Search found 24 matches

by drjaymz
Mon Jan 03, 2022 7:27 pm
Forum: 8-bit acorn hardware
Topic: Non-erasing EPROM
Replies: 16
Views: 671

Re: Non-erasing EPROM

I once saw someone struggling to erase some eproms, I didn't want to interfere by removing the stickers from the windows.
by drjaymz
Wed Dec 29, 2021 6:17 pm
Forum: 8-bit acorn hardware
Topic: Cub monitor suspend
Replies: 18
Views: 559

Re: Cub monitor suspend

Something like this: B92E5935-36D3-4963-8DB2-274B01A97D4D.jpeg Simulation here (click the switch :wink: ). Obviously you will have to play around with the resistor and capacitor valves to suit your relay. For the two diodes shown, silicon 1N4001 should be okay, but if your relay is not keen on a lo...
by drjaymz
Tue Dec 28, 2021 10:42 am
Forum: 8-bit acorn hardware
Topic: Cub monitor suspend
Replies: 18
Views: 559

Re: Cub monitor suspend

1024MAK wrote:
Tue Dec 28, 2021 12:33 am
It is possible to add in a delayed off. But obviously a bit more circuitry is needed.

Mark
could just use a Diode-R-C and Transistor to achieve this. Fast charge for start-up and slow decay to delay the turn off.
by drjaymz
Mon Dec 27, 2021 6:28 pm
Forum: 8-bit acorn hardware
Topic: Cub monitor suspend
Replies: 18
Views: 559

Re: Cub monitor suspend

I would definitely want to add a 20 second delay. The number of times I power cycle my beeb! For simplicity I probably wouldn't. But the reason you might add one is because they have a ntc inrush suppression which only works from cold. I don't tend to power cycle the beep using control break usuall...
by drjaymz
Sat Dec 25, 2021 10:12 am
Forum: 8-bit acorn hardware
Topic: Cub monitor suspend
Replies: 18
Views: 559

Re: Cub monitor suspend

That was my first thought but I did wonder if it would be a bit much. I thought the 5V was more like 20ma. Tbf I haven't checked the schematic yet. On an issue 7 board, I measured 0.1Ω (using a good quality multimeter, set up to exclude the meter lead resistance) between the +5V/VCC supply terminal...
by drjaymz
Sat Dec 25, 2021 10:05 am
Forum: 8-bit acorn hardware
Topic: Cub monitor suspend
Replies: 18
Views: 559

Re: Cub monitor suspend

I mentioned it because I can't really see why it wouldn't have been done previously via a watford electronics kit or even from Microvitec themselves except for the extra 1.50 in components.... In a sense you answered you own question by mention of the energy star guys. These things were made before...
by drjaymz
Fri Dec 24, 2021 7:43 pm
Forum: 8-bit acorn hardware
Topic: Cub monitor suspend
Replies: 18
Views: 559

Re: Cub monitor suspend

A suitable 5V electromagnetic relay will have a coil resistance of 70Ω or greater. At 5V, that will only draw a current of 71mA. The 5V pin on the RGB port should have no trouble supplying this current. Mark That was my first thought but I did wonder if it would be a bit much. I thought the 5V was ...
by drjaymz
Fri Dec 24, 2021 9:27 am
Forum: 8-bit acorn hardware
Topic: Cub monitor suspend
Replies: 18
Views: 559

Re: Cub monitor suspend

So, its needed simply because my current monitor is very quiet when no signal and no indication its on except the neon. We've left it om a few nights which is not really what you want to do, both for live and if you saw my restoration video the LOPT is not really to be trusted on its own. I'd go wit...
by drjaymz
Thu Dec 23, 2021 4:34 pm
Forum: stardot FORUM
Topic: Clicking login shows message about accepting cookies
Replies: 1
Views: 321

Re: Clicking login shows message about accepting cookies

I found the problem, I have a plugin called 'I don't care about cookies' that is supposed to accept all cookies but obviously doesn't work properly on this site.
by drjaymz
Thu Dec 23, 2021 4:26 pm
Forum: stardot FORUM
Topic: Clicking login shows message about accepting cookies
Replies: 1
Views: 321

Clicking login shows message about accepting cookies

On my main pc running chrome I can't log in. I get a page saying I need to accept cookies to continue. I don't get the cookies notice to accept them.

I have gone in developer mode to delete all data related to statdot to load from fresh but cannot get in.
by drjaymz
Thu Dec 23, 2021 4:22 pm
Forum: 8-bit acorn hardware
Topic: Cub monitor suspend
Replies: 18
Views: 559

Cub monitor suspend

Since the cub gets a 5v supply from the beeb at reasonable current, then why can't this signal be used to turn the monitor on and off? I don't think I'd like to try to directly run a relay from it but a modified sonoff smart switch will provide its own supply and could use an opto coupler only becau...
by drjaymz
Sun Nov 07, 2021 1:11 pm
Forum: 8-bit acorn hardware
Topic: Beeb black plastic surround
Replies: 63
Views: 7462

Re: Beeb black plastic surround

I recently spruced up a tired old control panel in a 1970s plane that was all dymo tape of various vintages. It looked a mess before and the result was ok although not quite as good as I'd hoped. I used crownhill, a guy called Lester Wilson. 20211107_105518.jpg I took a picture today of it so you ca...
by drjaymz
Tue Nov 02, 2021 5:37 pm
Forum: 8-bit acorn hardware
Topic: Restoring an early BBC Micro
Replies: 39
Views: 1748

Re: Restoring an early BBC Micro

Yes, the BBC wanted linear supplies for fear of interference in the recording studios. I have an issue 3 which is a switched mode so must have changed between 2 and 3. Inside the ubiquitous cub monitor there is a huge switch mode so was a bit of a daft idea really. You'll need a multimeter. A linear...
by drjaymz
Sat Oct 23, 2021 5:10 pm
Forum: new projects and releases: demoscene
Topic: New BBC demo written in TRSE
Replies: 13
Views: 1122

Re: New BBC demo written in TRSE

What do you have to do to run it assuming bbc b and turbo mmc?
by drjaymz
Fri Oct 22, 2021 1:45 pm
Forum: 8-bit acorn hardware
Topic: Fun with mouldy Cub Microvitec 1431
Replies: 6
Views: 413

Re: Fun with mouldy Cub Microvitec 1431

Here is the video I promised. https://www.youtube.com/watch?v=qk1uIRNvz3U I put a lot of work into that production, its very time consuming, I enjoyed it but I won't give up my day job. I also know that people sometimes get a bit funny about promoting videos etc. I'm not a youtube content producer [...
by drjaymz
Mon Oct 11, 2021 8:55 pm
Forum: 8-bit acorn hardware
Topic: Fun with mouldy Cub Microvitec 1431
Replies: 6
Views: 413

Re: Fun with mouldy Cub Microvitec 1431

I was so certain the problem has to be the tda1180p that I decided to clean up the monitor, removed the tube and panel beat it back into a perfect cube or cub. Today the chip arrived so I quickly bathed the kids and read them two stories at double speed then legged it to the man cave. Double triple ...
by drjaymz
Sat Oct 09, 2021 1:15 pm
Forum: 8-bit acorn hardware
Topic: Fun with mouldy Cub Microvitec 1431
Replies: 6
Views: 413

Re: Fun with mouldy Cub Microvitec 1431

Pulled the chip, put a socket in and replaced the 4n7 polystyrene capacitor. I also removed the first transistor downstream of the TDA and it checks out working fine so I have put that back. Just waiting for the chip to see if it bursts into life. I also took all the panels off and panel beat them b...
by drjaymz
Fri Oct 08, 2021 11:04 am
Forum: 8-bit acorn hardware
Topic: Fun with mouldy Cub Microvitec 1431
Replies: 6
Views: 413

Re: Fun with mouldy Cub Microvitec 1431

You know what? I really enjoyed it so far as well. I have a man shed full of kit but since I had kids time is the one thing I have been very short of so most of my projects involve ESP32 chips and the like, but its been really good to get back to the beeb. I really don't want this monitor to die - t...
by drjaymz
Fri Oct 08, 2021 9:32 am
Forum: 8-bit acorn hardware
Topic: Fun with mouldy Cub Microvitec 1431
Replies: 6
Views: 413

Fun with mouldy Cub Microvitec 1431

Hi all, I acquired a mouldy monitor from a garage clearance that last operated in 1991. Its been very damp and was in pretty poor shape. I set to work cleaning it up, connectors etc and doing a capacitance / esr check on the components. I found dry joints on the big resistors which is pretty common ...
by drjaymz
Tue Sep 28, 2021 11:26 am
Forum: introduce yourself
Topic: Hi from Stourbridge
Replies: 13
Views: 533

Re: Hi from Stourbridge

Welcome, there is a Google map of members who have added themselves which may aid your search, at least once you have posted 25 times and can pm. I look forward to you videos and sharing your adventure. Thanks for that, I will keep an eye out for that. Acorn enthusiasts were relatively thin in the ...
by drjaymz
Mon Sep 27, 2021 2:36 pm
Forum: introduce yourself
Topic: Hi from Stourbridge
Replies: 13
Views: 533

Re: Hi from Stourbridge

Welcome to the Forum, drjaymz (or should that be Trinity? :D ) . . . Enjoy . . . Dave H. Interesting to see what they start with. They show her how to send emails to the teacher and they point out the different parts of the computer - but email is so abstract from the computer I find it hard to und...
by drjaymz
Mon Sep 27, 2021 2:31 pm
Forum: introduce yourself
Topic: Hi from Stourbridge
Replies: 13
Views: 533

Re: Hi from Stourbridge

Lardo Boffin wrote:
Mon Sep 27, 2021 12:16 pm
Welcome!

Stourbridge west midlands? If so I used to live just up the road but sadly moved away some time ago.
Sadly? normally you go somewhere better!?
by drjaymz
Mon Sep 27, 2021 2:27 pm
Forum: introduce yourself
Topic: Hi from Stourbridge
Replies: 13
Views: 533

Re: Hi from Stourbridge

Welcome to the forum. The BBC Micro is not that far removed from what we used to call "steam computing", i.e. cards in and printer out (or even paper tape). I still get misty-eyed when I think about the old kit, and boy, would I love to have a paper tape reader and punch. The punch cards ...
by drjaymz
Mon Sep 27, 2021 9:19 am
Forum: introduce yourself
Topic: Hi from Stourbridge
Replies: 13
Views: 533

Hi from Stourbridge

Hi all, I currently live in Stourbridge. Back in the good old days I didn't actually own a BBC because they were very expensive but my mother worked evenings at Derbyshire Collage of Higher Education. One day due to a childcare fail I had to go with her, I was about 5. She would run the labs until 9...

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