Re: My CPU Collection
Posted on 2019-01-31, 07:06
Something about the huge gold cap on the pentium pro with the enormous flashy logo amuses me. It's just so... huge.
Re: Help with Turbo button jumpers
Posted on 2019-01-31, 07:03
Simple example. If you want a digit to show '1' in deturbo and '7' in turbo, segments A and B need to be connected to 3 (vertical jumpers) and segment F needs to be connected to 2 (as only segment F will change). Everything else would be disconnected. If you want 7 in deturbo, connect segment F to …
Re: Help Replacing AT Case LED's
Posted on 2019-01-31, 06:53
I have never met a motherboard (or I/O card) header meant to drive an LED that wasn't current-limited. I actually used to have a very odd motherboard out of a pre-built generic computer from the 286 era that actually had resistors on the led cables. I traced the power LED header out of curiosity, …
Re: IBM 8503 Monochrome VGA Monitor Help
Posted on 2019-01-31, 06:47
Based upon a VGA pinout I've found on the internet and the silkscreen on the board, the pinout appears to be this: 5 pin connector, from the left side of the picture to the right: HS (white wire) - Horizontal Sync, VGA pin 13 VS (yellow wire) - Vertical Sync, VGA pin 14 SC (thin black wire) - See …
Re: DOS programs refuse to use CGA graphics modes
Posted on 2019-01-31, 00:08
hmmm, now edit.com and qb.exe default to 4 color monochrome, that's odd. It doesn't even give me an option to change it.
Re: 5.25" floppy drive problems
Posted on 2019-01-31, 00:05
hmmm, the floppy seems to have a bad sector. It won't image properly. Maybe try running "msd" in your dos folder and see if it has floppy test programs? I don't remember if it includes them.
Re: Help Replacing AT Case LED's
Posted on 2019-01-30, 22:51
Those leds are most likely the common 5mm type. If you have a soldering iron, you should be able to just replace those leds with some newer ones. It is possible that they have just grown dim with age. Just make sure to hook the led up in the correct polarity, though, or they will not work at all.
Re: Identification of 286 motherboard
Posted on 2019-01-30, 22:45
Thanks! Will try once I can bring myself to completely disassemble the PC for the 8th time this week.
Re: Identification of 286 motherboard
Posted on 2019-01-30, 21:49
root42 wrote: Happy little motherboard... I suppose that makes mine a sad little motherboard? 🤣 btw, any tricks to cleaning off that corrosion?
Re: Identification of 286 motherboard
Posted on 2019-01-30, 21:47
These wires from PSU are for connecting the LED segment displays on the case… Too bad about the ST-157A. These are mine favourite 40-45MB drives. Very reliable I recently purchased two of them. One looks and sound brand new (but of course been used). Other one sound a bit 'grinding' but works fine …
Re: Identification of 286 motherboard
Posted on 2019-01-30, 21:13
Also, I believe that those batteries are supposed to be 3.6v, not 1.2. At least that's what mine was labeled as when I removed it.
Re: Identification of 286 motherboard
Posted on 2019-01-30, 21:10
Yeah, your example is pretty nice. Totally not jealous. I got mine in its original case, a horizontal under-monitor type. It had an oak vga card, and a 40 mb seagate hdd. The power supply also had this stupid little .1 inch header socket wire that was on red/black wires for some reason. The HDD …
Re: .WAV player for MS DOS that runs on a 286?
Posted on 2019-01-30, 20:49
Interesting, didn't know 3.1 ran on a 286. Time to upgrade!
Re: Identification of 286 motherboard
Posted on 2019-01-30, 20:47
Here's a picture. It unfourtunately had the battery leak all over the board, and ruined the AT keyboard connector and I had to replace it. I scrubbed it down, but some corrosion remains on the ground pads.
Re: Identification of 286 motherboard
Posted on 2019-01-30, 20:34
holy crap that's my motherboard! (not mine exactly but it's identical to mine) What a strange coincidence, I just located the document on stason.org yesterday. I just ordered some simm sockets from ebay yesterday, here's the link. https://www.ebay.com/itm/Socket-Single-x-30pin-Simm-Vertical-Metal- …
Re: Help Replacing AT Case LED's
Posted on 2019-01-30, 20:27
Your motherboard *should* already have a current limiting resistor for each LED. All of my motherboards do, but I don't want to make a universal statement. My first step would be to test the LEDs by themselves. A safe current for LEDs of around that size is 15-20 miliampres, so with a voltage drop …
Re: Dallas battery replacement ?
Posted on 2019-01-30, 20:12
Np, always happy to help!
Re: Setting up internet/networking under DOS via ethernet?
Posted on 2019-01-30, 20:07
Almost everything you need to get a DOS based machine on the internet is here: http://www.brutman.com/mTCP/ The only other thing you need is the packet driver for your ethernet card, it should be somewhere on your install disk if you have it. That website has a great PDF that walks you through the …
Re: Dallas battery replacement ?
Posted on 2019-01-30, 19:15
The battery in the Dallas chip is a 3v button cell. A CR2032 should do just fine. As for the orientation, normally you can tell 1 of 2 ways which way the chip is supposed to go. The one I have has a little semicircle shaped notch about 1/16 of an inch wide on the bottom of the chip near one of the …
Re: Great Accessories for building Retro PCs
Posted on 2019-01-30, 18:58
I usually use one of those, but there is the occasional obnoxious one that has been stuffed right up against another component so you can only access one end of it. That's where the SuperJank Inc.© screwdriver method comes into play.
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