I believe the two FIC 486-GAC-2 motherboards I got belong to one of the systems in title. I suspect the no video at boot issue is related to the fact that I don't have the ISA riser, which might be necessary for the proper working of the ISA bus. I am unfamiliar with 486 systems so please help me with this sanity check: is it common for a board to require an ISA riser to wake up its onboard video chip?
Here is the picture of the board: http://www.motherboards.org/mobot/motherboard … /FIC/486-GAC-2/
The riser slot looks like a 16bit ISA slot without the 8/16bit separation key (there are pins at where the key used to be), and it can work properly with an ISA video card inserted in.
lazibayer wrote:I believe the two FIC 486-GAC-2 motherboards I got belong to one of the systems in title. I suspect the no video at boot issue i […] Show full quote
I believe the two FIC 486-GAC-2 motherboards I got belong to one of the systems in title. I suspect the no video at boot issue is related to the fact that I don't have the ISA riser, which might be necessary for the proper working of the ISA bus. I am unfamiliar with 486 systems so please help me with this sanity check: is it common for a board to require an ISA riser to wake up its onboard video chip?
Here is the picture of the board: http://www.motherboards.org/mobot/motherboard … /FIC/486-GAC-2/
The riser slot looks like a 16bit ISA slot without the 8/16bit separation key (there are pins at where the key used to be), and it can work properly with an ISA video card inserted in.
Hallo,
I have both, G-510 and G-515 in good conditions.
Jaromir
I have the Globalyst 515, but I never tried running the computer without the ISA riser card, although I *THINK* I saw a jumper to enable/disable the on-board graphics chip. Don't quote me on this though, but I'll have a look at the computer later.
What I would really like to do is locate the damn cache card to insert into that brown slot at the front of the CPU socket. My Globalyst 515 uses a 486DX2-66 exactly like my current 486 build, but without any motherboard cache, the Globalyst 515 is a lot slower. In fact, I wouldn't mind getting a pinout for that stupid plug and recreating the cache board.
Creator of The Many Sounds of:, a collection of various DOS games played using different sound cards.
I have the Globalyst 515, but I never tried running the computer without the ISA riser card, although I *THINK* I saw a jumper to enable/disable the on-board graphics chip. Don't quote me on this though, but I'll have a look at the computer later.
What I would really like to do is locate the damn cache card to insert into that brown slot at the front of the CPU socket. My Globalyst 515 uses a 486DX2-66 exactly like my current 486 build, but without any motherboard cache, the Globalyst 515 is a lot slower. In fact, I wouldn't mind getting a pinout for that stupid plug and recreating the cache board.
Here´s just an addition / a solution for the problem described above:
The onboard graphics of a FIC 486-GAC-2 is disabled and cannot be enabled without the original and proprietary ISA riser card being inserted.
1. Easy solution: Don´t bother, just put an ISA graphics card in the ISA slot, or, if you intend to use other ISA cards like a NIC, insert some standard 98-pin ISA riser card and populate it with a video card, NIC, whatever.
2. Workaround if you want to use the onboard graphics and leave the ISA slot empty (or if you need all slots of the riser card otherwise) you have to "mod" the mainboard to force it to enable onboard graphics:
FIC decided to use the 6 pins of the ISA slot that are situated in the notch between the 8-bit slot and the 16-bit extension slot.
the 3 pins between "A31" and "C1" are connected to ground.
the 2 pins following "B31" are connected to 5V (Vcc) as additional power supply for the riser.
The pin between these 2 pins and pin "D1" of the 16-bit extension is the switch for enabling internal graphics. (FIC probably wanted to make sure that it´s impossible to enable 2 ISA graphics at the same time.)
As soon as the proprietary riser is inserted, this pin is pulled to ground. Then and and only then it´s possible to enable the onboard graphics using the first switch of "SW1".
If a graphics card is inserted in the riser, the pin is released and is pulled up to Vcc by the mainboard logic, the onbord graphics is then forced to being disabled no matter what the position of "SW1" is.
So to manually force the onboard graphics to being enabled, just put a 1KOhms resistor from this ISA pin to ground. Make sure, no second graphics card is inserted without first manually disabling the onboard graphics chip with "SW1".
For no logical reason the second switch of "SW1" needs to be set to "monochrome", otherwise there´s an error beep at start up ("long -short-short-short", bad video memory or video adaptor)
This switch is connected to a pin of the Intel "N8224PC" microcontroller, that I´m not even able to find a datasheet about.
(Maybe the description in the silkscreening is wrong.)
