On the other hand, the jumper designations doesn't match and there are no jumpers near the 287 socket either ..

You can have total of 8 SIP memory modules there. They are like SIMMs, just with pins. I think, you can even solder pins on SIMM module and it works.

GigAHerZ wrote on 2020-02-26, 12:08:

You can have total of 8 SIP memory modules there. They are like SIMMs, just with pins. I think, you can even solder pins on SIMM module and it works.

But would there be room for actually putting a module in each of the two adjacent rows? I mean, with the size of the memory chips, I wouldn't think they could sit there?

Each SIPP socket has pins labelled 1 through 30. Clearly it's not for DIPs, because 30 is not divisible by 8 or 9 (the number of legs per side on memory ICs typically accepted by 286 systems). Although it's tight, there should be just barely enough room to squeeze the SIPPs in there.

Well, only one way to find out 😀 after sorting out that Varta plague, that is ..

Bringing this back to life.

How did you go with the RAM?

I just bought a 386 system that appears to have same motherboard. Do you know what model is it? Is the manual you found correct? Link?

I want to expans the ram, currently has 4x1mb so will try to source some SIPP modules.

GigAHerZ wrote on 2020-02-26, 12:08:

You can have total of 8 SIP memory modules there. They are like SIMMs, just with pins. I think, you can even solder pins on SIMM module and it works.

An easier way to use SIMMs is to get some SIMM slots. The pins (normally soldered to the board) should fit the SIPP slots.

PS: Just always make sure that the orientation is correct. SIPP modules can easily be inserted the wrong way around.

I just googled but cant seem to find any EDO RAM SIMM slots only, got any links ?

GigAHerZ wrote on 2020-02-26, 12:08:

You can have total of 8 SIP memory modules there. They are like SIMMs, just with pins. I think, you can even solder pins on SIMM module and it works.

I did that, it really works. The SIMM type should be the normal one (FP, Fast Page).

This method is fine if you have known good RAM and if the RAM is meant to stay permanently installed, anyway.

It's fine for 4x 1 MB SIMMs, for example. That's the limit of many 286 chipsets.

As pins, resistor legs can be used, for example. It's the kitchen method, essentially, if no special pin strips are in the house.

Real pin strips are better to solder, though. They won't bend as easily, either.

Installing SIMM sockets is even better. But there's the space issue, sometimes.

Some 286 motherboards with SIPP "slots" are very crowded and won't allow normal SIMM sockets to fit next to each others. 🙁

thanks but I am not great at soldering and dont want to damage a precious rare AND working 386 system, I just want to add more RAM without breaking the bank. SIPP modules are extremely rare and cost more than the whole system cost me which was already a bit.

Omarkoman wrote on 2024-04-28, 21:31:

thanks but I am not great at soldering and dont want to damage a precious rare AND working 386 system, I just want to add more RAM without breaking the bank. SIPP modules are extremely rare and cost more than the whole system cost me which was already a bit.

You don't have to. The SIPPs aren't worth their price in my opinion, so it's kind of good they're rare. 😉

In practice, SIPP sockets are really just a cheap substitute for proper SIMM sockets.

Real SIPPs also came in slow (120ns and up) and low-capacity versions. The 256KB type was most popular, I think.

A modern SIMM module (80ns or less) with attached pins is much more practical, I think.
Especially on a 386 motherboard.

Maybe you can find modern SIPPs (replica etc) on eBay or in other places.
Sometimes people sell such things they've made on their own.

Just keep in mind though: A 386 needs 4x same type for a bank, a 286 2x same type.

It's because of bitness. SIPPs/SIMMs are 8-Bit wide, the 386 has 32-Bit data width, the 286 has 16-Bit data width.

Also, it seems that your board has numbers on the SIPP sockets. 1 and 30. This may help to find out correction orientation of RAM modules. It's just a guess, though.

Good luck! 🙂👍

thanks, found these :

https://www.ebay.com.au/itm/175843995849

overkill for a 386 to have 16MB but its the best value price vs spec .... as single 1MB SIPPs appear to cost as this whole lot. Expensive though as by the time I add postage to Australia and import duty it more than doubles the price so around $110 USD. I guess its not much money in grand scheme of things.

and apologies but I dont understand, how can I use EDO SIMM memory to install in the SIPP socket ? the adapters wont work as there is not enough space to put 4 from what I saw plus they are expensive too. So how do I "attach" pins/legs to SIMM slot if I dont solder? Thanks.

Omarkoman wrote on 2024-04-28, 21:59:

thanks, found these : […]
Show full quote

thanks, found these :

https://www.ebay.com.au/itm/175843995849

overkill for a 386 to have 16MB but its the best value price vs spec .... as single 1MB SIPPs appear to cost as this whole lot. Expensive though as by the time I add postage to Australia and import duty it more than doubles the price so around $110 USD. I guess its not much money in grand scheme of things.

and apologies but I dont understand, how can I use EDO SIMM memory to install in the SIPP socket ? the adapters wont work as there is not enough space to put 4 from what I saw plus they are expensive too. So how do I "attach" pins/legs to SIMM slot if I dont solder? Thanks.

Better make sure that the chipset supports that memory size in that package. I have a set of those SIPPs as well and they don't work for me as none of the chipsets on boards with SIPP slots I have support this memory config. I am going to de-solder the pins of those so I can use them as SIMMs in a 486. 😀

Omarkoman wrote on 2024-04-28, 21:31:

thanks but I am not great at soldering and dont want to damage a precious rare AND working 386 system, I just want to add more RAM without breaking the bank. SIPP modules are extremely rare and cost more than the whole system cost me which was already a bit.

As I mentioned in a previous comment, just get some SIMM slots as an adaptor, they fit into SIPP slots, that way you can use standard 30 pin SIMM modules.

https://www.peconnectors.com/sockets-pga-cpu- … memory/hws5040/

You might have to clip/trim off the stand-offs (left/right) side and hopefully there is enough clearance on the board. This way you don't need to solder/de-solder anything.

thanks but I dont see how I can fit 4 of them as the space does not appear to be there.

that shop doesnt send items to Australia, I saw them when I googled but unfortunately a no go. And cant find anything locally. Either way, it will be expensive and I am better off buying ready to go SIPP modules.

Whether the motherboard supports it or not, I am not sure, thats why I asked the original poster here to share the manual link. The board in the picture in the first post of this thread is the same one the machine I bought has. So if anyone can see and tell me if it supports 4MB modules, that would be greatly appreciated. Thank you.

Omarkoman wrote on 2024-04-29, 00:21:

that shop doesnt send items to Australia, I saw them when I googled but unfortunately a no go. And cant find anything locally. Either way, it will be expensive and I am better off buying ready to go SIPP modules.

Ah, that was just an example of what kind of slots I was referring to (the first thing Google came back with). You don't HAVE to buy those from THAT shop, you can buy 'm anywhere. 😀

There are also double-slots variants available:

https://www.peconnectors.com/sockets-pga-cpu- … memory/hws9594/

Again, you don't HAVE to buy from that shop, just an example 😀

Finding actual SIPPs is probably best but they are 1) expensive and 2) typically it's slow ass memory, like 120ns or something.

Thanks and yes of course there are options but locally i can find ones that are MORE for four of them than buying the ones i linked in the ebay link above. They are also 60ns chips.

Just need to find out now if the motherboard can take 4mb modules.

bump ....

hoping someone here can identify the motherboard in the first post as its exactly same one I have and I am looking for manual how to set switches for installing higher CPU (mine comes with 386 SX 25 and I want to put in a 386 DX-40 (AMD))

thank you !

PS: I received the 4 x $M SIPP memory I linked up, its a beauty !

It looks like this one: https://theretroweb.com/motherboards/s/armas-mst-1267-a

But there's no manual uploaded on TRW site, so use the picture from the first post in the thread (jumper settings at the bottom):