Could you please post a picture of the card and ram chips? I haven't seen a 8900B with 256KB VRAM and 8 empty sockets before. Did you add with 256KB chips? That's probably too big for 8900B to handle.

Sorry, I guess I didn't express myself clearly. The board has 8 chip sockets. I removed the original two and inserted 8 chips that I took from a 286 motherboard.

Half-Saint wrote:

Sorry, I guess I didn't express myself clearly. The board has 8 chip sockets. I removed the original two and inserted 8 chips that I took from a 286 motherboard.

Do you have the model number of the ram chips?

I'm not sure what the problem is, but just to be sure the basics are there:

For having 1MB with 8 pieces of "256K" chips, you need to use 44256 chips. If you use 41256 (or 4464), then the total will be only 256KB.

44256

41256

4464

tayyare wrote:

I'm not sure what the problem is, but just to be sure the basics are there:

For having 1MB with 8 pieces of "256K" chips, you need to use 44256 chips. If you use 41256 (or 4464), then the total will be only 256KB.

These chips have incompatible pinouts. I would be surprised if they can be used on a 8900 without setting jumpers.

lazibayer wrote:

These chips have incompatible pinouts. I would be surprised if they can be used on a 8900 without setting jumpers.

No, it is physically possible to insert 41256 and 4464 chips into 44256 sockets. How does a 8900 will behave when you do, I don't know, never tried. I just wanted him to be sure. I've seen 286 boards accepting both 41256 and 44256 DIP RAMs as main memory (he said he removed the chips from a 286 mobo)

I have a Trident 8900D with 1MB memory in these chips, shall I take a picture of it for you?

The chips that were oiginally installed are 2x Goldstar GM 71C4256A-80 and I used 8x TMS44C256-80N.

tayyare wrote:

No, it is physically possible to insert 41256 and 4464 chips into 44256 sockets. How does a 8900 will behave when you do, I don't know, never tried. I just wanted him to be sure. I've seen 286 boards accepting both 41256 and 44256 DIP RAMs as main memory (he said he removed the chips from a 286 mobo)

Most 286 boards with the ability of taking different ram chips have jumpers to set for the type of memory being used. That's why I ask if the OP can provide photos of his card so we can see if there are similar jumpers to take care of that.

You don't really have to quote everything everyone before you said, makes the post harder to read and the thread longer than necessary. Read my post above yours for clarification regarding which chips I used.

Half-Saint wrote:

You don't really have to quote everything everyone before you said, makes the post harder to read and the thread longer than necessary. Read my post above yours for clarification regarding which chips I used.

OK I shortened my post.
Yes I read your post and no longer ask for chip models. They are in theory compatible. In fact, I was asking if there are any jumpers regarding RAM size selection on your card in my post above yours.

There are jumpers but I have no idea what they do. Here's what my card looks like only different colour, the rest is identical down to jumper config:
http://www.yjfy.com/images/oldhard/video/TMI_4820.jpg

Notice that the card in the picture has 1MB installed? The jumpers on my card are set the same way.

Half-Saint wrote:

There are jumpers but I have no idea what they do. Here's what my card looks like only different colour, the rest is identical down to jumper config:
http://www.yjfy.com/images/oldhard/video/TMI_4820.jpg

Notice that the card in the picture has 1MB installed? The jumpers on my card are set the same way.

I found some links with Trident Cards with similar (though not same) layout:

http://museum.ttrk.ee/th99/v/A-B/54450.htm
http://museum.ttrk.ee/th99/v/C-D/54028.htm
http://museum.ttrk.ee/th99/v/U-Z/50459.htm
http://museum.ttrk.ee/th99/v/U-Z/50749.htm
http://museum.ttrk.ee/th99/v/U-Z/50681.htm

Unfortunately, the jumpers are not the same, and no info about RAM size/jumper relation. We can maybe just say that jumpers on your card also are not related to RAM size. To say the truth, this is my experience with one Oak and two Trident cards. I upgraded them from 256/512KB to 512KB/1MB by myself using 44256 chips, and they just started seeing the total installed memory automatically at first boot (all three of them actually reporting total installed video RAM on boot screen).

Did not find any info on 8900B, but there are other 8900 cards in th99:
http://museum.ttrk.ee/th99/v/U-Z/54493.htm
http://museum.ttrk.ee/th99/v/U-Z/51392.htm
http://museum.ttrk.ee/th99/v/U-Z/50813.htm
http://museum.ttrk.ee/th99/v/U-Z/50681.htm
http://museum.ttrk.ee/th99/v/U-Z/50105.htm

Maybe that will give you clue as to what jumpers to move. Some do relate to memory size.

Half-Saint wrote:

There are jumpers but I have no idea what they do. Here's what my card looks like only different colour, the rest is identical down to jumper config:
http://www.yjfy.com/images/oldhard/video/TMI_4820.jpg

Notice that the card in the picture has 1MB installed? The jumpers on my card are set the same way.

I just realized something from your picture. I was thinking "what the heck are those 5th RAM sockets?" in each memory bank, and realized that they are actually some kind of jumper sets (designated JP1 and 2 - never seen anything like it before), and the lower bank has a terminator or something on it. Probably you are already aware, but I just wanted to remind, because they might definitely be related to memory size configuration.

OMG my post almost exactly duplicates your, tayyare oO I swear it was not there!

tayyare wrote:

I just realized something from your picture. I was thinking "what the heck are those 5th RAM sockets?" in each memory bank, and realized that they are actually some kind of jumper sets (designated JP1 and 2 - never seen anything like it before), and the lower bank has a terminator or something on it. Probably you are already aware, but I just wanted to remind, because they might definitely be related to memory size configuration.

Yes the "sockets" are actually jumpers, and yes, they are related to size selection.

http://stason.org/TULARC/pc/graphics-cards/U- … ml#.VNJQNrui7mE

A good photo is better than a thousand words.

RacoonRider wrote:

OMG my post almost exactly duplicates your, tayyare oO I swear it was not there!

No problem, understood the situation perfectly. It happened to me once or twice. 🤣

lazibayer wrote:

Yes the "sockets" are actually jumpers, and yes, they are related to size selection.

http://stason.org/TULARC/pc/graphics-cards/U- … ml#.VNJQNrui7mE

A good photo is better than a thousand words.

Oh wow! That's great! Can't wait to try this out tomorrow 😀