Topic: PC-35III Various questions

[rrete]

Hi!
I've got an old 80286 PC-35 III with PC-40III motherboard, last acquisition for my collection. After a good cosmetically update because was forgotten in a garage near the sea for years!!!!!!!! Fixed DALLAS RTC 1287. boot properly but I find several problems. Nothing found on the net about it (no manual, motherboard information...)

1.- HD was totally dead, swap with other similar.
2.- It had an unidentified 3 1/2 FDD that don`t work, put a Chinon FZ-354 (1.44)  instead, and an Epson 5 1/4 HD for the second bay.

Now:
One problem: new hd had no OS so system must boot from floppy, when system access to floppies a curious and never seen "thing" shows. One unit lit and other unit spins motor, no in the same unit (which is the correct behaviour) then "Boot failure", Change configuration in bios, swap units A-B, B-A, tried data cable with turn at end and without it, no results. ¿? There are several jumpers two near FDD Bus and other in the IDE bus, function of those? maybe one solves this...

Second: bios has a few HD types with no user type (hard to find if HD dead), can use an ISA HDD/Floppy controller to use bigger HDs?

I hope somebody can help me.

Thanks for read,

[Blacklord]

The PC40 (in Australia at least) was a 286 with a small form factor board and built in VGA. The series III (again, at least here) was a redesigned version that fixed a few issues in the 1st and 2nd version (more than 1mb memory for example). IIRC it ran at 12MHz (switchable).


If you've got a floppy staying on, then that usually would indicate the floppy is likely cabled incorrectly or jumpered incorrectly - have a hunt around for Total Hardware 99 and try to ID the floppy drives you have and set them up accordingly. Also try with just one drive at a time until you know they are both working.


TH99 may also have the PC40-III mobo too, but I can't really be sure. Commodore tended to be very standard with their PCs (they used generic rebranded ones) so you may well be able to find thec same mobo from another manufacturer and get the jumper settings from that.


Those jumpers you have near the drive cables on the mobo are for enabling/disabling the onboard controllers - so yes, you can use another ISA card.

[ruud]

One unit lit and other unit spins motor, no in the same unit ....

I have only working with the XTs lately and they show the same problem when using drives from IBM (clone)s. This is due to fact that DS0 is used instead of DS1 and one line is used in another way. What and how exactly I don't know yet. I only found out by accident last weekend. I found another 3.5"" drive that I wanted to install in my PC20-III. But it didn't work correctly. Weird enough it did work in a real IBM. Only then I noticed two differences on the little PCB that converts the flat edge connecter to the 34 pins header connector:
- the already mentioned DS1
- a small wire soldered on another place then on the PCB of the C= drive.
At this moment I haven't access to both drives so I cannot check further.

Regarding the HDDs: you can always attach a modern big drive but the PC will treat as the one you choosed in the setup. It worked for me.
Another  solution I want to work on is changing the harddisk table: change some of the entries to the values of more modern HDDs. But I forsee a bear on the road: it's possible that the BIOS is limited to 512 MB.
And even then there is a solution: in another I mentioned the Universal BIOS http://code.google.com/p/xtideuniversalbios/ for the XT-IDE card. It also supports 16-bit IDE interface as used by the AT. Find a Network card with an empty BootROM socket and use that for the EPROM. I have seen messages on other forums that this seems to work. One remark: before burning an EPROM make sure you set the program to use the 16-bits interface.

[ruud]

Those jumpers you have near the drive cables on the mobo are for enabling/disabling the onboard controllers - so yes, you can use another ISA card.

Could you be more precise, please: what jumper does what?

Do have information on other jumpers as well? Including the XT boards?

Many thanks !!!

[Blacklord]

Those jumpers you have near the drive cables on the mobo are for enabling/disabling the onboard controllers - so yes, you can use another ISA card.

Could you be more precise, please: what jumper does what?

Do have information on other jumpers as well? Including the XT boards?

Many thanks !!!

The very earliest (PC5 & PC10) use exactly the same jumper settings as an IBM XT. The later ones are different - I do have these, but on another PC so I'll need to dig them out.

[uridium]

G'day,

I've got a PC40-III here I've been trying to get up and running that arrived in the post yesterday (yay fleabay etc). Wanted one of these for years. Okay, Went bug-nuts at the dallas RTC with the dremel and soldering iron and that's all working. Now I can't get it to boot from floppy. I get even when using the original chinnon disk (FB-3571) and other drives "Floppy 0 configuration error", or nothing and no boot. During the POST it seeks the floppy head (can hear it), spins up the motor, then goes to load the OS. Heads move and motor doesn't spin. Noyce. Not sure what's going on there.

Btw.. some confusion over the "adapter board" on the floppy drive. Tracing the signals, these merstly just replace the twist in the cable. I have the manuals for the thing and it tells you to cut the R-D 7 select if you have a second drive on the floppy lead before the FB-3571.

Okay, that mystery is solved. Also the disk is 720kb and not 1.44mb. This melts my brain because the floppy disks with setup utils, hard disk parking utils that CBM shipped were a mix of 720kb disks DSDD with only the R/W hole, and the other two were DSHD's with the hole. Here's the fun bit.. if you examine the disk contents, *ALL* of the disks are 1.44mb DSHD and there's data on them. So.. this drive can't read them? *Shifty eyes* Riiiiight moving along because I have NFI.

I've tried about 20 floppy drives with the machine and different cables (with twist, without, with the FB-3571) ..no love.

Okay. Anyone have a clue as to what the other jumpers on the mobo do? The manual talks about jumpers for the IDE disk only, for the record:

JMP 903 and JMP 904

Jumper/Function/default/Result
903/Disable HDD/Not Installed/HD Enabled
904/HD Type/Location B/Quantum HD

They talk about different supported disk types in the manual, given that half of these drives when you look up their ATA spec compliance is all over the place, I'd take these two jumpers as Off/On and "other" mode.

So.. anyone know how to disable the floppy drive controller? I'd like to try an adaptec AHA1542 in there for two reasons, one .. it might work (!) and secondly because it's buffered (Much much faster for writes and reads) and has a z80 to do the IO grunt via DMA. I used to use one on an older Commodore PC10 and it was pretty happy.

So.. other jumpers guys? Any ideas?

Thanks in advance.

Regards,
Al

[rrete]

HI!

Thanks for repplies!
In the TH99 no information for the PC40-III MB is, only for a MB for 286 but with 30 pin sockets for extra ram, that isn't the model. NO similar model in other bran found 
I see that the floppy "problem" is know for somebody more. Y think probably come from the floppies, the one I've put is a spare from
my Amiga collection and that had tested on A4000 and in a old Goldstar 80286 PC working fine. I put this model because is the model that came in factory setup ( www.amiga-stuff.com).  I've tried change floppy disk 0 to DS0 like Amiga floppies, thinking PC35 uses C=1352 mouse (Amiga mouse) so why don`t the floppies uses the same configuration?... No results

About ISA HD controller that's right only can use pre-defined models of the bios, there are no user model, this week I'll try to boot from a SCSI HD with a controller for it???     I'll report results.

Jumpers:

mine are like this:
X--X (Closed)
X  X (Open)


X--X  X       :::::::::::::::.:      (floppy conn)
X  X

and

         X--X
:::::::::::::::::::: (IDE conn)

function?

thanks again

[rrete]

Is possible flash C= PC bios?
And with XTIDEBIOS??

I've found "drivepro"..What about it? Somebody know it?