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The first two photos...
Mark

I know that you guys are trying to stay retro, but part of the reason for keyboard encoders becoming rare, is due to microcontrollers taking over. And the Sinclair QL uses a microcontroller to process its keyboard matrix (1984). Later other computers did the same (Atari STFM).

Mark

The low tech approach is to use the BBC printer port to control NPN transistors (either individual, like 2N2222, 2N3904, BC337 etc.) or a chip that contains eight transistors like the ULN2803A Octal Darlington Driver which then control a relay. You need relays with change-over relay contacts (SPDT)....

The monitor that is currently connected to my A3020... F890980A-DE59-420F-A19F-04342E589DAD.jpeg 608C1F5F-FD75-4F16-834B-222E323910F4.jpeg (Sorry about the poor quality photos, the iPad mini camera does not like the light output from the CFL in this room when there is a bright glowing square in the ...

Simon, read my reply just above your latest post...

Mark

My A3020 is connected to a VGA LCD monitor and works fine (unless a game wants to use a TV frequency line/frame rate). I’ll bring it and the VGA cable as well as my A3020. It should be noted that some machines don’t like some VGA cable / monitor combinations. I have various Rasp. Pi’s. I don’t have ...

This is a dog friendly venue. However, dogs will only be allowed into the event if their name references some form of Acorn trivia. Snakes will not be permitted under any circumstances. Hopefully I won't be too consumed by all things Acorn to remember to take her out for 'potty' (she doesn't let us...

JudgeBeeb wrote: ↑

Wed Jan 22, 2020 1:29 pm

roland wrote: ↑

Wed Jan 22, 2020 1:03 pm

[n that case I need to give my next hardware project the name 'Misty'

I think the name of MiSTy would have a sufficient nexus with the Beeb (and other retro-hardware).

Umm...

Mark

Looks like great progress Ken

Hence I am definitely interested in at least one, probably two

Mark

Welcome on board Neal!



Enjoy the forum

You can list your Acorn machines vitals here
You can make your confession here
Put yourself on the map by sticking a pin in it at this link

I’m sure we can help with repairing your Beeb

Mark

At one time I think Trenz had some without the headers. So this may be possible if they are still producing these (rather than just selling existing stock).

Mark

cmorley wrote: ↑

Mon Jan 20, 2020 6:34 pm

1024MAK wrote: ↑

Mon Jan 20, 2020 6:30 pm

Yep, definitely still interested

Mark

I'll bring some to ABUG.

Great

Mark

Yep, definitely still interested

Mark

(Also, would this be an appropriate forum for seeking help troubleshooting my board? I'll start another post if I receive positive replies.) Hello Neal, welcome to StarDot :D Before you post about your problems with your board, why don’t you pop over to the ‪ introduce yourself ‬section? Then when ...

I’ve not done much with this machine (apart from play games ). I have not replaced any capacitors. The board is a bit dirty in places. It could do definitely do with a bit of TLC.

Mark

flaxcottage wrote: ↑

Sun Jan 19, 2020 2:36 pm

The screw is secured with locktite and will be stiff to remove.

The surface coating of locktite can be chipped off / removed with a small metal pick or small flat-bladed screwdriver.
You could also try various solvent cleaners, as they may soften the locktite.

Mark

If you can get in at it with pliers, that’s what I would try first. It may be cross-threaded, hence why it was damaged during manufacturing. If not, the options are: Cut a slot in the head and try to use a slotted screwdriver, File two sides of the screw head off, to create two flats, then use an op...

Which screw? Can you show us by posting up a photo please.

Mark

The following photos show a test fit of a test board in a A3020 and are provided so that Chris can see how the test board fits in practice. This test board may look different to the production boards. Once fitted and pushed down, the test board is below the level of the metal screening, so there is ...

The boards are free to ABUG attendees on a first come first serve basis. Just as well that I have a meeting (in Exeter) on Thursday now replacing the training course that I was scheduled to attend (was ending on Friday), so I should be able to arrive on Friday afternoon (or maybe earlier) now :D Ma...

Definitely interested in both.

And yes please, photos please

Mark

I’ve never had a problem with new turned pin sockets. But then again, I’ve also never had a problem with new stamped pin dual wipe sockets either. I currently buy all my turned pin sockets and all my stamped pin dual wipe sockets from Rapid Electronics. I hate the old stamped pin single wipe sockets...

Yes, if the Cub monitors use a 75Ω resistor to terminate the inputs when configured for analogue input.

Mark

If it is expecting a 0.7V analogue level signal and you feed it a 5V digital (TTL) signal, that colour channel will go to maximum intensity (for all three colour channels, that will be bright white). If you leave it like that, it could cause damage. If it is expecting a TTL level signal and feed it ...

If there are indeed ‘jumper shunts’ / links, then yes, it is possible to add a switch. I recommend a rotary switch because three separate circuits need to be switched. So a three pole type. A suitable type is a Taiwan Alpha SR2611F030438F5BD Break Before Make Rotary Switch 3 Pole 4 Way. Rapid carry ...

The following is general advice and information. The particulars of individual cases will be handed via private messages. On the subject of private messages (PMs) on the forum, we don’t block these. They are private between the respective members. The moderators and administrators will only get invo...

There is much more than “temperature controlled” to consider. When working on ground planes, aluminium backed PCBs, modulator cases, screening cans and similar use, it is NOT just the tip temperature that matters. What really matters is heat-flow. This does not just apply to temperature controlled i...

Hi Chris I would like: two suitable for A3020 machines, one suitable for A4000 machines, and two suitable for A5000 machines. So that’s a total of five please [-o< Thanks If you have them ready for January’s ABug, that would be great, but not essential, as I’m not in a rush. So don’t worry if it’s t...

Yes!

In fact, as long as there is sufficient memory mapped or I/O address space, in theory, a Acorn second processor could be connected to many 8 bit systems...

Mark

I’m guessing (as I don’t have the time to read through the thread about the detailed workings of the Electron’s ULA) that the U.K. / European version uses a ULA that only has PAL video timing. Presumably if Acorn had attempted to launch an overseas NTSC version of the Electron, it would have had a U...