Bull Micral 45 - revival

[fneck]

After opening the power supply, the responsible is quickly identified, as often it is the anti-parasitic capacitor.

This time the effect is very visual, like a flower that has just opened :






OK, it works again

Wow. Did you hear any beeps?

At power up there are :
- 2 beeps at the begining of base memory countdown
- 2 beeps at the begining of extented memory countdown
- 1 beep at the boot sequence

By the way, could you take a photo of PSU'S connector?

I did not do it, I'll do it tomorrow...

[Lenord]

Nice flower) Replacement caps look enough ancient.
One time I blew the Ni-Mh battery on 486 board, it was a loud detonation, most of corrosive contents was sprinkled onto the board and i had to take everything apart(

At power up there are :
- 2 beeps at the begining of base memory countdown
- 2 beeps at the begining of extented memory countdown
- 1 beep at the boot sequence

I did not do it, I'll do it tomorrow...

Thanks. Could you also temporarily disconnect your MFM board and try booting without it?

It seems that my oldest videocard fits best, at least I hear first 2 beeps, but then something happens.

2 short beeps just upon start
1 beep at 5s
3-4 short beeps at 20s
1 beep at ~37s

There were problems with ISA VGA cards on XT machines, but 286 may also don't like some v-cards. I will try to get something old enough.
As far as i know, any ISA riser will fit because each ISA slot there is connected in parrallel way, so there shouldn't be any problems from that side.

[fneck]

Hi, here is the power supply connector :



I did three tests this morning.

First, I disconnected my MFM card and the computer boot normally on the floppy drive.

Secondly, with a VGA card on a 16 bits slot. What I observed is quite curious, because at first I thought nothing was happening but after 30 seconds the floppy started to spin. On the other hand, there was no beep or no display on both screens (VGA and EGA). The computer seemed to boot without any display. Without having the correspondence of the swithes of the motherboard, it will be complicated to operate in VGA because it would be necessary to inhibit the internal graphics card.

Thirdly, I tried the setup floppy that you mentioned in a message above. It works perfectly in English but not in French because of a corrupted file. It's a text file, I'll see if I can do anything to fix it.








Now, if I want to continue I must think about the battery so I can save the configuration.

[fneck]

Regarding the backup battery, it is a 7.2V non-rechargeable lithium. It consists of two 3.6V AA-type elements and a 47 kohm resistor in series.

And the positive polarity is on the white wire, so contrary to what was said above on pin 2 of P14.

[Lenord]

Ok, seems that my combination is true and the color coding of those wires complies with AT standard.
My guess about the MFM card has also been confirmed, thank you.
I think, riser card couldn't be a problem too so any other (without PCI) riser will work fine. Moreover, videocard itself should work fine there.

Earlier this day i borrowed one more ISA videocard from my friend.
This card is Morse KP 800/16 VGA and works fine in his 286 PC (but it has no built-in graphics unlike this BM).
It has 256kb of VRAM and two video outputs - VGA and EGA (MDA/CGA...other types can be emulated there).
By the way, he has its original manual with all configuration, I am going to scan it and add somewhere.

Even this card doesn't show anything. And yes, 2 of 3 ISA16 cards and this new card cause same symptoms.

Secondly, with a VGA card on a 16 bits slot. What I observed is quite curious, because at first I thought nothing was happening but after 30 seconds the floppy started to spin. On the other hand, there was no beep or no display on both screens (VGA and EGA). The computer seemed to boot without any display. Without having the correspondence of the swithes of the motherboard, it will be complicated to operate in VGA because it would be necessary to inhibit the internal graphics card.

No beeps during startup, but keyboard works and if i press a lot of keys, there will be beeps. I've also connected a floppy drive (i have only 1.44Mb), after some time it starts to check it (like with "boot up floppy seek" bios option enabled) but then it starts booting too!
I've inserted a diskette with some simple DOS and it really tried to load it.

It's very useful that you've tested that both EGA and VGA outputs don't show anything in this case.

I think you're right, internal and external adapters are interfering with each other in strange way.
There must be a way to turn internal graphics off. It could be hard to guess without any manual(

There are 3 jumpers nearby - JD01, J1, J2. Try to change JD01 and/or add J1 with VGA card installed.
I've already tried but without any success( Removal of J2 blocks startup.
I tried to remove the whole PARADISE chip, then in one position of JD01 i got just new beeps, but another position gave normal start.
But there should be something else, because i am not getting any picture in any position(

What do the jumpers on 286 usually do?

Thirdly, I tried the setup floppy that you mentioned in a message above. It works perfectly in English but not in French because of a corrupted file. It's a text file, I'll see if I can do anything to fix it.

Nice to see that this disk image is compatible with BM model 45, too.
I hope it will work, that guy also said that image could be corrupted.

Concerning battery, It seems that they are not rechargeable ER14505. I thought that they were not AA, but something bigger.
Bearing in mind that lithium doesn't like direct soldering, best solution is to get 2xAA holder and insert new ER14505 batteries there.

And the positive polarity is on the white wire, so contrary to what was said above on pin 2 of P14.

Yes, also have to say that pin2 has ~+0.8v when the board is working.

And i've found out an interesting peculiarity - this board has exactly 8 layers. There is a small transparent window and each layer is numbered. I will try to take a photo tomorrow.

[fneck]

I think you're right, internal and external adapters are interfering with each other in strange way.
There must be a way to turn internal graphics off.

This is normal because the ROM of the two cards is located at the same address.

[Lenord]

This is normal because the ROM of the two cards is located at the same address.

That JD01 may change MONO/COLOR output modes and therefore affect ROM addressation. That was my hope.
Maybe it's not enough.

[Lenord]

GOT a picture via VGA!
Nothing to do with jumpers, i've turned on all switches of first block (SW1).
There was only one enabled by default.

Specific switch which makes this working is №5 in SW1 part.

It tests only base 640k, then i see 3 errors (checksum, memory size and configuration errors) which cause 3 beeps, then some DOS loads fine from my 1.44Mb drive.


By the way - it seems that i have later v2.0 BIOS revision than yours v1.2c.
I will try to find somebody with flasher to dump an image of both BIOS parts.

[fneck]

God job Lenord, it works as well for me

So switch 1-5 to ON to disable the internal video card. I still have both connected but the EGA no longer displays anything.


I took the opportunity to install an XT-IDE card to replace the MFM hard drive and it works perfectly, without even changing the BIOS configuration.


I intend to use again the hard disk MFM but before I wait to have the backup battery. I ordered the batteries to redo the pack.

[Lenord]

So switch 1-5 to ON to disable the internal video card. I still have both connected but the EGA no longer displays anything.

Yes, just one switch, #5 in SW1 block allows to get a picture via VGA.
I don't think that it's possible to use 2 videocards at the same time, so it's ok that EGA is not working.
So, your VGA OAK works fine now, that's nice.

I still can't boot with its configuration floppy like you did, that stucks when booting.
Maybe that's because of 3.5" 1.44Mb floppy drive and diskette i use?

I took the opportunity to install an XT-IDE card to replace the MFM hard drive and it works perfectly, without even changing the BIOS configuration.

Great news, i hope if I find some multicontroller for ISA bus, it will be recognised too.
But before doing that, I have to find an ISA riser.
Maybe it is possible to boot from the built-in SCSI port too.

I am also unsure what is onboard "IDE", maybe that could be transformed into normal one.

Is there a way to save bios image from DOS?

[fneck]

Maybe it is possible to boot from the built-in SCSI port too.

I do not think so. In general a bootable card requires a ROM, or nothing is seen during boot.

Is there a way to save bios image from DOS?

Yes, with the DEBUG command but I could not give you the exact syntax.

[Lenord]

I do not think so. In general a bootable card requires a ROM, or nothing is seen during boot.

Ok, it's really strange that they've put SCSI onboard. Maybe that's for future devices like CD-ROMs and ZIP drives.

I hope i will cope with DEBUG syntax. Since BIOS has two parts, I don't know what i should expect.

I've understood what caused my problem with configuration floppy.
I had to convert this 5.25" 360kb floppy image to 3.5" 1.4Mb one with a help of WinImage.
So now everything works ok and i am also looking for battery replacement.

Used Modbin to dump some data, seems that it contains BIOS.
https://drive.google.com/file/d/1M2_ex2 ... sp=sharing
https://drive.google.com/file/d/14R8qIh ... sp=sharing

[fneck]

For the battery, I put some information here:
viewtopic.php?f=27&t=9780

Regarding the setup program, I repaired the French message file and re-created a floppy image disk in 360 and 720 KB, available here:
https://software.system-cfg.com/bios/bull/

[fneck]

Used Modbin to dump some data, seems that it contains BIOS.

This seem to be the EGA card ROM, not the BIOS.

[edit] No, you're right, in fact it may be the 64 KB ROM.
I cannot extract it with DEBUG but the beginning of what I see on the screen is the same.

[Lenord]

Great work, looks genuine)
I am also going to re-create the battery but i have to take some parts from a local store.
It's hard to find those batteries nearby, maybe I will use 18650 rechargeables and another resistor for that.

Thank you for correct floppy image! I will test it later.

No, you're right, in fact it may be the 64 KB ROM.
I cannot extract it with DEBUG but the beginning of what I see on the screen is the same.

Yes, there was something concerning Paradise EGA at the beginning, therefore i am not sure that it's pure BIOS.
Maybe some shadowing is still active but we can't turn it off.

I will try to change other switches and find their meanings.

It shows that you have 3072k of external RAM, but how much of it have you installed? 4x1Mb?
I've installed 6Mb but can't properly configure them. I am not sure that my board uses more than 640k since it's not shown anywhere.