386 box supertunning

[electronixguy]

jlf65

Looks like an interesting board you have there. As for your "older" laptops - they're newer then the one I use every day (P2/400 MHz w/128 RAM & 20GB HDD)!

I've seen ads like that in the local buy & sell paper, I always get a good chuckle when I see "Great desktop computer! Monitor, keyboard, mouse, epson printer. 486 - 66 w/32MB RAM. $1000 obo" (that's actually an ad I just saw yesterday in the marketeer, I called and it wasn't a mistake on the price... ). The worst ones are those who don't say what the system is, and hope you won't ask...

Cheers,
-Bill

[electronixguy]

Apr 3, 2009 14:49:07 GMT -5 Tom Maneiro said:

electronixguy: Sorry about your Siemens laptop... finding service manuals for these things are hellish hard these days (if they exist at all). Have you done a deep check of the motherboard? Look for shorts, asploded capacitors, dead batteries and some misc failures... When i first had my 386, the thing refused to boot from the harddrive (a old Conner CP30084A)... until i whacked the drive several times. (BTW: that Conner drive recently died, but lasted a looong time....)

Have you considered to try MenuetOS there? I tried a long time ago... and it was an EPIC FAIL AROS? Sounds interesting... Let's save this one for another torture testing once i manage to fix that Dallas mess

Yeah, I gave it a good looking over, and it seems that someone either powered it up wet, or reversed to polarity of the power connection. I'll try to get it running again when I have more spare time to spend on it - I don't give up easily.

As for MinuetOS, I'll have to take a look at it, as I don't really remember it...

Cheers,
-Bill

[electronixguy]

Just a little update for anyone who cares...

I've put most of my projects on hold for a while, as I just got married

I will resume them as time allows in the near future. I haven't had the time to do any research on MinuetOS yet, as I had more things to plan then I expected. If anyone is interested, I will be setting up a web page with photos and such, I'll likely post a link in my next post with the signature line or something.

Anyhow, have fun.
-Bill

[jlf65]

Congratulations! Or should it be condolences?

[electronixguy]

@ljf65

Thanks. I'd consider it a "congratulations" moment, rather then a "condolences" one... It went very well.

The link in my signature line leads to a simple page hidden in my main site with a few photos and the text of the ceremony, if anyone wishes to take a look.

Have fun,
-Bill

[jlf65]

From the pictures, it seems like you had an outdoor ceremony. At least the weather looked nice. A spring outdoor ceremony is very popular with a lot of people. Anyway, it looked like a nice little wedding, and I wish you and yours much happiness. I come from a fairly big family, so I've been to quite a few family weddings. Weddings are always nice. A very joyous occasion.

[electronixguy]

ok, I've started on a few projects again now... got a commodore 1802 color monitor to repair at the moment, then I'll try my luck with the Siemens laptop again.

jlf65
Actually, it was an indoor ceremony, but it was a Mormon church (no photos allowed in the chapel), so most of the pictures are outside.

@tom
Looking into MinuetOS now, might try it if it looks functional. We'll see what happens.

Anyhow, take care.
-Bill

[Tom Maneiro]

Nice experiment, good stash... I wish you luck

Back to me... i'm on the final year of my career (doing my last internship before ending five years of torture), so i have next to no free time for now... This is a major block for all of my experiments, and also for finding someone able to repair my fuxored DS1287 board

HOWEVER, not all hope is lost - i found someone willing to perform the repair! It's the same guy from the lab at the university where i used to get all my trash cool stuff. If everything goes well, this Monday the board should be back to regular service... now let's hope for the best.

In the meanwhile, PHOTO TIME! (now with more cameraphones... i just added a Motorola K1m to the collection, and while having the same camera chip as my other RAZR, it seems to have a less-sucky lens, so enjoy some good pictures this time)

- Total Marika teardown (i will send the motherboard to the workshop, not the entire box!)


- The motherboard has this funky PCB rework at the back... a couple of old-fashioned resistors here and there bridging some points, and this freakishy green wire running from one of the FPU socket pins to one of the resistors placed near the RAM slots....


In one word: Why?

- Core view 1

Clockwise, starting at the "IIT" chip:
- IIT 3C87 FPU, exclusive import from ye olde England
- EVIL DS1287/1187, DEAD AND SOLDERED, EVIL! Did i said that this is EVIL? This one was made in early 1993, so its battery lasted 16 years... Not bad.
- BIOS ROM EPROM, 64K. EPROMs sucks, but you're protected aganist nasty flashROM viruses
- AuthenticAMD(tm) Am386SX/SXL-33. Look Ma', no stinkin' NASA heatsink/fancooler!
- Part of the onboard 2MB integrated RAM

- Core view 2

Integrated OAK OTI-077 SVGA video. It comes from factory with 256K of VRAM, but i've maxed out mine with a whooping 1MB of VRAM, allowing me to do something like 256 colors at 1024x768. Hardly HD, but that's already too much for a 386

- Core view 3

ALi M1409A chipset (IDE+), M1505 IO chip?

This motherboard looks rather compact for a 386 with everything integrated... until we remind that this sucker was built in 1993, when the 386 was a mature platform (read: obsolete). Also it lacks expansion slots - they're packed in a separate riser card.


SPARES! Our lab is full of surprises, including this stack of unused DIP-24 sockets, perfect for our DS1287 and clones:


Testing the socket in a socket:


FYI: teh Houston Tech HT12888 clone is nothing more than:
- HT12888A: a VIA VT82885N with a fancy shell (no epoxy, no battery, no nada)
- HT12888B: a glorified battery holder with a fancy shell, quite dangerous to remove as you may end ripping the entire battery holder from the PCB



Now for more random goodies... (man, i really miss those hacking days at the lab... nothing beats the smell of fried PCCHIPS boards on the morning )

- R@RE, L@@k, COAST cache modules (non-fake cache):



- Assorted motherboards: a couple of socket-7, Slot-1, and a dead LGA775:


- RAMs, old CPUs (Decelerons, Pentiums and 486s):


- Rails full of old ICs...


The yellowish rail contains 7493A's (no LS, no HC, just original-flavor TTL)
The other tube contains some NEC 8255's, ideal if you need a new parport driver for your vintage IBM Personal Computer(tm)

- You know that you have a GOOD floppy drive in your hands when the sucker has JUMPERS with unknown purposes...

(Incidentally, this was my old Mitsumi 5.25" drive, now bricked)

- Conner HD gold:


- Fat: CP30104H (104MB, early 1993, status unknown)
- Baby: CP2044PK (44MB, late 1991!, status: it was live one or two years ago)

- The "Papa Conner and Baby Conner"



And as the final shot, the Stupid Shot of the Day...
- Mr Blurrycam(tm) presents: Watanuki Kimihiro's choice: the original Deceleron!

(you will wish always for SOMETHING ELSE, even a 486, if you're on one of those. Be careful to not end as a slave for Intel, though )

See ya later, hopefully with a fully working 386 box again...

[Tom Maneiro]

While cleaning up a bit the motherboard, i've noticed a few interesting things:

- This board has the option to use either a DS1285 or a DS1287. This is because i've noticed spots for a battery input pinheader and a crystal/oscillator near the DS1287 spot. Following the traces in the PCB, indeed, you theoretically can get rid of the DS1287 pain, add a plain DS1285 (or maybe a clone like a VT82885N), add a crystal, a battery, and presto! No more pesky module replacement... But which crystal should i use there? Time to read those datasheets...
EDIT: Datasheet sez:

Connections for Standard 32.768kHz Quartz Crystal. The internal oscillator
circuitry is designed for operation with a crystal having a 6pF specified load
capacitance (CL). Pin X1 is the input to the oscillator and can optionally be
connected to an external 32.768kHz oscillator. The output of the internal oscillator,
pin X2, is floated if an external oscillator is connected to pin X1.

- Remember that freakishy green wire in the back of the motherboard? After close inspection, this is connected to one of the pins of the 66MHz oscillator (the CPU clock generator), through a 330 ohm resistor (+/- 5%), to one of the 387SX pins... Maybe an alternate clock source? There is also a 2.2K resistor bridging two pins of one of the SIMM module slots... maybe related to the onboard RAM or something? I'm also thinking into doing the overclocking thingy... but i need to get a socket for my 80MHz crystals (or gut some bigger one to make a "kustom" socket )
EDIT: I can easily make a "kustom socket" by chopping one of those DIP-24 sockets, into a weird, long "DIP-8" 40MHz 'SX, here we go!

[oompa loompa]

you shouldn't have a problem with obtaining a 32.768khz crystal . each crystal has different capacitances, but i think for this, your okay with using any crystal you can find (it just affects the stability, which i don't think doesn't matter ). the crystals can be found everywhere that keeps track of time, eg: digital wrist watches, clocks, other motherboards, etc. the crystal just looks like a small shiny round tin-can.

eg: courageous.murch-sitaker.org/%7Ekragen/electronics/littlewatch/disassembled-side.jpg

and then check if there are any other connections from the battery traces on the board. most motherboards will shoot 4-5v into the battery to charge it while the computer is powered on. if you're using plain old alkaline batteries, then you don't want this. check if there's a place to put a diode, or if there is none, then i would put a diode in between the battery and rtc, just to be safe. if you use rechargeable lithium (not the coin type), then no worries there

the 2.2k resistor is for the RAS signal i think, for small SIMMs

[Tom Maneiro]

The motherboard sucessfully arrived to the "service lab"

Stay tuned... Next, on TSDX Films(tm): Marika, 2Fast, 2Furious 40MHz is the next stage... see ya there!

[electronixguy]

@tom

I hope all works out well with your board, I look forward to your next update. Looks like quite an assortment of parts that you have listed above, many experiments in potential, to be sure.

I'm happy to say that I will soon be receiving a Zeos 386 laptop from a friend, so now I'm open for ideas as to what I should do with it. I'm not sure on the specs of this machine, so I have no clue as to the RAM or HDD size, or the CPU speed... We'll just guess it's a 386sx 20 with 4MB RAM and an 80MB HDD

Currently trying to network a 486DX 33 (Compaq Presario CDS 524) that I have here, it's not easy to locate ISA ethernet cards around here. Hopefully I'll get it working when I get the chance this weekend.

Cheers,
-Bill

[electronixguy]

HI EVERYBODY!

Well, the compaq was a success. I'm using it now to post this message. Config is as followes:

Model: Presario CDS524
Processor: 80486DX-33
RAM: 12MB
HDD: 400MB
OS: Windows 95 A
Browser: Internet Explorer 5.5
Connection: direct via parallel (all my ISA NICs are dead, after much aggrivation...)
Removable media: 1.44MB floppy, 48X CD-ROM (the original one finally quit)
Input: Cirque "Wave Keyboard" with built-in trackpad
Display: built-in 14 inch CRT, 800x600 @ 256

Well, at least I know it will work now. Connected to laptop running XP, bridged LPT connection to WiFi, downloaded netscape 4.8 from oldversion.com (using IE 3), now decided Netscape is far too slow and am using IE 5.5

This reminds me of the dialup era, connection speeds suck! Hopefully a friend can locate a working ISA NIC for this thing in the near future. I'll try to do some photos of this insane configuration within the next few days.

Anyhow, everyone take care
-Bill

[electronixguy]

Hello again,

using an old thinkpad 310ED now, with Corel Linux Deluxe 1 installed (Netscape 4.7 browser).
At least this one has a proper network connection via PCMCIA (10 MBPS, Megahertz Xjack thing).
Page formatting sucks, netscape crashes on certain sites, but it seems to work about 80% of the time.

On another note,
is this board still active? Haven't seen any new posts in a while, was it something I said??

Take care,
-Bill

[oompa loompa]

i use to be able to browse these forums using a 486 33mhz laptop running windows 3.11, and some early version of netscape.

there are people that still browse these boards. a lot of people dissapear for a while, and then come back though . i pretty much visit everyday just to remove spam from the forums, but most of the time i don't have the time to post messages