Search found 423 matches

by Steve M
Mon Jun 19, 2017 1:54 am
Forum: Mags and books
Topic: Any spare French books ?
Replies: 14
Views: 10524

Re: Any spare French books ?

Some are not as good as you might hope - but some books are very useful.

I have a list up above. If you want any of the books listed send my a bundle of notes and you can have some :)
by Steve M
Sun Jun 18, 2017 5:28 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 2442

Re: Transformer/ power supply

I'll try and do some pics. It's basically a black metal box. Not very exciting. The original configuration was with a single 3" drive right in the middle. There's a metal blanking plate which hides where a second drive can sit to the right. So it's a black box with a slot in the middle - or a black ...
by Steve M
Sat Jun 17, 2017 10:04 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 2442

Re: Transformer/ power supply

I will try to make a schematic from that power supply, but can't clearly see the track on the "bottom" side of your picture, but it looks really weird to have a tap of the transformer to feed directly the 7805, it should have a bridge rectifier before. And if the 4700uF capacitor has failed, the 78...
by Steve M
Sat Jun 17, 2017 12:45 am
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 2442

Re: Transformer/ power supply

I measured without a load, so I think both voltages are probably down. (The 12v was 11.85v or something.) I expected it to be more without a load - not sure if that's right, but when I measured a different variable voltage power supply it was putting out more than the voltage it was set to. I've got...
by Steve M
Thu Jun 15, 2017 10:03 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 2442

Re: Transformer/ power supply

So I'll change the voltage regulator. Should that sort it?
by Steve M
Thu Jun 15, 2017 9:27 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 2442

Re: Transformer/ power supply

Hmm. I'm getting just under 12V and around 3.8V

Is guess 3.8 is low - but is it enough to power a floppy drive?

Drives won't fire up. I tested the drive in my other system and it works.

Maybe the interface is faulty?
by Steve M
Wed Jun 14, 2017 8:06 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 2442

Re: Transformer/ power supply

Here's a shot showing it is a Cumana power supply.
by Steve M
Wed Jun 14, 2017 8:03 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 2442

Re: Transformer/ power supply

Here's a picture Two voltage regulators 7805 and 7812. I'm guessing 5V and 12 V Axial capacitors 16V 4700uf and 25V 2200uf There's a bridge rectifier RS402L Can't get one of these very easily. Could I substitute a similar one ? Havent' poked my probes at it. I'm a bit scared of 240V. But the interfa...
by Steve M
Wed Jun 14, 2017 5:15 pm
Forum: Technical questions
Topic: Oric Atmos resets after a few seconds ... when not grounded
Replies: 38
Views: 12831

Re: Oric Atmos resets after a few seconds ... when not grounded

The twin EPROM was a feature on the Oric-1. Once a manufactured ROM was fitted it was in a single case and IC11 wasn't needed. There should be such a thing as a twin ROM Atmos. I have seen people burning there own ROMs to get an Atmos working - but it's an oddity. https://www.thefuturewas8bit.com/in...
by Steve M
Wed Jun 14, 2017 4:53 pm
Forum: Technical questions
Topic: 65C02 CPU
Replies: 3
Views: 809

Re: 65C02 CPU

So you cut pin 1 ?

I had a 65c02 in my Atmos for years. Worked fine with Cumana. I didn't cut any pins or joins others.
by Steve M
Tue Jun 13, 2017 11:37 pm
Forum: Technical questions
Topic: ORIC ULA on a CPLD ?
Replies: 12
Views: 2431

Re: ORIC ULA on a CPLD ?

Dr Paul could be found online some time ago. I can't find him now. I think Dave Dick interviewed him back around 1998 or so. I guess he could be retired now.

I would try asking Paul Kaufman but he never replied when I asked him something on Facebook. He hasn't posted anything since 2009.
by Steve M
Tue Jun 13, 2017 10:37 pm
Forum: Technical questions
Topic: ORIC ULA on a CPLD ?
Replies: 12
Views: 2431

Re: ORIC ULA on a CPLD ?

Tangerine always made a thing about their expertise in ULA design. There was a picture in one article about Oric that showed a £100,000 design computer used to design ULAs. So either they did design it - or they lied a lot. Allegedly Dr Paul Johnson had a drawing of the ULA on his wall, but he would...
by Steve M
Tue Jun 13, 2017 10:11 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 2442

Transformer/ power supply

I have a Opelco (Opel) system. This is basically a Cumana interface in a larger case with an extra power supply to power the floppy drives. Mine has a dual power transformer for the drives i.e. it has two outputs. This isn't working. So I'm looking for a replacement - is there any chance? Where can ...
by Steve M
Tue Jun 13, 2017 10:02 pm
Forum: Technical questions
Topic: Oric Atmos resets after a few seconds ... when not grounded
Replies: 38
Views: 12831

Re: Oric Atmos resets after a few seconds ... when not grounded

There are several tracks cut that I can see on the board. The blue wires may be connecting differently - I'm not sure what is going on there. I'd be inclined to make a note of the connection and then remove and reinstate the cut tracks. (Is this a bad idea ??) There's a capacitor stuck on the 74ls04...
by Steve M
Fri May 26, 2017 4:38 pm
Forum: General Discussion
Topic: Oric Atmos PSU Specs
Replies: 15
Views: 3814

Re: Oric Atmos PSU Specs

Thanks. Copied the description and found some on Ebay. :)
http://www.ebay.co.uk/itm/5-x-DC-Female ... Swn7JYEyaA