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AST XFormer/286 BIOS Checksum error

Chuck(G): you are right the keyboard bios is actually a micro controller. It is labeled as Intel D8742 L8018541 '82. The GQ-4x4 will not read it and in fact there is no listing for it.

Sqpat: I uploaded the two BIOS files taken from the AST XFormer/286 motherboard. One's even and the other is odd. As you can see, the Keyboard BIOS is not readable as Chuck(G) pointed out.
 

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  • tms28c128 odd bios rom.zip
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Chuck(G): you are right the keyboard bios is actually a micro controller. It is labeled as Intel D8742 L8018541 '82. The GQ-4x4 will not read it and in fact there is no listing for it.
I have a GQ-4X and a Willem. To read/write the D8742, I have to use the Willem and an adapter.

Sqpat: I uploaded the two BIOS files taken from the AST XFormer/286 motherboard. One's even and the other is odd.
I have added those to the collection at [here].
 
I can put these on ultimateretro.com too. Is it possible to get an image showing the full motherboard that we could use?
 
Mr Slug: I have uploaded what I can to show details of the AST XFormer/286 Motherboard. If the first picture looks strangely like the brochure; that is what I used. I didn't want to pull the motherboard from the IBM 5162 housing. The others are closeups of my motherboard.

Modem7: I have a 40 pin connector on the GQ-4x4 EPROM read/write device. The problem here is there is no software on the system to match the D8742 chip to allow me to read the contents of the KBIOS from the chip. I checked with the manufacturer and I am using the latest upgrade to the product.
 

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I have encountered some difficulties with writing to a AM27128-4DC chip acquired for the Landmark Supersoft odd and even binaries. The True USB GQ-4x4 William Programmer seems to have only AM27128A in their listing. The problem I am experiencing is to load the Landmark binaries on to the chip. The error I receive after trying to write the binary is "Write Failed at address 0x000000 Buffer 0x43 Device 0xFF." I guess the GQ needs and adapter to write 16-bit binaries to the 16x8 EPROMs. Might be worth noting for anyone else trying the same procedure.
 
27128 is an 8-bit EPROM. You need two for 16-bit access, even bytes on one and odd bytes on the other. Make sure they are UV erased.
 
Most EPROM versions such as the 2764, 27128 and 27256 are UV erased. This 27128 is 16K words and 8-bit addressing. Yes, there are ODD and EVEN sets.. The manufacturer of the GQ-4x4 is recommending the adapter for multiple EPROMs such as the 27128. I have to go with the manufacturer of the GQ-4x4 to eliminate the error shown in the earlier post when writing to the EPROM.
 
I have tried that approach by selecting a Landmark Supersoft Even binary to install on the AM27128-4DC chip.

The procedure I follow involves using the UV eraser to erase the EPROM chip. Then I use the software associated with the GQ-4x4 read/writer to check to see if the chip is readable, which I see is all zero's. I then trigger Supersoft_AT_Even_27128.bin as the software, which I wish to install. Then I tell the writer to write the binary to the chip where-by-which is when the write error as displayed "Write Failed at address 0x000000 Buffer 0x43 Device 0xFF." I try this a second time and get the same error. I am at a loss to understand what the error means and how to correct it. As you said this is an 8-bit chip so I don't need an adapter. But, I am at a loss to correct the error.
 
The EPROM should read all 0xFF if it's erased. Does it pass the "blank check"?
 
I changed the binary read mode to even and tried to write with that setting and got a different buffer error =0X6F. if that means anything. Blank check remained the same as did device and address from the earlier try.
 
I have encountered some difficulties with writing to a AM27128-4DC chip acquired for the Landmark Supersoft odd and even binaries. The True USB GQ-4x4 William Programmer seems to have only AM27128A in their listing.
IIRC the AM27128 requires a programming voltage of 21V and the AM27128A requires a programming voltage of 12.5V. Double check that with the datasheets.
 
Then I tell the writer to write the binary to the chip where-by-which is when the write error as displayed "Write Failed at address 0x000000 Buffer 0x43 Device 0xFF." I try this a second time and get the same error. I am at a loss to understand what the error means
I have the GQ-4X, not the GQ-4x4, but presumably the subject error message has the same meaning.

DEVICE = The EPROM
BUFFER = In the context of a write operation, the data to be written to the device.

Background: 0x43 (43 hex) is the first byte in the even and odd SuperSoft ROM images.

So, the GQ-4x4 wrote 0x43 to the first address (0x000000) of the EPROM, but in verification, read back 0xFF instead of the expected 0x43.
 
IIRC the AM27128 requires a programming voltage of 21V and the AM27128A requires a programming voltage of 12.5V. Double check that with the datasheets.
Per below, shown in the 'Device selection' menu for my GQ-4X.

1651972507045.png

The True USB GQ-4x4 William Programmer seems to have only AM27128A in their listing.
As shown above for my GQ-4X, does your GQ-4x4 have a '27128' item in the 'ALL(GENERIC)' section ?
That may work for you.
 
Modem7: thank you for your feedback regarding the EPROM. First, the AM27128-4DC datasheet that I have doesn't show the VCC voltage. The datasheet mostly writes about the maximum temperature and speed of the EPROM. It's written in Chinese with some English for the voltages and currents of the data VD0 pins. I have put a PDF of what I found on this chip. To get a match of this chip from the GQ is not easy. I have been using all under Type, AMD as manufacturer, Device was limited to AM27128A and AM27C128. I may have missed the 27128 showing 21V. I saw a youtube video this weekend stating that a power adapter is needed for the GQ to program some high voltage chips. I don't have this adapter.

Since I wasn't having any success with the AMD chips, I am acquiring D27128 Intel chips. It may be a little more cooperative to install the Landmark software. I have uploaded the datasheet on that chip.

So out of curiousity, is there a way to test the voltage for the AMD chip or for that matter to test the chip to see if it is defective?
 

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  • Book291-89.pdf
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  • Intel D27128 datasheet.pdf
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You are going to need 21V to program the D27128. Even the 27C128 needs 12.5V to program. You should probably get the power adapter.
 
It may be more simple to get the AM27128A etc chips that require lower voltage. I know my USB programmer (the XGecu one) is also limited to 18V max.
 
Lots of options. For example, purchase 256Kbit PROMs and program them with 2 copies of the data. Or use the CMOS variant of the 128 - 27C128 or use a 256kbit flash PROM (29C256)...
 
Since I wasn't having any success with the AMD chips, I am acquiring D27128 Intel chips. It may be a little more cooperative to install the Landmark software. I have uploaded the datasheet on that chip.
The Intel D27128 requires the same programming voltage ( VPP ) of 21V, You will probably be better off getting a CMOS 27C128 Eprom which will have a lower VPP, What is the make of your original BIOS chip.
So out of curiousity, is there a way to test the voltage for the AMD chip or for that matter to test the chip to see if it is defective?
This is where i prefer to use my old Data I/O programmers for old chips, They actualy kick out a meaningful error message if a faulty chip is inserted / detected.
 
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