Vintage Sirius Computer - UK Vintage Radio Repair and Restoration Discussion Forum

Cobaltblue · 10th May 2025, 8:49 pm

My 80's Sirius is emerging over the last two weeks I have separately found the monitor, PC and Keyboard of course I didn't think to take pictures not expecting to see the other parts

Picture will follow in a few days but I'm away from home right now.

What I have located so far looks pretty much like the system in the picture attached.

What I haven't found (so far) is a mouse or a Pad as its been boxed up for 30+ years anyone know what I should be looking for ?

Cheers

Mike t

Keith956 · 10th May 2025, 9:11 pm

Wasn't the Sirius the precursor to the Apricot? I had the latter in the mid 80's. It didn't have a mouse, just a keyboard. Did the Sirius have one?

Cobaltblue · 10th May 2025, 9:32 pm

I must admit I thought the Apricot was early 80's (Apple II Clone) this looks more like PC clone so Mid 80's

Still haven't found my Apple II but there are still a lot of boxes

Cheers

Mike T

TonyDuell · 11th May 2025, 5:37 am

The Sirius (known as a Victor 9000 in the States) is a strange machine. It uses an 8088 processor, but, (not surprising given the history) the floppy disk system is very similar to the Commodore ones, GCR encoding and all. The disk drive spindle motors are variable speed too

It's also stuffed with 6522 VIAs, I think there are 3 on the motherboard and 3 on the disk controller.

I seem to remember the video system is similar to the Apricot (which has nothing to do with the Apple ][). Character codes from the video memory are effectively pointers to the character generator table in main RAM. And the caracter code is something like 11 bits wide so each screen location can be a differerent character with its own bit patten so you get high resolution graphics that way.

I think there are schematics, etc of the Sirius on bitsavers

dglcomp · 11th May 2025, 11:29 am

It's an MS-DOS compatible machine (importantly not an IBM compatible), someone on YouTube has recently done a series of videos on the Apricot/Sirius machines,
https://youtu.be/A93TmmF3Q3w

paulsherwin · 11th May 2025, 11:51 am

Neither the Sirius or Apricot were IBM compatible and they never ran any version of Windows, though ACT/Apricot did manage to get a version running on the later still-incompatible Xen. The Sirius was 1982 and the Apricot 1985. You could use a mouse with them, but that wasn't the standard way of interacting with most software and most examples didn't have one.

They were well regarded and had strong LAN support (by mid 80s standards).

Cobaltblue · 11th May 2025, 12:26 pm

Thanks for the information so far I am sure it never had a mouse but a sort of wand, which I have not come across so far.

I got it when it was scrapped by the company in the early 90s where it was used for CAD. I dont think I used it much as I spent the next 15 years or so working overseas by which time it was an antique in computing terms.

Thanks for the info about apricot as well. Things I had completely forgotten.

Cheers
Mike T

TonyDuell · 11th May 2025, 12:40 pm

The Sirius has a very nice user port on a 50 pin header on the motherboard. It's an entire 6522 (the only port line used elsewhere is PB7 which is a clock for the sound circuitry) and a lightpen input. The latter goes to the 6845 CRT controller chip as you might expect.

My guess is the 'wand' was the lightpen. You touch it on the screen, it detects the flash of light as the beam scans that area. The CRT controller then latches the video address which can be read by the processor to determine what you are pointing at.

Another interesting bit of the Sirius is the sound circuitry which was a lot better than the 'beep' from other machines of the time. It consists of an 6852 synchronous serial chip linked to a CODEC. In the standard machine only the 'output' direction is used, but there's another header on the motherboard for audio input.

The Apricot and the Sirius are quite different machines. The Sirius has this strange GCR variable speed floppy disk system, the Apricot has a standard MFM disk controller IC with normal Sony (600rpm) floppy drives. The Apricot is also one of the few machines I've come across to use the Intel 8089 I/O coprocessor (a fancy DMA controller add-on for the 8086/8088)

Cobaltblue · 17th May 2025, 2:57 pm

The Lightpen operation is pretty much as you described Tony.

I remember Jill who did all our CAD work for the department using both a light pen or wand as she referred to it but also a tablet which was around A3 size it also used a pen but not the same as used on the screen.

I think that one had a magnetic tip, but it was over 30 years ago

I'm also pretty certain I never had the Tablet as it was used on a newer machine, may have been a Sun Microsystems machine as we used those extensively after moving away from The VAX machines.

Anyway all 3 parts already seen put in one place and for sure its grubby.

No chance to power it for at least a week but I'm pretty certain the monitor has a fault as the cover screws are missing.

Its still in the loft it needs to move to a bench.

Cheers

Mike T

TonyDuell · 17th May 2025, 3:21 pm

The tablet sounds like a magnetostrictive thing, probably made by Summagraphics. There were several models, some with RS232 or GPIB interfaces that could have been linked to the Sirius. I'll not go into the theory or repair of those here as you don't have it. (I am happy to answer questions on them, I've repaired a few and designed the control electronics for one).

Apart from the fact that brightness is controlled by a 3-bit DAC on the motherboard, which results in the CRT grid bias apperaring on the monitor connector (!), the monitor is conventional. There's a uPC1031H2 for the vertical deflection, a discrete transstor horizontal deflection circuit (2 transistor as a monostable, then line driver transformer coupled to the line output transistor). EHT and other voltages>12V come from the flyback transformer as usual.

Cobaltblue · 30th May 2025, 8:37 pm

I finally got the Sirius onto my temporary bench, these things seem to get heavier as I get older!

Work and the needs of the family give me little spare time sadly.

I don't like powering SMPS via lamp limiters or variacs so I gave it full mains.

The LED on the front came on no attempt to power the disc drive and after a couple of minutes a lot of smoke and a big bang actually two big bangs.

So I pulled it apart and found pretty much what I expected.

I have replaced these with modern parts but after trying again no activity from the monitor or disc drive no drama either.

Time to check the supply rails

Cheers

Mike T

ortek_service · 30th May 2025, 11:52 pm

The dreaded RIFA's strike again (well after a delayed time, whilst they are getting hot, until smoking a lot.)

And whilst the ones in the AC mains filter shouldn't stop the PSU from working, I can see at least one-more clear-epoxy RIFA that may be in other areas of the circuitry. So wonder if you've changed all the rest of these, even if they haven't burnt-up yet? (although they've no-doubt had their epoxy failed with cracks in it).
I have recently had a PSU where a burning-up RIFA had stopped it working, but replacing them all inc. DC-only rated ones had fixed it.

Although if you are getting a Power LED, it seems the PSU is probably running OK and there's problems elsewhere.

10th May 2025, 8:49 pm	#1
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 7,745	Vintage Sirius Computer My 80's Sirius is emerging over the last two weeks I have separately found the monitor, PC and Keyboard of course I didn't think to take pictures not expecting to see the other parts Picture will follow in a few days but I'm away from home right now. What I have located so far looks pretty much like the system in the picture attached. What I haven't found (so far) is a mouse or a Pad as its been boxed up for 30+ years anyone know what I should be looking for ? Cheers Mike t Attached Thumbnails __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk

10th May 2025, 9:11 pm	#2
Keith956 Heptode Join Date: Jun 2019 Location: Oxfordshire, UK. Posts: 990	Re: Vintage Sirius Computer Wasn't the Sirius the precursor to the Apricot? I had the latter in the mid 80's. It didn't have a mouse, just a keyboard. Did the Sirius have one? __________________ Keith www.peardrop.co.uk

10th May 2025, 9:32 pm	#3
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 7,745	Re: Vintage Sirius Computer I must admit I thought the Apricot was early 80's (Apple II Clone) this looks more like PC clone so Mid 80's Still haven't found my Apple II but there are still a lot of boxes Cheers Mike T __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk

11th May 2025, 5:37 am	#4
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 6,087	Re: Vintage Sirius Computer The Sirius (known as a Victor 9000 in the States) is a strange machine. It uses an 8088 processor, but, (not surprising given the history) the floppy disk system is very similar to the Commodore ones, GCR encoding and all. The disk drive spindle motors are variable speed too It's also stuffed with 6522 VIAs, I think there are 3 on the motherboard and 3 on the disk controller. I seem to remember the video system is similar to the Apricot (which has nothing to do with the Apple ][). Character codes from the video memory are effectively pointers to the character generator table in main RAM. And the caracter code is something like 11 bits wide so each screen location can be a differerent character with its own bit patten so you get high resolution graphics that way. I think there are schematics, etc of the Sirius on bitsavers

11th May 2025, 11:29 am	#5
dglcomp Heptode Join Date: Jul 2016 Location: Portland, Dorset, UK. Posts: 943	Re: Vintage Sirius Computer It's an MS-DOS compatible machine (importantly not an IBM compatible), someone on YouTube has recently done a series of videos on the Apricot/Sirius machines, https://youtu.be/A93TmmF3Q3w

11th May 2025, 11:51 am	#6
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 30,516	Re: Vintage Sirius Computer Neither the Sirius or Apricot were IBM compatible and they never ran any version of Windows, though ACT/Apricot did manage to get a version running on the later still-incompatible Xen. The Sirius was 1982 and the Apricot 1985. You could use a mouse with them, but that wasn't the standard way of interacting with most software and most examples didn't have one. They were well regarded and had strong LAN support (by mid 80s standards).

11th May 2025, 12:26 pm	#7
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 7,745	Re: Vintage Sirius Computer Thanks for the information so far I am sure it never had a mouse but a sort of wand, which I have not come across so far. I got it when it was scrapped by the company in the early 90s where it was used for CAD. I dont think I used it much as I spent the next 15 years or so working overseas by which time it was an antique in computing terms. Thanks for the info about apricot as well. Things I had completely forgotten. Cheers Mike T __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk

11th May 2025, 12:40 pm	#8
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 6,087	Re: Vintage Sirius Computer The Sirius has a very nice user port on a 50 pin header on the motherboard. It's an entire 6522 (the only port line used elsewhere is PB7 which is a clock for the sound circuitry) and a lightpen input. The latter goes to the 6845 CRT controller chip as you might expect. My guess is the 'wand' was the lightpen. You touch it on the screen, it detects the flash of light as the beam scans that area. The CRT controller then latches the video address which can be read by the processor to determine what you are pointing at. Another interesting bit of the Sirius is the sound circuitry which was a lot better than the 'beep' from other machines of the time. It consists of an 6852 synchronous serial chip linked to a CODEC. In the standard machine only the 'output' direction is used, but there's another header on the motherboard for audio input. The Apricot and the Sirius are quite different machines. The Sirius has this strange GCR variable speed floppy disk system, the Apricot has a standard MFM disk controller IC with normal Sony (600rpm) floppy drives. The Apricot is also one of the few machines I've come across to use the Intel 8089 I/O coprocessor (a fancy DMA controller add-on for the 8086/8088)

17th May 2025, 2:57 pm	#9
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 7,745	Re: Vintage Sirius Computer The Lightpen operation is pretty much as you described Tony. I remember Jill who did all our CAD work for the department using both a light pen or wand as she referred to it but also a tablet which was around A3 size it also used a pen but not the same as used on the screen. I think that one had a magnetic tip, but it was over 30 years ago I'm also pretty certain I never had the Tablet as it was used on a newer machine, may have been a Sun Microsystems machine as we used those extensively after moving away from The VAX machines. Anyway all 3 parts already seen put in one place and for sure its grubby. No chance to power it for at least a week but I'm pretty certain the monitor has a fault as the cover screws are missing. Its still in the loft it needs to move to a bench. Cheers Mike T Attached Thumbnails __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk

17th May 2025, 3:21 pm	#10
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 6,087	Re: Vintage Sirius Computer The tablet sounds like a magnetostrictive thing, probably made by Summagraphics. There were several models, some with RS232 or GPIB interfaces that could have been linked to the Sirius. I'll not go into the theory or repair of those here as you don't have it. (I am happy to answer questions on them, I've repaired a few and designed the control electronics for one). Apart from the fact that brightness is controlled by a 3-bit DAC on the motherboard, which results in the CRT grid bias apperaring on the monitor connector (!), the monitor is conventional. There's a uPC1031H2 for the vertical deflection, a discrete transstor horizontal deflection circuit (2 transistor as a monostable, then line driver transformer coupled to the line output transistor). EHT and other voltages>12V come from the flyback transformer as usual.

30th May 2025, 8:37 pm	#11
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 7,745	Re: Vintage Sirius Computer I finally got the Sirius onto my temporary bench, these things seem to get heavier as I get older! Work and the needs of the family give me little spare time sadly. I don't like powering SMPS via lamp limiters or variacs so I gave it full mains. The LED on the front came on no attempt to power the disc drive and after a couple of minutes a lot of smoke and a big bang actually two big bangs. So I pulled it apart and found pretty much what I expected. I have replaced these with modern parts but after trying again no activity from the monitor or disc drive no drama either. Time to check the supply rails Cheers Mike T Attached Thumbnails __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk

30th May 2025, 11:52 pm	#12
ortek_service Nonode Join Date: May 2018 Location: Northampton, Northamptonshire, UK. Posts: 2,801	Re: Vintage Sirius Computer The dreaded RIFA's strike again (well after a delayed time, whilst they are getting hot, until smoking a lot.) And whilst the ones in the AC mains filter shouldn't stop the PSU from working, I can see at least one-more clear-epoxy RIFA that may be in other areas of the circuitry. So wonder if you've changed all the rest of these, even if they haven't burnt-up yet? (although they've no-doubt had their epoxy failed with cracks in it). I have recently had a PSU where a burning-up RIFA had stopped it working, but replacing them all inc. DC-only rated ones had fixed it. Although if you are getting a Power LED, it seems the PSU is probably running OK and there's problems elsewhere.