Built myself a 486

[eightbit]

My wife came home today from shopping and said "hey, there's a CRT monitor on the side of the road the town over" so I hopped in the car for the two minute ride to see if it was worth it. Yeah, worth it

 

This makes the second CRT monitor in my collection. Both found on the side of the road which is odd since the garbage in my area will NOT pick these up. You have to pay the town $20 for pickup or drive it down yourself. That said most people know the rules and you never see stuff like this in my area on curbs. The last CRT I found (the main monitor I use) is a Starlogic 21 inch I found back around 4 or 5 years ago. Have not found another locally at yard/garage sales at all. Thrifts in my area haven't allowed acceptance of CRT monitors or TV's for years either. So, this was a lucky find.

 

 

[+OLD CS1]

1 hour ago, eightbit said:

Both found on the side of the road which is odd since the garbage in my area will NOT pick these up.

Most residential waste disposal will not pick up CRTs, but people still put them out there. Works for me, too, since I have picked up two 32" TVs in the past year.  As well, most places like Goodwill and thrift stores around here will not accept CRTs, as well as none of the commercial sites (like BestBuy) will accept them for recycling.  The only place to take them now is municipal electronics recycling events or hazardous waste at the local landfill.

[eightbit]

5 minutes ago, OLD CS1 said:

Most residential waste disposal will not pick up CRTs, but people still put them out there. Works for me, too, since I have picked up two 32" TVs in the past year.  As well, most places like Goodwill and thrift stores around here will not accept CRTs, as well as none of the commercial sites (like BestBuy) will accept them for recycling.  The only place to take them now is municipal electronics recycling events or hazardous waste at the local landfill.

 

I think electronic recycling centers should rethink their recycling. I think they should take items in and allow people to come and browse the inventory....and then dispose of what is not taken away. My recycling center will NOT let you take anything. There's a mean guard there that watches you dump whatever you want....but God forbid if you touch anything that is already there. 

 

I personally believe the best way to "recycle" electronics is to give them an opportunity at a new life with a new owner first. It may be trash to someone but treasure to someone else. There is no reason to destroy things that can still be used by someone.

 

 

Edited April 16, 2022 by eightbit

[Keatah]

Liability.

[wierd_w]

I get that we live in a litigious society, but jeeze-- what part of "It is literally trash that somebody else threw away." in any way implies liability for ... anything?

 

There isn't even grounds for Magnusson-Moss "Fit for purpose" limited liability there!!  You could take it home, and find that it is full of rust, cat piss, and dead cockroaches/bedbugs for crying out loud.  That is the risk you take when you pick up old stuff like that.

[+OLD CS1]

10 hours ago, Keatah said:

Liability.

EPA rules.

9 hours ago, wierd_w said:

There isn't even grounds for Magnusson-Moss "Fit for purpose" limited liability there!!  You could take it home, and find that it is full of rust, cat piss, and dead cockroaches/bedbugs for crying out loud.  That is the risk you take when you pick up old stuff like that.

We are not permitted to take on our own risk. In some places, you are not even allowed to take home certain items, CRT TVs and monitors are one, which you find at the curb. Nothing about litigious society, it is about a nanny-state society. This, however, runs the risk of taking this thread off the rails.

[Keatah]

Busywork. Overzealous & overactive clerks and small-town lawmakers see a gap somewhere and get gung-ho on doing something just to do it.

[eightbit]

Back on topic:

 

I found some 4MB DRAM modules in storage by PNY. As most already know, I work there

 

So, I had to get them into this machine. I decided to move the memory down from 32MB to 24MB. Not that 32Mb of memory was causing any issue...it was really just overkill. Most people will say 16MB is the sweet spot and previously I would have agreed. That was until I started investigating the demo scene and found some really cool DOS demos that demand 20 or even 24MB of memory. I haven't however found any demo or game yet that needs more than 24MB from the era of what this machine is capable of running.

 

That said, I am considering 24MB to "right spot" for this rig. Now it has the two 4MB PNY modules I found as well as one 16MB module. Thoroughly tested with Memtest 4.10 and no issues after multiple passes. Funny how durable the older memory is. I have lots of old DRAM and EDO DRAM memory that works just fine and some of it has not been stored in the most ideal of conditions. But it always seems to work just fine. 

 

 

Edited April 19, 2022 by eightbit

[wierd_w]

I tended to allocate a very generous smartdrv cache on large memory systems.  Entire FAT tables could live in it, and it made a pretty demonstrable difference BITD.

 

 

[Keatah]

I purchased my 486 with 4MB of RAM. And a year or so later upgraded to 8MB and then weeks later 16MB. Pretty sure that's how that went down. Man when I strolled into CompUSA with $200 in-hand I felt like a million bucks! I walked outa there beaming with 4x 1MB SIMMS. There could've been an alien invasion and I wouldn't a-noticed.

 

There are 16x 30-pin SIMM memory slots in the rig. 8 on the motherboard. And 8 more on a propriety (but very simple) card. Each slot supports 1MB or 4MB modules for a grand total of 64MB. From the looks of it the card is just a buffered extension of the on-board slots. A few LSxxx parts, resistors, and caps. And it is compatible with Micronics' 386 motherboards too.

 

Today I deemed myself lucky to have purchased it because I've only seen it on ebay one time in years and years of searching, including those automatic email alerts. The lesson I learned in the Apple II days - get any proprietary/specialized accessories with the main purchase, since they won't be available later on.

 

There are many overtones of 286/386 design on this 486 motherboard. The two-chip BIOS. The CHIPS 82C206 Integrated Peripheral Controller representing a block of circuitry from the 286 PC/AT era. Includes things like DMA/Interrupt controllers, timers, realtime clock, 64 bytes of CMOS memory. And a memory mapper from the TMS9900 era (74LS612). There are no onboard I/O peripherals like drive controllers or serial/parallel ports. But there's 8 ISA slots. Has a Weitek Abacus 4167 socket. Though I don't know why anyone would use it, maybe to complement a 486SX? I still want one for completion sake.

 

While I'm sure there was cost-cutting going on in 1992, I didn't really observe much with this board. It's rather densely populated without a lot of empty space. Conforming to the baby AT spec. It would fit in an Apple II case if low-profile cards were used. Nothing I would entertain beyond a humorous thought experiment.

 

So.. I kept the system at 16MB. Partly out of nostalgia and partly that being the proverbial sweetspot. Nothing I did warranted more than 16MB anyways. I stuck with the 1MB SIMMS for consistency sake. 16 SIMMs! My god!

[eightbit]

That just sounds awesome. I have seen those motherboards with large amounts of SIMM sockets....but only in pictures. I don't think I have ever had the pleasure of working on one and I certainly never owned one. 

 

This memory (all memory) was extremely expensive back in the day as you are fully aware. I recall installing memory sales at Computer City when I worked there in the 90's and I saw people spend a LOT of money on RAM. 

 

Years later when I ran my own store I had quite a few customers that didn't want their old RAM after an upgrade and would tell me to either keep it or scrap it. It was still worth quite a bit too. I had so much of it that I took it to a location a town over that was similar to a check cashing place, but they purchased used RAM at top dollar! Someone tuned me into the place and I couldn't believe at the time a place like that existed. But, I guess there was just this demand for RAM at the time....so much so that places like that could exist.

 

 

[eightbit]

BIG changes. I know I said I was done...and I was. That was until the opportunity arose to make a trade and get myself some things I really wanted for this 486...and the upcoming Pentium build.

 

You'll notice a big long red ISA board in here now. For those unaware of what that is (and I bet most are aware) that is a Gravis Ultrasound Max. I really wanted to check out games and just as important to me the demos that utilized this strange but cool sound card. 

 

In the same trade I received a Soundblaster CT1770...the oldest Soundblaster I have to date. I always loved the volume knob on the back of these. And of course the midi-bug free DSP and the extreme compatibility. This one has a wavetable header so if you look really close you will also see a Dreamblaster X2GS wavetable board connected

 

I will not go into the absolute headache it was to get both sound cards in this machine shaking hands nicely, but after a half a day of farting around I finally got it. I have them both connected to an audio switchbox so I can flip to Ultrasound or to Soundblaster on the fly. And they both work properly. I heard stories of people not being able to get adlib sound or whatnot when trying to pair them, but I guess I am lucky and I found the right special sauce to make this happen.

 

So I spent the day (while not working that is!) testing and playing various games and demos both for the Soundblaster and General MIDI and the GUS. And it is wonderful. I still have some of the tunes from Future Crew demos playing through the GUS stuck in my head as I type!

 

 

[wierd_w]

Well, if you want to forsake having a printer port I guess that's one way to deal with the Gravis Ultrasound's "not terribly great" soundblaster emulation modes.

 

(It wants to live on either IRQ 5 or 7, which happen to be the IRQs used by printer ports.  With both a soundblaster and a gravis ultrasound present, that means both IRQs are in use, and thus, no printer port.)

 

For the advanced wavetable features of the Ultrasound (which allowed realtime upload of new instrument sets LONG before creative labs' AWE and soundfonts, and many games from the era could make use of this for very improved music reproduction), I can see how this would be a desirable feature. Personally though, I think the LPT port is not something I would compromise on. (its too useful of a port in vintage systems.)

[eightbit]

33 minutes ago, wierd_w said:

Well, if you want to forsake having a printer port I guess that's one way to deal with the Gravis Ultrasound's "not terribly great" soundblaster emulation modes.

 

(It wants to live on either IRQ 5 or 7, which happen to be the IRQs used by printer ports.  With both a soundblaster and a gravis ultrasound present, that means both IRQs are in use, and thus, no printer port.)

 

For the advanced wavetable features of the Ultrasound (which allowed realtime upload of new instrument sets LONG before creative labs' AWE and soundfonts, and many games from the era could make use of this for very improved music reproduction), I can see how this would be a desirable feature. Personally though, I think the LPT port is not something I would compromise on. (its too useful of a port in vintage systems.)

 

Nope, the GUS is using 11, which was free and it works just fine. The printer is still active. This is the "Max" version of the card, its a little different. It is like part PnP and part non-PnP. I/O is selectable by jumpers, but IRQ/DMA by software. But unlike the Gus PnP card (the actual PnP card) this does use the GF1 chip which is great.

 

Actually, it is using IRQ 11 and 12 to be correct. This card will consume two IRQ's, one for the GUS itself and one for MIDI playback. I set it up on both since 11 was free and 12 which is normally used for a PS/2 port is unused as well. This board does have a PS/2 header but I never used it and it is disabled as I use a serial mouse anyway. A screenshot of the setup is attached so you see what I mean (not mine, just one I found randomly in an online video just to illustrate)

 

It was the I/O selection that was problematic with this machine. When I chose 0x260 (this is jumper selectable) it would lock up randomly or not start a game with GUS sound, etc. I know choosing 0x260 also uses 0x360 on the GUS cards, so maybe something else was bumping against it somewhere. I moved it to 0x240 and that resolved that issue.

 

Its certainly a quirky card for sure. But now that I have experienced it I can't ever find myself removing it. It just sounds great for those things it was designed for. Doom actually sounds pretty good, as well as Hexen (just two random games I selected the GUS in just to see how it sounds). Jazz Jackrabbit sounds amazing. And of course the demos (which really was the primary reason I wanted one of these in here) are truly mindblowing when using the GUS. I was previously running for example the Future Crew Second Reality demo using SB Pro 2.0 emulation on a more modern card and that really sounded great. But, not anything like the GUS, that is for sure.

 

 

Edited May 4, 2022 by eightbit

[wierd_w]

Well, if you have it working, and still have a functional printer port, I am pleased along-side you.

 

Just dont try to add a network card, or another IDE controller.

[eightbit]

6 minutes ago, wierd_w said:

Well, if you have it working, and still have a functional printer port, I am pleased along-side you.

 

Just dont try to add a network card, or another IDE controller.

 

Or add an anything...lol

 

The tricky part that you don't see is the next screen tests for DMA 1 to be available. It gives you no option. DMA 1 is owned by the GUS, period. So I had to go back into the SET BLASTER variable and move it to DMA 0. 

 

But, yeah, it works. I tested some games that would have caused some issue in my mind (like Keen 4 and Wolfenstein) and they are fine using the SB. 

 

I only have the GUS as the primary sound card in Windows 3.1 however but I really don't want to "break a good thing" so I guess in Windows 3.1 it's GUS all the way! Hah..

 

On the DMA 1 issue, one youtuber said "this is a bug, just ignore". No, it is not. Ignoring it causes some game sound issues. Once I moved the DMA for the SB off of DMA 1 this test passed. (another screenshot from that video online)

 

Edited May 4, 2022 by eightbit

[wierd_w]

(not everyone who might be following this thread is a hardcore retro PC nerd like me, so this is just "out there" for general knowledge awareness.)

 

IRQ 0 is the system timer

IRQ 1 is the keyboard controller

IRQ 2 is reserved for cascading the programmable interrupt controller, with IRQ 9 (and thus not available on AT class systems)

IRQs 3 and 4 are for serial ports 2/4 and 1/3 respectively.

IRQs 5 and 7 are for LPT ports 1 and 2 respectively, but also used by sound cards and other add-in cards.

IRQ 6 is the floppy diskette controller.

IRQ 8 is the RealTime Clock

IRQ 9 is the other side of cascaded IRQ 2, and thus not normally available in vintage machines. Sometimes VGA cards will use it though.

IRQ 10 is usually free. It tended to get used by tertiary (as in, the third one) IDE controllers (like the one baked into a soundblaster 16/AWE 32), NIC cards, and HSC winmodems. (Especially winmodems)

IRQ 11 is usually free, it tended to get used by IDE controllers and network cards. (Especially NIC cards)

IRQ 12 is 'sometimes' free;  It is used by a PS/2 keyboard/mouse controller, and or, (in later pentium boards) USB controllers.

IRQ 13 is used by the floating point arithmetic unit.

IRQ 14 is the primary hard disk controller.

IRQ 15 is the secondary hard disk controller

 

Not all vintage sound cards could be coaxed to live on IRQ 10 or 11, like apparently this GUS MAX can.  This usually just leaves 5 and 7 available for soundcards.  Since LPT ports cannot operate without an IRQ, this usually meant disabling the LPT ports.  In systems that were really crowded with expansion cards, disabling COM Port 2/4 (to get IRQ 3) was a common practice. I did that more than once to get a 3COM NIC set up and working in old vintage boxes, BITD.  That still left COM1/3 open for a serial mouse, left the printer ports alone, etc.

 

 

 

 

 

Edited May 4, 2022 by wierd_w

[mr_me]

Unless you are printing while using digitised audio, a sound card and printer port can both be set to use IRQ7.  This was typical in early PC days as early hard drive interfaces used IRQ5.  Later when Windows became more popular Sound Blaster cards defaulted to IRQ5.

 

You can set a network card to use IRQ9.  You just can't use IRQ2 for something else as IRQ2 and IRQ9 are tied together.

[eightbit]

23 minutes ago, mr_me said:

Unless you are printing while using digitised audio, a sound card and printer port can both be set to use IRQ7.  This was typical in early PC days as early hard drive interfaces used IRQ5.  Later when Windows became more popular Sound Blaster cards defaulted to IRQ5.

 

You can set a network card to use IRQ9.  You just can't use IRQ2 for something else as IRQ2 and IRQ9 are tied together.

 

That is true. I only personally have LPT1 enabled for posterity. I do have an parallel port scanner I found new on box at a Goodwill some time ago for a buck that I may play with some day for kicks, but personally I will never see myself using the printer port otherwise.

 

I could actually free up more resources by disabling that and COM2 if I wanted as both are just "sitting there" in this machine. 

 

I have always tried to "make it all work" first however before opting to disable things of course, but the options are there if I need them. 

 

I have always had a knack with handling resources on machines. When I worked as a PC tech in the 90's I was the go to tech when the other techs couldn't get customer machines fully functional. And then PnP came along which gave them much less control but I was still able to make it happen however sometimes it meant moving cards around just to make Windows happy. And those stupid PnP modems creating nonsense COM ports after too many installs (COM5, COM6, etc.) I had the location for that in the registry to fix that memorized. Fun times!

 

[zzip]

10 hours ago, eightbit said:

In the same trade I received a Soundblaster CT1770...the oldest Soundblaster I have to date. I always loved the volume knob on the back of these.

It's really inconvenient though.   Always hard to reach anything on the back of a PC once it's hooked up and running

 

10 hours ago, eightbit said:

will not go into the absolute headache it was to get both sound cards in this machine shaking hands nicely, but after a half a day of farting around I finally got it. I have them both connected to an audio switchbox so I can flip to Ultrasound or to Soundblaster on the fly.

You might want to look into the Ultrasound ACE if you can find one.   It was designed to coexist with another soundcard.   It does not have the CD-ports, game ports or any of the other extra features.  It leaves your other soundcard to do all that, it only provides the wavetable and digital audio.   It will also pass-through the output of your other soundcard so no need for audio switchbox.   You can even configure games to play sound through soundblaster and music through GUS (or vice versa) and both cards will play through the same speaker.

[zzip]

8 hours ago, wierd_w said:

(not everyone who might be following this thread is a hardcore retro PC nerd like me, so this is just "out there" for general knowledge awareness.)

I used to know the IRQ purposed like the back of my hand.   But it makes me wonder if modern PCs still use the same IRQ scheme or expanded it in some way to prevent conflicts?   It never seems to be an issue for end-users anymore.   I know pnp helped, but that can't stop you from running out of IRQs if you put too much hardware in your system.   Or maybe because serial ports, parallel ports and floppy drives are uncommon now that makes more IRQs free?

[wierd_w]

64bit machines have a LOT more IRQs.

 

Quote

Newer x86 systems integrate an Advanced Programmable Interrupt Controller (APIC) that conforms to the Intel APIC Architecture. These APICs support a programming interface for up to 255 physical hardware IRQ lines per APIC, with a typical system implementing support for only around 24 total hardware lines.

 

https://en.m.wikipedia.org/wiki/Interrupt_request_(PC_architecture)

 

This is in addition to the abstracted PCI bus slot IRQs, A B C and D.

Edited May 4, 2022 by wierd_w

[eightbit]

And that's why the kiddies today can just slap systems together without a care in the world...or any real computer knowledge at all.

 

Years ago when I was a call center tech we had this guy installing dual GTX 580's in SLI and building a "super rig" that had some issues. I asked him at one point to enter the BIOS for something and he said "what's a BIOS?". I said "do you mean to tell me you built this entire system on your own but never entered the BIOS setup for anything?". He said "yup".

 

 

[Keatah]

PCs have too many volume controls.

 

1) sound card knob

2) external speaker dial

3) windows/dos mixer, w/multiple points

4) the application itself

 

Edited May 4, 2022 by Keatah

[eightbit]

11 hours ago, Keatah said:

PCs have too many volume controls.

 

1) sound card knob

2) external speaker dial

3) windows/dos mixer, w/multiple points

4) the application itself

 

 

Options!