Re: Compaq Armada 1550DMT fun.
Posted on 2023-01-01, 17:08
Sphere478 wrote on 2022-12-31, 22:44: Re: Multiplier Bodge Board For laptops 486, Pentium, K6 , Cyrix. Made this for it 😀 But the P54C's BF pins are internally pulled-up.
Re: Help anyone with IBM PS2 and XGA card on MCA bus
Posted on 2022-12-29, 18:57
You probably have already noticed what XGA-2 adapter I have from this post, but to make sure there are no doubts - it's the first revision with a heatsinked RAMDAC (part number should be 33G0327ESD ) I have dumped the first 8KB of the UMA's C segment, where the XGA-2 BIOS is mapped on my machine. …
Re: Help anyone with IBM PS2 and XGA card on MCA bus
Posted on 2022-12-28, 14:45
I tried emulating an ESDI controller instead of SCSI, but the XGA-2 BIOS still wouldn't get resources allocated, for some reason you're not even allowed to change the ROM address range. However, I noticed one discrepancy when changing the address range of the SCSI ROM - it gets assigned 8000H (32KB) …
Re: Help anyone with IBM PS2 and XGA card on MCA bus
Posted on 2022-12-28, 02:16
You are welcome, keep up the good work ;) Out of curiosity, I created a virtual IBM PS/2 Model 80 in the "86Box" and enabled the XGA-2 adapter in the options. The first thing I encountered, when installing XGA-2 from the reference diskette, was a resource conflict, which manifested as an inability …
Re: Help anyone with IBM PS2 and XGA card on MCA bus
Posted on 2022-12-27, 21:10
I had a suspicion that it reads register values off an XGA adapter on an XGA-2 machine, this time values are different: XGA2 Index 52H value: 21FA; XGA2 Index 53H value: 2153.
Re: Help anyone with IBM PS2 and XGA card on MCA bus
Posted on 2022-12-27, 18:29
Just ran all of the provided tests on both machines and the following results were obtained: XGA machine: COMPID.EXE - Model: Unknown; PS2BUS.EXE - PoC: MC Bus; XGARD52H.EXE - Index 52H value: 21EA; XGARD53H.EXE - Index 53H value: 2130. XGA-2 machine: COMPID.EXE - Model: Unknown; PS2BUS .EXE - PoC: …
Re: Help anyone with IBM PS2 and XGA card on MCA bus
Posted on 2022-12-26, 23:48
let's hope it will output "FAIL" in "DMQS not supported" machines and "GOOD" in "DMQS supported" machine The result was exactly that - FAIL on the XGA and PASS on the XGA-2 graphics adapter. Adding full logs of both machines, some notes on hardware setup for completeness: PS/2 with an XGA-2: -Uses …
Re: Help anyone with IBM PS2 and XGA card on MCA bus
Posted on 2022-12-26, 20:02
Hi, I'm adding log files, collected from two separate Model 90 XP's. File "XGA.LOG" is generated by a PS/2 with an integrated XGA adapter, while "XGA-2.LOG" is generated by a PS/2 with an early XGA-2 adapter (heatsinked RAMDAC). XGA: Video Functionality/State Information …
Re: DOS start up sound
Posted on 2022-12-21, 15:13
I would use exactly this as the startup sound on my ripened cheddar 😐
Re: Compaq Armada 1550DMT fun.
Posted on 2022-12-19, 15:01
Where you able to find the datasheet for the MK1491-01 to ID the FSB resistors? Out of curiousity I had a quick look and I've only been able to find the -06, -09 and -14, and they're all very different (e.g. the -09 swaps the pin 1&4 Gnd and Vdd compared with the -06). Unfortunately, I could not …
Re: Compaq Armada 1550DMT fun.
Posted on 2022-12-18, 18:12
After OC, Vcore had to be bumped up by 0.02 Volts, otherwise applications, that required FPU, would crash.
Re: Compaq Armada 1550DMT fun.
Posted on 2022-12-18, 17:53
I have also overclocked my Armada 1550T to 166MHz, but I can only say one thing - CPU clock increase does not improve 2D graphics performance. In general, the entire armada 15XX series suffers from slow 2D graphics. These laptops are not that much faster and sometimes even slower than a 75MHz P1 …
Re: 486 board - no video
Posted on 2022-12-16, 19:43
This motherboard seems to have an ISA bus fault as none of the slots are working. A corrupted BIOS image could also prevent MB to complete a POST, but it's probably not it in this case. If fault is really in the ISA bus, then you can suspect: bad ISA bus address/data buffer chips, damaged tracks, …
Re: Help with Octek Fox M 286 (broken chip)
Posted on 2022-10-26, 00:38
You were almost there, the reference PAL chip had identical pinout and almost identical boolean equations, if only you hadn't procrastinated those 5 years 🤣 Good job crackintosh 😉 By the way, was REDLED's PAL dump compatible?
Re: Socket 7 200MHz test
Posted on 2022-10-26, 00:18
Awesome work! I separated benchmark part with Quake, here it can be noticed that all AMD K6 processors on the Gigabyte motherboard work slower than on DFI and such a difference (~3 FPS avg.) cannot be justified by the cache size alone. You can notice DFI's cache size advantage with the rest of the …
Re: Already programmed OTP EPROM?
Posted on 2022-08-15, 19:21
Don't bother with OTPs, better look for pin compatible EEPROMs, such as Winbond W27E512 or SST 27SF512.
Re: IBM PS/2 Model 70 PSU or HDD and Floppy drive issue
Posted on 2022-08-15, 18:14
I see, well, you'd have to temporarily solder a molex cable to the back of that edge connector or PSU PCB.
Re: IBM PS/2 Model 70 PSU or HDD and Floppy drive issue
Posted on 2022-08-14, 12:09
A sudden load change on the 12V rail seems to trip the PSU due to undervoltage condition. You can check that by turning on the PSU separately from the computer and loading 5V and 12V lines.
Re: XT clone motherboard repair advice/help needed (Jaton JXM-1003 / JXM-JET 88-V2)
Posted on 2022-08-04, 01:35
Cool! I can desolder this PROM and read its contents, but I'm not sure if this is necessary. Perhaps all this was done for the sake of some support for EMS memory of some early revision, but we are unlikely to find the original software. That PROM chip is just a fancy address decoder, most likely …
Re: XT clone motherboard repair advice/help needed (Jaton JXM-1003 / JXM-JET 88-V2)
Posted on 2022-08-02, 14:53
Great job! The whole picture is much clearer with that schematic at hand, based on it and 74f153 multiplexer chip, I think the generation of addr.8 and addr.9 signals or RAM should look like this: A8 = DACK & !SLAD & A16 # DACK & SLAD & A17 # !DACK & !SLAD & A8 # !DACK & SLAD & A8 A9 = DACK & !SLAD …
Page 2 of 31