Explanation of XGA-1 functionality
9507 LCD Monitor
IBM SVGA Adapter/A
>>I would only need a single working 3151 (*serial* ASCII console IBM 3151)
>There lies the snag. You *might* be able to get one working one out of half a dozen duff ones. But Murphy's Law says that all of them will have the same fault.
The main failure on these terminals were:
Western Digital Video (Now Paradise)
Terminators for Enhanced video cards
From Brad Parker (out among the flat cornfields of Iowa)
This is the terminator that came with an M-motion adapter. I suspect that it would work equally well with the ATi Gup or any other auxiliary video card. Probably keeps the video drive amps on the unused card from going into oscillation.
The terminator requires three 75 ohm 1/4 watt resistors. As 75 ohms can be difficult at times to find, rest easy in knowing that the originals have a 20% tolerance, so any 5% tolerance or better resistor with an impedance between 63 and 100 ohms should work.
The resistors are wired in parallel between each color's drive pin and it's respective ground. In addition, the terminator keys the monitor ID to 0 by having a jumper between the 0 ID pin and digital ground. (Monitor Presence Detect ID=0); which together with opens on Pins 4, 12, and 15 (MPDID 1, 2, and 3) ensures that the system thinks an 8512 or 8513 (640x480 analog color only) monitor is attached.
Use a 15 pin male VGA connector and hood. The component values are as follows: R1-R3 75 ohm 20% 1/4 watt resistor J1 Insulated 24 gauge single conductor wire
Connect as follows:
Note the original unit has shrink tubing on the resistor leads-Not a
Will The he Real ATI GUP Terminator Stand Up?
In words, the system still thinks that an 8512/3 display is attached, but that the color signals are shorted to their respective grounds. I have no idea what the system or GUP logic decides about this. Maybe the 75-ohm load terminator and the dead-shorted terminator may be interchanged. Maybe not. There is an easy way to find out. QED.
Dead Short? Not My Pepperoni-Tuna Pizza!
Personally I want to add that a *short
circuit* (Null Ohm) between any of the RGB color signals and their according
GND returns is a bad idea. I would not recommend to use a "plug" that shorts
the video card outputs to GND with no resistor between. This could cause
damage of the video output drivers ... and if that video card is a planar-Video
you will probably need a new board
I picked up a couple of nice 9527 monitors for my Aptiva and Frankenclone. They work fine from a cold boot but when I do a warm reboot they always go blank after the BIOS and POST. The computer continues to look like it's restarting and then I get a totally garbled screen. (If anything at all)
I noticed this at work too, when I swapped a couple old machines out and put them on the IBM brand monitors. I've tried setting them to all the right settings in control panel.
Some oorts and leavings...
There are basically two types of "video support slots" available:
The Base Video must be present on any machine. Most machines have the base,video on the planar and therefore offer only slots with AVE - which enables *additional* cards to utilize the base video for synchronized output or low-resolution / text modes. (Famous notorious example: IBM 8514/A adapter)
Machines like the Mod. 95 which have no planar video offer both: BVE and AVE. A BVE-capable card like the XGA / XGA-2 *must always* be present to supply the base video functions initiated by the machine BIOS. A second card in an AVE-slot can be present.
On a Mod. 95 the Slot #5 is the BVE-slot to which a BVE-capable card must be present (short SVGA, XGA, XGA-2), Slot #7 is the AVE-slot, to which additional cards fit like IBM 8514/A, ATI, Spea or Matrox cards.