This is a Turbo XT motherboard, the CPU is the Siemens 8088, not the ceramic Mitsubishi 8288 bus controller. Bank 0 and 1 each contain 9 256kb chips, so each 256kB with parity. That means 512kB. There are 4 more chips to the left of it, which have 64kb chips (and two little 16kb more for parity), so 32kB extra - total 544kB. To upgrade to 640kB, you'd replace the four big ones with 256kb chips and the little ones with 64kb.

As for what it's worth, that depends greatly on whether you could test it or not, and on where you are located/how uncommon a board like this is.

Trading of items is not allowed in this forum and questions about the value of items should not be allowed either.
Each one decides on his own.

Sorry guys Im not looking to sell here i will promptly withdraw my question, moderators please delete this post if I have asked in error

Hoping wrote on 2022-05-31, 09:28:

Trading of items is not allowed in this forum and questions about the value of items should not be allowed either.
Each one decides on his own.

Give me a break. Asking what an item is worth should be banned? Don't read the post then. There's nothing wrong with someone trying to become more informed. The post didn't mention anything about making a sale here. Let the moderators be the moderators.

Meatball wrote on 2022-05-31, 14:04:

Hoping wrote on 2022-05-31, 09:28:

Trading of items is not allowed in this forum and questions about the value of items should not be allowed either.
Each one decides on his own.

Give me a break. Asking what an item is worth should be banned? Don't read the post then. There's nothing wrong with someone trying to become more informed. The post didn't mention anything about making a sale here. Let the moderators be the moderators.

Ok, that's your point of view and the other one is mine, you have your reasons to think that and I have mine, like you said, if you don't like it don't read it.
Sorry if I ofended you somehow, but I think I didn't because I didn't mention you.
Live in peace, and the other member already informed the OP.

GabrielKnight123 wrote on 2022-05-31, 08:56:

I dont know how much ram it has because I havnt powered it up yet but the manual says a minimum of 256kb and up to 640kb and Is the CPU the one near the empty socket near the power input as its ceramic with "M5L8288S Japan 721102", the board has printed: "10MHz turbo board" and "dtk PIM-TBIO-Z Rev-7"

Luckily there was no battery leakage because it doesnt have a battery but if this board works what would it be worth to sell being an 8088?

Disregarding any debate about whether or not it's allowed to do price checks here (and disregarding the single spam/mild flamabait as well), I reckon you could ask on the vintagecomputer forums (or Vintage Computer Federation they are called nowdays iirc?). They are somewhat more specialized with pre-286 stuff including anything that isn't a PC and they also have a trade subforum where trading is also allowed.

Personally I wouldn't know what your board is worth since 8088 boards isn't exactly my territory 😋

GabrielKnight123 wrote on 2022-05-31, 08:56:

I dont know how much ram it has because I havnt powered it up yet but the manual says a minimum of 256kb and up to 640kb and Is the CPU the one near the empty socket near the power input as its ceramic with "M5L8288S Japan 721102", the board has printed: "10MHz turbo board" and "dtk PIM-TBIO-Z Rev-7"

Luckily there was no battery leakage because it doesnt have a battery but if this board works what would it be worth to sell being an 8088?

If it were mine, I would throw it up on Ebay with a starting bid of $80.88 to be silly, but completely your call. Nice looking board. If you want to discuss the value definitely fodder for VCFED.org. They cover everything from mainframes to late 90s Pentium systems. If you live in the U.S., VCFED has multiple in-person trade meets across the country and throughout the year that are truly fantastic where VCF forum members (and beyond) buy, sell, trade, conduct presentations and everything in between relating to vintage computer hardware. They also have a computer museum in New Jersey. Worth your time. Nothing like meeting folks face to face and trading stories and maybe a beer or meal afterwards.

Definitely try to test it, if it's confirmed working that will allow you to increase the asking price. You just need an XT/AT power supply and a card that can work on an XT-class machine (many old VGA cards can do it despite having a 16-bit connector).

Regarding the board itself, it's just an XT clone board made by DTK, so it should fit any XT clone case that doesn't use a proprietary form factor for the board, which is very useful for anyone that has an empty case and is looking for a new board or wants to replace a broken one. So from the point of view of practical use it's nice for someone interested in XT class machines.

I don't think it has a lot of value as a collectable, that seems mostly reserved to actual IBM boards or some specific OEMs (though maybe there's DTK die hard fans out there, you never know) and usually these boards are all pretty similar in performance, so it's not like it would be used to upgrade anything for someone who already has a working board.

I've always worked on and owned 486 boards and in a way still true to this day as this board is a friends that I'll sell on eBay or Facebook or a forum so thank you for the suggestions where to sell it, my friend is somewhere around 70 and still smoking I should put some of the money I raise for a hypnotherapy appointment as the poor bloke can't quit with patches or champix pills