Search found 8058 matches

by 1024MAK
Wed Dec 12, 2018 7:37 am
Forum: hardware
Topic: NEC FD1055 jumper settings
Replies: 6
Views: 160

Re: NEC FD1055 jumper settings

In one of the “The Home Computer Course” magazines (link to an archive of the magazines) or the follow on “The Home Computer Advanced Course”, there is a s schematic aspart of a project for a disk drive interface monitor.

Mark
by 1024MAK
Tue Dec 11, 2018 4:58 pm
Forum: hardware
Topic: Model, specification, and upgrades identification
Replies: 7
Views: 171

Re: Model, specification, and upgrades identification

This may also help http://chrisacorns.computinghistory.org.uk/ProductCodes.html . I’m not aware of anything else apart from the web pages you have already linked to. Another member maintains a list of hardware expansions and devices, but this is primarily for recent / new items rather than Acorn or ...
by 1024MAK
Tue Dec 11, 2018 4:48 pm
Forum: hardware
Topic: Strange Pegasus DFS fault
Replies: 25
Views: 444

Re: Strange Pegasus DFS fault

How are you powering your programmer? A lot of the cheap designs made in China don’t have a very good DC/DC step up converter, they struggle to get and maintain the required 21V programming voltage at the current required by older NMOS EPROM chips. So if you are using a 5V supply or USB lead, and it...
by 1024MAK
Mon Dec 10, 2018 3:38 pm
Forum: wanted
Topic: Wanted: Microvitec Cub Monitor Repair(er)
Replies: 9
Views: 160

Re: Wanted: Microvitec Cub Monitor Repair(er)

Hmm, normally the screen from a Beeb almost entirely fills a 4:3 aspect ratio CRT display. It may be that the voltage on one of the main supply rails is/was low, or, as it is a black cased model, it is more likely that it was set up for use with a Sinclair QL. The video signal from a QL is too wide ...
by 1024MAK
Mon Dec 10, 2018 12:03 pm
Forum: hardware
Topic: Strange Pegasus DFS fault
Replies: 25
Views: 444

Re: Strange Pegasus DFS fault

Is it dead, probably not. Internally EPROMs use the stored charge memory cell system, when a voltage (charge) level on a small ‘capacitor’ is used to record the state. When a read is performed, voltage comparators decide if the analogue voltage level is above or below a threshold, and hence is it a ...
by 1024MAK
Mon Dec 10, 2018 11:45 am
Forum: wanted
Topic: Wanted: Microvitec Cub Monitor Repair(er)
Replies: 9
Views: 160

Re: Wanted: Microvitec Cub Monitor Repair(er)

Lack of width, lack of height or both?

Mark
by 1024MAK
Sun Dec 09, 2018 12:30 am
Forum: hardware
Topic: This is not a language
Replies: 68
Views: 1467

Re: This is not a language

4.38V is well outside the specification :shock:

I’m surprised there were no other problems!

I’m glad to hear that you are back up and running 8)

Thanks for reporting back =D>

Have fun :D

Mark
by 1024MAK
Sat Dec 08, 2018 9:44 pm
Forum: stardot.org.uk
Topic: too many logins??
Replies: 4
Views: 182

Re: too many logins??

It’s the machines ganging up with one another after hearing about your comments on ADFS.... :lol:

Say hello to Skynet :mrgreen:

Mark
by 1024MAK
Sat Dec 08, 2018 10:39 am
Forum: hardware
Topic: Strange Pegasus DFS fault
Replies: 25
Views: 444

Re: Strange Pegasus DFS fault

It is worthwhile removing all the socketed chips. Then visually inspecting as much of the board as possible. Certainly do as Martin suggests with regards to testing the EPROM and SRAM chips. There is nothing special about the SRAM chip, so if you have other devices that also use the same size SRAM c...
by 1024MAK
Sat Dec 08, 2018 10:16 am
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 367

Re: Loss of output on Electron RGB Port

GREAT NEWS! I found a weird voltage drop in my C-sync signal coming out of chip 14 so I replaced that and now the old Elk works again! I think replacing IC 19 was also a necessary step as suggested above. So I just want to thank everyone here who read the thread and an extra special thanks to every...
by 1024MAK
Fri Dec 07, 2018 9:21 am
Forum: introduce yourself
Topic: Greeting
Replies: 10
Views: 256

Re: Greeting

Welcome on board Symo!

:D :D :D

Enjoy the forum :D

You can make your confession here :mrgreen:
Put yourself on the map by sticking a pin in it at this link :P
If you have any real gear, you can list your Acorn machines vitals here

Mark
by 1024MAK
Thu Dec 06, 2018 10:43 pm
Forum: hardware
Topic: Strange Pegasus DFS fault
Replies: 25
Views: 444

Re: Strange Pegasus DFS fault

What is the state of the socket contacts?

Mark
by 1024MAK
Thu Dec 06, 2018 10:24 am
Forum: bbcmicro.co.uk
Topic: Quoted text in Notes is too big, esp. on iOS
Replies: 6
Views: 177

Re: Quoted text in Notes is too big, esp. on iOS

iOS does that on some other web sites.

Mark
by 1024MAK
Wed Dec 05, 2018 9:17 am
Forum: emulators
Topic: More interesting 6522 VIA emulation discrepancies
Replies: 28
Views: 502

Re: More interesting 6522 VIA emulation discrepancies

...but it's also possible that the actual behaviour of the VIA in the Master is different too (it's a CMOS version, right?). In the two Master 128 machines that I checked, yes, CMOS versions of the VIAs are fitted. Both of these IIRC are issue 2 PCBs. But I believe that at least one member here has...
by 1024MAK
Mon Dec 03, 2018 11:41 am
Forum: hardware
Topic: I2C 4 U
Replies: 296
Views: 18372

Re: I2C 4 U

I use the FileApp application to zip and unzip stuff on the iPad mini that I use. Unzipping is normally perfectly fine. Zipping up is also good. But sometimes files don’t show up in the iOS file browser. So I copy the file to another suitable application (“Notes” is easiest). Then copy the file back...
by 1024MAK
Mon Dec 03, 2018 4:10 am
Forum: general
Topic: How much of this is just rose-tinted specs?
Replies: 21
Views: 583

Re: How much of this is just rose-tinted specs?

If people don’t tinker anymore, why are there so many Arduino projects on the Internet? Let alone other microcontroller projects and Raspberry Pi projects... And although nowhere near as popular as the above areas, there are various sites that have people building projects using 6502, Z80 or other m...
by 1024MAK
Sun Dec 02, 2018 11:46 pm
Forum: hardware
Topic: Sharing a Disk Drive
Replies: 21
Views: 1524

Re: Sharing a Disk Drive

Yes, putting a knot in the mains cable is frowned upon.

A proper cable clamp or cable gland should be used.

And yes Ian, the earth wire should be securely connected to the metalwork of the case.

Mark
by 1024MAK
Sun Dec 02, 2018 6:43 pm
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 367

Re: Loss of output on Electron RGB Port

Hi Dave, yes, link LK4, but I just wanted to confirm that yell0w_lantern means that and not anything else...

Mark
by 1024MAK
Sun Dec 02, 2018 6:41 pm
Forum: hardware
Topic: Sharing a Disk Drive
Replies: 21
Views: 1524

Re: Sharing a Disk Drive

It’s possible that the top PCB is the same as the bottom PCB, but with track cuts and the power supply end cut off...

A “interesting” and crude way of cutting costs :lol:

Mark
by 1024MAK
Sun Dec 02, 2018 6:36 pm
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 367

Re: Loss of output on Electron RGB Port

Apart from your multimeter, do you have any other test equipment?

What model and make is your multimeter?

Mark
by 1024MAK
Sun Dec 02, 2018 6:33 pm
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 367

Re: Loss of output on Electron RGB Port

Also, do you get grey levels as well as black and white?

Mark
by 1024MAK
Sun Dec 02, 2018 6:30 pm
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 367

Re: Loss of output on Electron RGB Port

yell0w_lantern wrote:
Sat Dec 01, 2018 5:08 am
Acorn Electron +1 with color mod
What do you mean by colour mod?

Which issue board do you have?

Mark
by 1024MAK
Sun Dec 02, 2018 5:43 pm
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 367

Re: Loss of output on Electron RGB Port

By default, both the BBC B and the Electron only output a monochrome (black and white) video signal on the composite video outputs.

Mark
by 1024MAK
Sun Dec 02, 2018 5:23 pm
Forum: general
Topic: Today I built ...
Replies: 45
Views: 3164

Re: Today I built ...

It's one of these: http://searle.hostei.com/grant/Multicomp/ mated to one of these: https://www.retrobrewcomputers.org/doku.php?id=boards:sbc:multicomp:cycloneii-c:start running one of these: http://obsolescence.wixsite.com/obsolescence/multicomp-fpga-cpm-demo-disk . In essence, a CP/M box overcloc...
by 1024MAK
Sun Dec 02, 2018 10:47 am
Forum: general
Topic: Today I built ...
Replies: 45
Views: 3164

Re: Today I built ...

jonb wrote:
Mon Nov 26, 2018 12:44 pm
For my part I built a mystery device:

...

But what is it?
by 1024MAK
Sun Dec 02, 2018 10:47 am
Forum: general
Topic: Today I built ...
Replies: 45
Views: 3164

Re: Today I built ...

bprosman wrote:
Sat Dec 01, 2018 6:06 pm
Today I built a Godil adapter.
Nice 8)
=D>

Mark
by 1024MAK
Sun Dec 02, 2018 10:17 am
Forum: hardware
Topic: Sharing a Disk Drive
Replies: 21
Views: 1524

Re: Sharing a Disk Drive

Don’t stop there, whip it’s cover off! :lol:

We all want to ogle it’s insides...

Mark
by 1024MAK
Sat Dec 01, 2018 10:26 am
Forum: hardware
Topic: Electron Plus 3 Help
Replies: 17
Views: 327

Re: Electron Plus 3 Help

3½” High Density (HD) floppy disks are not backwards compatible with double density (DD) or older disk drives. For short term temporary use, it may be possible to use them if you can completely erase the existing magnetic field on the disk by using a suitable electrical demagnetiser. But if you do, ...
by 1024MAK
Sat Dec 01, 2018 9:47 am
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 367

Re: Loss of output on Electron RGB Port

Later issue Electrons have a logic chip to buffer the red, green and blue video signals to the RGB connector. If this is damaged by external voltages, you will loose one or more of the red, green and blue video signals. This chip is not shown in the schematics (unless anyone knows of a schematic fo...