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First post, by Intel486dx33

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Hi, I have a computer to restore. It is an AST Bravo LC2 4/33s. ( Model 173m )
Made in USA by AST corp. of Texas I think. But they where head quartered in LA. California.
This must have been the first model Multimedia PC build by AST.

Build date is 1993 I think but this would have been a very expensive computer back in 1993. ( Dec 28, 1993 ).
I want to restore it to original.
It has an AST motherboard ISA.
128kb cache. Has strange cache ram holders.
Onboard 486sx-33 CPU and Overdrive CPU socket.
NOT sure how much ram it supports.
I want it to run DOS and Win3x.
It has a Media Vision sound card, PAS16 ( Made in USA )
2x Sony CDROM drive. ( Original Media Vision sound card and CDROM setup ).
Onboard video is Cirrus logic CL-GD5424 ( 1mb. ).
Onboard IDE controllers.
For Network card I will probably add an Intel-Pro-10 or 3com 3c509
I plan on adding a 540mb IDE hard-drive. Most likely WD.
( MT ) Micron ram made in USA.
It has an onboard Intel 486sx CPU and an Socket for an upgrade CPU.

Does anyone know of the original config for this computer or marketing add or manual ?
What CPU upgrades do you think will work in this computer ?
Was this computer under powered for a Multimedia computer ? I think so.

Computer specs with upgrades: CPU - Intel 486dx2-66 RAM - 16mb -60ns ( FPM ) Cache - 256kb Harddrive WD-540mb Audio - Media Visi […]
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Computer specs with upgrades:
CPU - Intel 486dx2-66
RAM - 16mb -60ns ( FPM )
Cache - 256kb
Harddrive WD-540mb
Audio - Media Vision PSA16
Video - Cirrus Logic CL-GD-5424 ( 1mb )
CDROM - Sony 2x

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Last edited by Intel486dx33 on 2020-01-25, 20:03. Edited 12 times in total.

Reply 1 of 19, by Intel486dx33

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Well, I was able to upgrade the CPU to an Intel 486dx2-66 using the over drive socket.
And I upgraded the ram to 16mb.

I still need to get this CDROM drive working. The sound card works but I cant seem to get the Sony CDROM drive to work.

Reply 2 of 19, by SirNickity

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Seems to be nearly identical to the AST Advantage! Pro 486SX, with merely a different front bezel and drive bay arrangement:

astadv.jpeg
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This one isn't mine -- borrowed the image from RetroSteamTech's blog. Mine is still the "before" picture, heavily yellowed and with a crack under the 3.5" floppy bay.

I have the SX/25 model. When it boots up, the BIOS even IDs itself as "LC". 😀

I have found very little online about the Advantage series. The Bravo line seems more prolific. But you're right, they are a bit anemic. This is a re-buy of my first PC, although my original was a notch down -- SX/25 with 85MB WD Caviar HDD and 2MB RAM. I bought it new for $999. The one I have now is similar to your config -- 170MB WD Caviar HDD, 4MB RAM, Cirrus 5428 video. No stock sound card or CD-ROM, though.

I have added a PAS16, since back in the day I had used my dad's hand-me-down SB Pro 2.0 until I got the Media Vision Pro Audio Studio 16 for Christmas. Never had a CD-ROM in this PC. The previous owner of my new one had added an SB16 and Goldstar 8x IDE CD-ROM, which I took out and used elsewhere. It also came with a modem. I left that in (for no good reason except that it appeared to be original) and added a 3Com 3C509.

I've also added another 4MB stick of RAM for a total of 8MB. For a brief moment, I had installed an additional 16MB stick for a total of 24MB. It passed Memtest86 just fine, but it took a little longer to boot counting all that RAM, and frankly, it just doesn't need that much.

I hope you already have that 540MB drive. 😉 I tried a 720... 750.. 7-hundred-something MB, but the BIOS is capped at 1024x16x63 CHS. It works (limited to the BIOS cap), but I hate to waste the extra capacity, so I just picked up a Caviar 2420 (425MB) which arrived today -- even has an AST part number on a sticker. 😀 I would've liked to have the extra 120MB of a 540MB drive, but the retro community is quite determined to hit that CHS ceiling, so they're always way more rare and expensive than their 420MB equivalents. I'll make do.

There's an OEM version of DOS 5 for these (see WinWorld for information about this on their DOS page), which interestingly, seems to be MS-DOS with IBM-style naming convention for the kernel files. IIRC, mine shipped with stock Windows 3.1 disks, MS Works 3.0, and an "AST VGA Drivers and Confidence Test" floppy. I found an image of the latter, but it's not the correct one for my model. The drivers look to be for a Paradise VGA chipset, I think, and do not support 1MB video RAM based on the resolutions available in the OEMSETUP.INF file. The confidence test works fine, though. (If anyone has an image for this disk that has Cirrus drivers, I would love to know! In the meantime, I'll use generics and hope I run across my original disk some day.)

Mine shipped with the mouse in the image above -- a Logitech re-brand -- and an AT keyboard be SEJIN, similar to this:

s-l1600.jpg
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The only difference being, mine has a dark gray overlay around the LEDs and printed AST logo on the top left corner above the Esc key. I just took mine apart and gave it a thorough cleaning -- looks good as new. I don't have a picture of it, though -- hence the Ebay image rip. I played with this PC a bit last weekend and it is an absolute joy to use. It's whisper quiet, and typing on that keyboard feels like catching up with an old friend.

Reply 5 of 19, by SpectriaForce

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Are you sure the CPU is a 486DX and not a 486SX, because mine has the latter one originally. That would make sense because of the 's' in the model name. Besides does yours also have a VLB slot? (update: I see yours has an entirely different motherboard!)

I sell 'ridiculously expensive' retro hardware to people like you. I feel sorry for that.

Reply 6 of 19, by Intel486dx33

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SpectriaForce wrote:

Are you sure the CPU is a 486DX and not a 486SX, because mine has the latter one originally. That would make sense because of the 's' in the model name. Besides does yours also have a VLB slot? (update: I see yours has an entirely different motherboard!)

This computer came with an onboard Intel 486sx-33mhz CPU
I changed the jumpers and used a standard Intel 486dx2-66 CPU in the over drive socket.

Manual here:
http://www.uncreativelabs.de/th99/m/A-B/31980.htm

Upgraded the ram with one stick of 16mb ( 60ns, FPM )

The only thing I was NOT able to upgrade was the cache. I tried several types but could not get the motherboard to recognize the cache.
I don't know what type of cache will work with this motherboard bios ?

Reply 7 of 19, by pentiumspeed

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you need matched set of 9 pieces of 32K x 8 SRAM cache chips 25 or 20ns, or 15ns for fsb of 33mhz. All matched. Tag tend to be 5ns faster but if 15ns, just use all 9. Close all cache jumpers with 3 pieces of jumpers.

Or buy a motherboard with 9 pieces of cache configured for 256K and transfer.

Try not to buy from chinese sellers.

Like this:

https://www.ebay.ca/itm/AS7C256-15PC-ALLIANCE … LoAAOSwQ4Rdwhw3

https://www.ebay.ca/itm/W24M257AK-15-WINBOND- … LMAAOSwNlldwLHv

https://www.ebay.ca/itm/UM61256FK-15-UM61256F … UQAAOSwPAxaTEKw

Cheers,

Great Northern aka Canada.

Reply 8 of 19, by Intel486dx33

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Well, I don't know if I will be able to get the original Sony 2x 30-pin CDROM drive to work which is connected to the Media Vision PAS16 sound card.

So what should I do?

Keep the original Media Vision PAS16 sound card and use an 40-pin IDE CDROM
or
Use a Sound Blaster 16 CT2950 with IDE CDROM ?

Reply 9 of 19, by SirNickity

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What's the issue with the CD-ROM? My Sony 2x put up a bit of a fight with an SB16 MCD, but I got it working eventually. For one, I never could get a floppy cable (34-pin) working with it, and ended up crimping a new straight-through 34-pin cable instead. Not sure what difference it would've made, since AFAIK a floppy cable is 100% straight through without any shenanigans (aside from the twist.) Could have just been a dodgy cable.

Reply 10 of 19, by Intel486dx33

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SirNickity wrote:

What's the issue with the CD-ROM? My Sony 2x put up a bit of a fight with an SB16 MCD, but I got it working eventually. For one, I never could get a floppy cable (34-pin) working with it, and ended up crimping a new straight-through 34-pin cable instead. Not sure what difference it would've made, since AFAIK a floppy cable is 100% straight through without any shenanigans (aside from the twist.) Could have just been a dodgy cable.

I am NOT sure if it the CDROM drive that is bad or the the driver installation.
But I think the CDROM drive is bad. It does NOT read disks, It does NOT eject, The Green LED ( read disk indicator ) is alway on.

In this AST computer which has a Media Vision PAS16 sound card and Sony 2x CDROM drive attached. At boot the Media Vision sound card driver loads okay but when the CDROM driver tries to load I get an error message that reads " No CDROM drive found, Check cables or power connection"

I don't know if I need a special setup for this Media Vision sound card because I am just using the Sony driver specific to this CDROM drive.
Do I need a special setup for it to work with the Media Vision sound card connector ?

Reply 11 of 19, by SirNickity

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... probably. My PAS16 has a SCSI port, so I'm not sure if the MVSOUND.SYS uber-driver has any code to handle the Sony interface. In the case of the SB16 MCD, I had to use the Sony driver and point it at the right base address. I believe it was 220h + 10h -- it's the same for all the proprietary interfaces.

I have a tower with one of each of the Sony, Mitsumi, and MKE drives, and made a custom dual-headed cable that I can just move between the 40- and 34-pin connectors on the card and the corresponding drive. I got them all working at one point, so I can check my boot disk to figure out what settings I used. That said, I don't know at what address the MV card would connect the Sony interface, nor for certain whether it has to be enabled by an MVSOUND parameter or if it's just connected directly to the bus.

I can tell you that the drive LED is supposed to stay on, though. That's perfectly normal. It blinks or changes color with activity - I don't remember which. Not being able to eject is slightly more concerning, as I think mine does any time it's powered. However, it's a simple solenoid eject that just releases the tray, not a normal tray-loading mechanism. I.e., if there IS something wrong, it could be a very simple fix.

Reply 12 of 19, by Intel486dx33

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I like it !...
Runs smooth and quiet.
I upgraded the CPU to Intel 486dx2-66 , 16mb ram and 540 WD harddrive.
Installed DOS 6.22 and configured the Media Vision PAS16 sound card.
Sound good and plays games great.

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Reply 13 of 19, by Intel486dx33

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And it plays Doom too.

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Reply 14 of 19, by SirNickity

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Just curious -- does your BIOS allow for >540MB HDDs? I'm wondering because IIRC mine reports "LC II BIOS Rel. 1.00", while yours is 2.00 and shipped with a HDD right at the barrier. ...which suggests they might have been thinking forward to the next model with >540MB drives, and could have lifted that 1024-cylinder barrier in Rel. 2.00. I haven't been able to find a BIOS image download anywhere (this was still when you would physically swap the flash chip though), although I had been searching for Advantage BIOS images, not Bravo. I'm fairly certain they'll be the same code.

Reply 15 of 19, by Intel486dx33

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SirNickity wrote on 2020-01-16, 19:54:

Just curious -- does your BIOS allow for >540MB HDDs? I'm wondering because IIRC mine reports "LC II BIOS Rel. 1.00", while yours is 2.00 and shipped with a HDD right at the barrier. ...which suggests they might have been thinking forward to the next model with >540MB drives, and could have lifted that 1024-cylinder barrier in Rel. 2.00. I haven't been able to find a BIOS image download anywhere (this was still when you would physically swap the flash chip though), although I had been searching for Advantage BIOS images, not Bravo. I'm fairly certain they'll be the same code.

The bios did limited the capacity of the hard drive to 400mb.

Reply 16 of 19, by Intel486dx33

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I can’t believe AST only put 8kb of motherboard cache in this computer and sold it as a Multimedia computer.
1993 was a strange time in the Multimedia computer market where computer builders were pushing the capabilities of the computer with absolute minimum hardware specs and asking $3,000 for these computers.

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Reply 17 of 19, by Intel486dx33

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I think the IBM Ps/1 had more to offer than this AST Bravo. And the PS/1 had better build quality, performance and bios. Also easy to repair and upgrade with non proprietary components.
The IBM PS/1 sold for about $2,800 back in 1993
Just add a sound card, cdrom, modem, and network card and 4mb of memory more.
Which would have put the price over $3,500

Also the Apple Macintosh color classic which sold for about $1080 back in 1993
Was a nice all-in-one computer which came with a color monitor and keyboard and mouse.
If you add a network card, 4mb more ram and speakers you could have a nice internet capable computer back in 1993.

So I think the Macintosh would have been the best value purchase in 1993.
My original Macintosh color classic with 16mhz CPU can still go on the internet today
Using a network card and Netscape 3x
Can download games and apps from internet.

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Reply 19 of 19, by Intel486dx33

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pentiumspeed wrote on 2021-04-29, 21:04:

8K is internal 486 cache.

Cheers,

Yes, I believe the motherboard actually has 16kb. Of onboard cache.
Also you needed to purchase a monitor separately on a PC where it was included on the Mac.