386SXA 5.0. If you look at the picture in the link there, the one I have is closer to the 2nd picture. Although I can't find any documentation on this rev of the board, there is some for the 4.0 rev. In a nut shell it is an AMD 386SX-40 with an ALI M1217 chipset. Given the dates on the chips (late 1994) this is a later model 386 well within the 486 era. Probably for basic computing and cheaper PCs I am guessing.

It has (4) 30-pin SIMM slots and I am not sure but I assume you need all 4 populated with equal SIMMs? I have 2 sets of (4) 4MB SIMMs but they are parity and maybe this board doesn't like it because no matter what I do I only get 3 short beeps at power on ( AMI BIOS = first 64k RAM error?). I ordered another set of non-parity just in case that is the problem but I am not 100% sure on this. I suppose it could be the size or underlying chip configuration?

Hopefully I can get it to POST.

Once I do here is the components I have. Its a hodge podge mix and I don't even really know what was considered decent in this era.

+ Generic 16-bit VGA card with 256k (Has slots for 2 more DRAMS for 512k). It is based on the Paradise chip (I have confirmed it functions)
+ A 16-bit Trident based VGA with 1MB video ram. (Have not actually tested this one yet)
+ DTE2280E Mulit-IO that has the usual Floppy, EIDE, Parallel, Serial and Gameport.

I have a lot of ISA sound cards from SB16 Pro 2, SB16, AWE32, etc. I also have a generic Yamaha boards, Pro Audio Spectrum, Ensoniq, Adlib clones, etc. So I am covered there.
I have a new AT PSU that I bought back about 5 years ago to use with another AT style board I found at a local thrift store. So I know the PSU works and is decent enough to use.

I have no case for this tiny board yet. I am on the look out for a small tower case that could house this but the prices on eBay are absurd. I can't justify $100-$200 just for a case. If all else fails I can always use one of the many ATX cases I have with a custom IO shield to handle the keyboard and Serial/Parallel ports. I have some 3d printable designs that do work and if you just print the first few layers they make excellent templates for creating metal shields with blank IO shields.

So first the RAM issues. Is this a common problem? Do I need to keep trying random SIMMs or does anyone have any specifics that might help?

Use case on this is probably earlier DOS games, utilities and possibly Terminal type stuff but mainly just to have fun.

Thanks!
 
Just to add a couple things I missed. I removed the barrel battery and amazingly it did not leak even a little. So got lucky on that one. It has an EXT BATT connector so a 3AA holder should do the trick.

For storage I have plenty of IDE drives but more then likely will use a CF card.

I want to install a network card too so I have either an old Linksys 10BaseT, or a 3Com Etherlink.

The first thing to do is get the RAM issues sorted. Though it is interesting if I take the RAM out I would expect that the BIOS would beep about missing RAM. This does nothing. Maybe this board has some faults on it, I don't know. I haven't found my keyboard adapter yet so I havent plugged in a keyboard yet.

Also a correction to the OP it is not a Paradise VGA it is a RealTek/Quadtel RTG3105iE.
I do have a separate Paradise based card but it is an 8-bit card and I would rather use that in my Tandy.
 
Last edited:
The 386SX has a 16-bit bus, so you only need two 30-pin SIMMs to operate. Using parity SIMMs should not cause an issue unless the RAM itself is faulty.
 
Plasma said:
The 386SX has a 16-bit bus, so you only need two 30-pin SIMMs to operate. Using parity SIMMs should not cause an issue unless the RAM itself is faulty.
Click to expand...
Thank you. That is what I thought too. Perhaps something else is dodgy on this board. I will keep trying other modules. I have checked the SIMM sockets and they are clean as I did clean them and no cracked solder joints or anything that I can tell with a magnifier.

I guess I need to dig out an old Mac Classic II as that is the only other board I have that takes 30-pin SIMMs.
 
I have tried many different SIMM modules now and this thing still refuses to get past the beep code for bad RAM. If I take the RAM out there is no beep codes but the same post codes on the analyzer.
What I have tried:
Keyboard connected
Battery Connected
VGA Card connected
Re-flowed all the connections to the SIMM sockets (A couple solder joints looked suspect). Used deoxit, scrubbed them with IPA, etc. They don't seem corroded or damaged. Cleaned all the pins on the SIMMs but these are all known working. (1MB modules and 4MB modules were tried. Both parity and non-parity).
Removed the jumper wire that permanently enables parity check and installed a pin header and a jumper shunt. It probably was not necessary but just in case.
Under-clocked the CPU
Programmed a new 27C512 EEPROM with the BIOS image found on theretroweb. I compared it with the one I read on the boards BIOS and they do differ slightly.

No matter what I try I get the failed RAM beep code.

Any other suggestions? This board looks clean but I will keep digging. I will have some spare SIMM sockets soon (Dual and single) because they are good to have on hand anyway with old Macs around that have plastic clip SIMM sockets.
 
Perhaps I missed something but in your OP what link are you referencing for the pictures?
 
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