Search found 787 matches

by Steve M
Wed Jun 21, 2017 12:04 pm
Forum: Technical questions
Topic: Compatible transister ?
Replies: 5
Views: 8893

Re: Compatible transister ?

Thanks.
by Steve M
Tue Jun 20, 2017 9:09 pm
Forum: Technical questions
Topic: Compatible transister ?
Replies: 5
Views: 8893

Compatible transister ?

Is the BC 547 compatible with the BC184 used on the Oric ?

This chap has them on his Oric but the spec says BC184.
https://www.youtube.com/watch?v=hnQKjJMuwQ0
by Steve M
Mon Jun 19, 2017 10:25 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 29257

Re: Transformer/ power supply

I got the big capacitors and swapped those and got over 5V so tested the system. Drive lights went on but it wouldn't boot. So I guess the interface is faulty too. I tried swapping drives just to see if the drive was duff but now the drives won't light up either. So maybe the power supply has gone a...
by Steve M
Mon Jun 19, 2017 1:14 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 29257

Re: Transformer/ power supply

Wasn't able to get a sensible resistance reading.

The other capacitors are 104, (as used on the Cumana interface).

Need to reassemble it before trying to get any other readings. Took some pictures for Didier though :)
by Steve M
Mon Jun 19, 2017 1:54 am
Forum: Mags and books
Topic: Any spare French books ?
Replies: 14
Views: 29462

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: 29257

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 b...
by Steve M
Sat Jun 17, 2017 10:04 pm
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 29257

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 fail...
by Steve M
Sat Jun 17, 2017 12:45 am
Forum: Technical questions
Topic: Transformer/ power supply
Replies: 23
Views: 29257

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: 29257

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: 29257

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: 29257

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: 29257

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: 51937

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: 6576

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: 13
Views: 18155

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.