I'm posting here to remind myself to come back later. I have this board in my 486. Identical version.

Parni wrote on 2020-06-29, 18:09:

Thanks! Now i'm just wondering what E/EEPROM programmer to buy 😀 any tips?

Also why do you recommend 32-pin in favour to the original 28-pin?

What come to the BIOS chips, could you also advice what are suitable 28 and 32-pin chips?

Just use any Pentium motherboard and Uniflash. It's easy and free.
They usually have a 32-pin EEPROM, so that's why I suggested you that.

The difference of pins signifies the number of address pins a given EPROM chip has. You need 32-pin chips to write ROMs larger than 64KB. Check this and also this.

You will have to use 29Fxxxx EEPROM chips (electrically eraseable) if you plan to flash with a Pentium motherboard.

You could also get a TL-866 from Aliexpress or eBay if you want. UV chips require exposure to ultraviolet light before they can be written with special hardware (such as TL-866).

Your jumpers (in the picture on the first page) seem to match the ones I have configured for a 486DX2-66.

Can we please see a full picture of your board as you're testing it? Is it on anything or in anything?

How is your CPU oriented?

How are the leads of the chipset? Are any bent and making contact with other leads?

I agree that the BIOS is a good place to go. I can pull the one that came on my board, if you'd like that.

computerguy08 wrote on 2020-06-29, 19:11:

Just use any Pentium motherboard and Uniflash. It's easy and free. They usually have a 32-pin EEPROM, so that's why I suggested […]
Show full quote

Parni wrote on 2020-06-29, 18:09:

Thanks! Now i'm just wondering what E/EEPROM programmer to buy 😀 any tips?

Also why do you recommend 32-pin in favour to the original 28-pin?

What come to the BIOS chips, could you also advice what are suitable 28 and 32-pin chips?

Just use any Pentium motherboard and Uniflash. It's easy and free.
They usually have a 32-pin EEPROM, so that's why I suggested you that.

The difference of pins signifies the number of address pins a given EPROM chip has. You need 32-pin chips to write ROMs larger than 64KB. Check this and also this.

You will have to use 29Fxxxx EEPROM chips (electrically eraseable) if you plan to flash with a Pentium motherboard.

You could also get a TL-866 from Aliexpress or eBay if you want. UV chips require exposure to ultraviolet light before they can be written with special hardware (such as TL-866).

OK, I will get myself an TL-866 as I might need it also with my other projects. If I will use the 28-pin chips does it matter if I use EPROM or EEPROM modules? Any clue what size would be suitable for typical 486 BIOS?

fitzpatr wrote on 2020-06-29, 21:16:

Your jumpers (in the picture on the first page) seem to match the ones I have configured for a 486DX2-66. […]
Show full quote

Your jumpers (in the picture on the first page) seem to match the ones I have configured for a 486DX2-66.

Can we please see a full picture of your board as you're testing it? Is it on anything or in anything?

How is your CPU oriented?

How are the leads of the chipset? Are any bent and making contact with other leads?

I agree that the BIOS is a good place to go. I can pull the one that came on my board, if you'd like that.

Please find the full picture below, all my other boards works fine in the same place 😀
My CPU is oriented as it should be, the bulky corner accordingly to the socket.
Chipset leads look good, no contact.

I would appreciate VERY much if you could pull me the BIOS, I could flash it to my chip as soon I get the TL-866 programmer. Is it also V5 board that you have?

Btw. What memory are you using? I have noticed Opti895 can be quite exact what memory it accepts, for Instance my Shuttle HOT 419 only accepts single sided parity FPM memory

Parni wrote on 2020-06-30, 18:29:

OK, I will get myself an TL-866 as I might need it also with my other projects. If I will use the 28-pin chips does it matter if I use EPROM or EEPROM modules? Any clue what size would be suitable for typical 486 BIOS?

Most typical 486 boards use 64KB BIOS images, which translates to a 27C512 EPROM. The image I provided you should work properly.

The difference between the two is that (E)EPROMs can be erased electrically, whilst the EPROM has to be erased with UV light (place it under a UV neon for ~20 minutes).
EPROMS have to be erased with UV prior to writing code on them. They have a round window on top of the chip, usually underneath a sticker (to protect it from acccidental erasure).

Okay. I'll try to get the BIOS uploaded in the next couple of days.

Check my signature for my 486 build log. I'll get info on the RAM at the same time. I also have the v5, so the BIOS should be golden for you!

computerguy08 wrote on 2020-06-30, 20:58:

Most typical 486 boards use 64KB BIOS images, which translates to a 27C512 EPROM. The image I provided you should work properly. […]
Show full quote

Parni wrote on 2020-06-30, 18:29:

OK, I will get myself an TL-866 as I might need it also with my other projects. If I will use the 28-pin chips does it matter if I use EPROM or EEPROM modules? Any clue what size would be suitable for typical 486 BIOS?

Most typical 486 boards use 64KB BIOS images, which translates to a 27C512 EPROM. The image I provided you should work properly.

The difference between the two is that (E)EPROMs can be erased electrically, whilst the EPROM has to be erased with UV light (place it under a UV neon for ~20 minutes).
EPROMS have to be erased with UV prior to writing code on them. They have a round window on top of the chip, usually underneath a sticker (to protect it from acccidental erasure).

Ok, thanks for the info. I will need 28-pin chips also for my other motherboards to play around with various BIOS versions and maybe the UV-light erasable isn't that convenient. So would these EEPROM's be suitable for a 486 bios chip? https://www.ebay.com/itm/10PCS-28Pin-EEPROM-I … UMAAOSwnKFeS-jY

fitzpatr wrote on 2020-07-01, 06:08:

Okay. I'll try to get the BIOS uploaded in the next couple of days.

Check my signature for my 486 build log. I'll get info on the RAM at the same time. I also have the v5, so the BIOS should be golden for you!

Ok
Thank you! I appreciate it very much!! I have tried to find this bios everywhere so you are really giving me a great help 😀

Parni wrote on 2020-07-01, 09:41:

Ok, thanks for the info. I will need 28-pin chips also for my other motherboards to play around with various BIOS versions and maybe the UV-light erasable isn't that convenient. So would these EEPROM's be suitable for a 486 bios chip? https://www.ebay.com/itm/10PCS-28Pin-EEPROM-I … UMAAOSwnKFeS-jY

The item you linked is only capable of holding 32KB (too small), but yes, these kinds of Atmel EEPROMs should work very well.

I'll give you some more background on the 32-pin chip situation. I'm generally too lazy to order new 28-pin EEPROMs from eBay and I already have a stash of 32-pin EEPROMs from various Pentium poards.
So what I ended up doing was to concatenate the desired BIOS image with a hex editor (cloning the contents basically) until I got to the size of the BIOS chip I was going to use.
After that, I solder the unused address pins to Vcc (or GND, doesn't matter) and put it in the 28-pin socket of the motherboard with pins 1, 2, 31 and 32 hanging outside the socket.

You can make this treatment to a socket instead and use that between the motherboard and the 32-pin chip. If you take a look at the datasheet, you'll understand why this works.

I have to admit, this is not that easy to make at first glance and it looks janky, but it saved me time and money (i didn't have a TL-866).

computerguy08 wrote on 2020-07-01, 12:26:

The item you linked is only capable of holding 32KB (too small), but yes, these kinds of Atmel EEPROMs should work very well. […]
Show full quote

Parni wrote on 2020-07-01, 09:41:

Ok, thanks for the info. I will need 28-pin chips also for my other motherboards to play around with various BIOS versions and maybe the UV-light erasable isn't that convenient. So would these EEPROM's be suitable for a 486 bios chip? https://www.ebay.com/itm/10PCS-28Pin-EEPROM-I … UMAAOSwnKFeS-jY

The item you linked is only capable of holding 32KB (too small), but yes, these kinds of Atmel EEPROMs should work very well.

I'll give you some more background on the 32-pin chip situation. I'm generally too lazy to order new 28-pin EEPROMs from eBay and I already have a stash of 32-pin EEPROMs from various Pentium poards.
So what I ended up doing was to concatenate the desired BIOS image with a hex editor (cloning the contents basically) until I got to the size of the BIOS chip I was going to use.
After that, I solder the unused address pins to Vcc (or GND, doesn't matter) and put it in the 28-pin socket of the motherboard with pins 1, 2, 31 and 32 hanging outside the socket.

chip1.jpg

You can make this treatment to a socket instead and use that between the motherboard and the 32-pin chip. If you take a look at the datasheet, you'll understand why this works.

I have to admit, this is not that easy to make at first glance and it looks janky, but it saved me time and money (i didn't have a TL-866).

That looks really impressive 😀 However I purchased already an TL-866 and I should have it shortly.
About the AT28C256-15PU EEPROM 28-pin module, you mentioned it is too small (32KB)? The datasheet states it as 256Kb? https://fi.farnell.com/atmel/at28c256-15pu/ic … 8dip/dp/1095782

I'm still looking for suitable 28pin BIOS chips, but quite frankly im strugling how to determine the capacity

Parni wrote on 2020-07-01, 19:09:

That looks really impressive 😀 However I purchased already an TL-866 and I should have it shortly.
About the AT28C256-15PU EEPROM 28-pin module, you mentioned it is too small (32KB)? The datasheet states it as 256Kb? https://fi.farnell.com/atmel/at28c256-15pu/ic … 8dip/dp/1095782

I'm still looking for suitable 28pin BIOS chips, but quite frankly im strugling how to determine the capacity

This is a common mistake, you are looking at 256 kilobits (indicated by the smaller b), not kilobytes. What you are actually looking for is the number of words that can be addressed on the chip.
In this case, you have 32768 addressable words (which translates to roughly 32kilobytes, where 8 bits = 1 byte). To summarize, you need to be looking for EEPROMs with 65536 addressable words (~64KB) at minimum.

I hope I was clear enough 😀

P.S: You can still buy the 28C256 chips if you want, I'm sure they will be useful for other 286 or 386 boards (they just won't work with the QDI 486 you have).

computerguy08 wrote on 2020-07-02, 14:26:

This is a common mistake, you are looking at 256 kilobits (indicated by the smaller b), not kilobytes. What you are actually loo […]
Show full quote

Parni wrote on 2020-07-01, 19:09:

That looks really impressive 😀 However I purchased already an TL-866 and I should have it shortly.
About the AT28C256-15PU EEPROM 28-pin module, you mentioned it is too small (32KB)? The datasheet states it as 256Kb? https://fi.farnell.com/atmel/at28c256-15pu/ic … 8dip/dp/1095782

I'm still looking for suitable 28pin BIOS chips, but quite frankly im strugling how to determine the capacity

This is a common mistake, you are looking at 256 kilobits (indicated by the smaller b), not kilobytes. What you are actually looking for is the number of words that can be addressed on the chip.
In this case, you have 32768 addressable words (which translates to roughly 32kilobytes, where 8 bits = 1 byte). To summarize, you need to be looking for EEPROMs with 65536 addressable words (~64KB) at minimum.
Capture.PNG

I hope I was clear enough 😀

P.S: You can still buy the 28C256 chips if you want, I'm sure they will be useful for other 286 or 386 boards (they just won't work with the QDI 486 you have).

Heh 😀 yes my mistake, you are right. These should be suitable? https://www.ebay.com/itm/10PCS-EEPROM-IC-WINB … 9QAAOSwLpRdXpAi

Parni wrote on 2020-07-02, 18:02:

Heh 😀 yes my mistake, you are right. These should be suitable? https://www.ebay.com/itm/10PCS-EEPROM-IC-WINB … 9QAAOSwLpRdXpAi

Yes, it should be a good choice. Here is a chip support list for the TL-866 (for future reference).

computerguy08 wrote on 2020-07-02, 19:07:

Parni wrote on 2020-07-02, 18:02:

Heh 😀 yes my mistake, you are right. These should be suitable? https://www.ebay.com/itm/10PCS-EEPROM-IC-WINB … 9QAAOSwLpRdXpAi

Yes, it should be a good choice. Here is a chip support list for the TL-866 (for future reference).

Thanks! 😀

Hi Parni,

Here is the BIOS file from mine! It is from a TI TMS27c512 read using a TL866II Plus.

This is my first time using the programmer, so no guarantees. I am seeing the Name and Date of the BIOS in the .bin, though, so I think that it's good.

fitzpatr wrote on 2020-07-05, 03:24:

Hi Parni,

Here is the BIOS file from mine! It is from a TI TMS27c512 read using a TL866II Plus.

This is my first time using the programmer, so no guarantees. I am seeing the Name and Date of the BIOS in the .bin, though, so I think that it's good.

Thank you so much!!! I think it will take 2-3 week for my TL866II to arrive from China, so stay tuned 😀 I will report the situation after I have flashed the BIOS.

Ps. I had a look on your 486 setup 😀 highly impressive 😀 just out if curiosity, what kind of fps do you get in 3dbench?

Here is a picture of the RAM that I'm using.

2x 8MB sticks (1Mx4b x 16 chips)

NN514400AJ-60

I'm back! I got the TL866 Plus from China, however I think there are some issues with it. I'll use Xgpro v10.27 and it ask's me to update the firmware. When I run the firmware update from the Xgpro application is states "Reset Error! Please remove Programmer" and disconnects the device. Also when I run the System self-check I'll get an error. I'll need to figure this out somehow. (I have Windows10)

I haven't yet received my blank EEPROMS so I haven't yet tried to fire the motherboard with a fresh BIOS. However it would be interesting trying to read the old BIOS. Any clue what IC type it could be? Is it also W27C512 as the ones I ordered?

Parni wrote on 2020-07-27, 18:01:

I'm back! I got the TL866 Plus from China, however I think there are some issues with it. I'll use Xgpro v10.27 and it ask's me to update the firmware. When I run the firmware update from the Xgpro application is states "Reset Error! Please remove Programmer" and disconnects the device. Also when I run the System self-check I'll get an error. I'll need to figure this out somehow. (I have Windows10)

I haven't yet received my blank EEPROMS so I haven't yet tried to fire the motherboard with a fresh BIOS. However it would be interesting trying to read the old BIOS. Any clue what IC type it could be? Is it also W27C512 as the ones I ordered?

Have you checked whether you got a counterfeit ?

http://www.autoelectric.cn/EN/note.html