Search found 8712 matches

by 1024MAK
Mon Jun 17, 2019 6:49 pm
Forum: off-topic
Topic: BASIC finally recognised ...
Replies: 3
Views: 105

Re: BASIC finally recognised ...

Professor John Kemeny, Maths professor Thomas Kurtz, and a group undergraduate students at Dartmouth College created BASIC (Beginner's All-purpose Symbolic Instruction Set). Err, did they change the name? My understanding from the early 1980s is that BASIC stands for Beginner's All-purpose Symbolic...
by 1024MAK
Mon Jun 17, 2019 5:40 pm
Forum: hardware
Topic: Who on here has the earliest Acorn Electron?
Replies: 6
Views: 73

Who on here has the earliest Acorn Electron?

Who on here has the earliest Acorn Electron? We all know (or at least, I hope all Electron owners know) that although Acorn announced an inexpensive computer in 1982, it was not officially launched until the following year. And even then, supplies were limited in the run up to Christmas 1983. So are...
by 1024MAK
Sun Jun 16, 2019 2:53 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL
Replies: 120
Views: 4292

Re: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL

Well, we didn’t think it would be a problem, but we prefer to be upfront with any changes so that everyone is kept fully up to date.

It may not be much of an increase, but it is still different to what has been advertised on here for months.

Mark
by 1024MAK
Sun Jun 16, 2019 1:45 pm
Forum: general
Topic: “Send no money now!” — Electron news from 1982
Replies: 8
Views: 214

Re: “Send no money now!” — Electron news from 1982

There is no way that a machine still in the early stages of development in the summer (assuming it had got that far) would have been ready for mass production and proper launch for December of the same year. That’s only four months. Even if the ULA development had gone quickly and had not hit any sn...
by 1024MAK
Sun Jun 16, 2019 12:40 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL
Replies: 120
Views: 4292

Re: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL

Important Update I have just been informed that the museum has increased it’s prices. The museum entrance fee is now £9 per person per day for adults. - If you are attending the ABug event for the entire weekend (two or more days), the fee will be £18 - to be paid as an £9 museum entrance fee on tw...
by 1024MAK
Sat Jun 15, 2019 8:01 pm
Forum: acorn atom and system
Topic: 2AtomFPGA - successor of Yarrb
Replies: 17
Views: 293

Re: 2AtomFPGA - successor of Yarrb

roland wrote:
Sat Jun 15, 2019 7:25 pm
janrinze wrote:
Sat Jun 15, 2019 6:31 pm
FPGA based Atom's can easily do 40 MHz.
How does CTRL+G sound at that speed :shock:
Suitable as a dog “whistle” :lol:

Mark
by 1024MAK
Sat Jun 15, 2019 5:46 pm
Forum: other vintage computer hardware, software and games
Topic: Epson HX20 - first laptop !EVER! 1981+
Replies: 45
Views: 2272

Re: Epson HX20 - first laptop !EVER! 1981+

also found the adaptor, but it has the wrong plug on end, so useless :? it spits out 9.3V with no load on it. That AC/DC adaptor is most likely an unregulated type (a transformer, rectifier and smoothing capacitor), hence with no load the output voltage will be a lot higher than the voltage it’s ra...
by 1024MAK
Sat Jun 15, 2019 5:16 pm
Forum: hardware
Topic: BBC model B with beep of doom
Replies: 10
Views: 272

Re: BBC model B with beep of doom

So if these do look to be OK, what is the most sensible way to proceed? As the machine worked briefly before you saw the smoke, I suspect there is not much wrong with it. One problem with expansion boards, is the pins in the pin header connectors are larger in diameter compared to the legs of a DIL...
by 1024MAK
Sat Jun 15, 2019 5:08 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL
Replies: 120
Views: 4292

Re: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL

MadeGray wrote:
Sat Jun 15, 2019 5:00 pm
Can you add a second for Sunday please if that’s ok and you have space. put down as Mike Bunce. No table etc no kit just a fellow Bbc nut.
Done :D
List updated.

Mark
by 1024MAK
Sat Jun 15, 2019 4:05 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL
Replies: 120
Views: 4292

Re: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL

Thanks Mark, Much appreciated, add me in as a no kit visitor for the Sunday if that’s ok. I won’t need a table but if anyone wants to look at my 1024k master 86 co pro with a memory fault then I would be very grateful! Thanks very much, put me down for the Sunday please. John Hi John I’ve added you...
by 1024MAK
Sat Jun 15, 2019 2:16 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL
Replies: 120
Views: 4292

Re: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL

Appreciate the post says this is now full but not sure if that’s for booked tables etc? Is it at all possible to pop in for a few hours on the Saturday or Sunday? I dropped into Wakefield for a few hours which was really good to meet people like Daniel, Dave H etc etc. I could also drop back the Po...
by 1024MAK
Sat Jun 15, 2019 10:58 am
Forum: hardware
Topic: BBC model B with beep of doom
Replies: 10
Views: 272

Re: BBC model B with beep of doom

Thanks everyone for the excellent information. :arrow: Could you measure the DC voltage at the following pins: IC6, pins 8,7,6,5 and 4. These are the raw 16, 8, 4, 2 and 1MHz clock signals generated by the video processor IC1, pins 37, 3, and 39. These are the Phi 0, Phi 1, and Phi 2 clocks on the ...
by 1024MAK
Sat Jun 15, 2019 10:45 am
Forum: hardware
Topic: BBC model B with beep of doom
Replies: 10
Views: 272

Re: BBC model B with beep of doom

The S20, S21 and S22 links (jumper shunts) in your photo appear to be correct. Here is a photo showing the correct configuration for normal on board sideways ROMs, as in one of my machines (a BBC B issue 7 board, please ignore the violet and grey wires, they are for a modification): https://stardot....
by 1024MAK
Sat Jun 15, 2019 10:06 am
Forum: hardware
Topic: poorly Master in need of assistance
Replies: 12
Views: 275

Re: poorly Master in need of assistance

In terms of general fault finding, it starts off like this: Get a good quality multimeter, test the +5V (V CC ) supply voltage where the leads from the PSU connect to the main board. Check these connectors are making a good firm connection. Test the +5V (V CC ) supply voltage on a major chip on each...
by 1024MAK
Thu Jun 13, 2019 12:09 am
Forum: hardware
Topic: Master 128 and the long slow beep of doom
Replies: 11
Views: 472

Re: Master 128 and the long slow beep of doom

Elminster wrote:
Wed Jun 12, 2019 12:01 pm
Doesn't the multimeter need to be an RMS type to be accurate measuring DC with AC range? Or did I imagine that.
Not if you only want an indication of how bad (or good) the level of ripple is...

Mark
by 1024MAK
Wed Jun 12, 2019 11:24 am
Forum: hardware
Topic: Master 128 and the long slow beep of doom
Replies: 11
Views: 472

Re: Master 128 and the long slow beep of doom

21W 12V lamp, typical current values at various voltages: At 12V, 1.65A At 6V , 1.1A At 5V , 1A At 3.3V , 0.8A Note the above results do not take into account the slight loss due to a current meter being in circuit. If the PSU is unable to maintain its output between 4.85V and 5.15V with a 12V 21V l...
by 1024MAK
Tue Jun 11, 2019 8:14 pm
Forum: off-topic
Topic: Trying to wire an RS-422 cable
Replies: 2
Views: 76

Re: Trying to wire an RS-422 cable

Yes, try it and see.

RS422, RS423, RS485 and RS232 all should have protection against short circuits etc...

Mark
by 1024MAK
Tue Jun 11, 2019 12:46 pm
Forum: hardware
Topic: 1770 wire links
Replies: 12
Views: 177

Re: 1770 wire links

Or maybe some proper industrial headers for wire links etc...

link/component header

dust covers

:mrgreen:

NB similar parts may be available elsewhere for more or for less money...

Mark
by 1024MAK
Tue Jun 11, 2019 12:55 am
Forum: hardware
Topic: Plus1 Joystick ADC Noise?
Replies: 2
Views: 104

Re: Plus1 Joystick ADC Noise?

There is some info in this thread :wink:

Mark
by 1024MAK
Mon Jun 10, 2019 10:44 pm
Forum: hardware
Topic: A5000 Power Supply Circuit Diagram
Replies: 21
Views: 283

Re: A5000 Power Supply Circuit Diagram

4.95V is well within the required specification. I’d have to study the schematic to be sure what the +12V and -5V supplies are used for. But all the digital logic uses only the +5V supply. So if this is good, the CPU, memory etc... should all all work. But as Duncan says, the true test of the PSU is...
by 1024MAK
Mon Jun 10, 2019 10:34 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL
Replies: 120
Views: 4292

Re: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL

Would it be alright if Sharon comes along to this one? I know we are tight for space; but she asked if she could come along without any prompting. Hi Robert I was asked a similar question earlier by another member. As you have booked a full table, I don’t have a problem with Sharon attending. The o...
by 1024MAK
Mon Jun 10, 2019 1:01 pm
Forum: hardware
Topic: FIXED: Upgraded (in 1980-something) BBC Model A keyboard not working
Replies: 12
Views: 286

Re: FIXED: Upgraded (in 1980-something) BBC Model A keyboard not working

The MOS uses the keyboard in two different modes: autoscan, which generates an interrupt via the 6522 VIA, and “manual” scan to work out which key was actually pressed.

Mark
by 1024MAK
Mon Jun 10, 2019 12:15 pm
Forum: hardware
Topic: Auxiliary power plugs
Replies: 7
Views: 150

Re: Auxiliary power plugs

For the Beeb end see this thread :wink:

Mark
by 1024MAK
Sun Jun 09, 2019 9:12 pm
Forum: hardware
Topic: Electron keyboard disassembly
Replies: 8
Views: 177

Re: Electron keyboard disassembly

The switches may need fifty or so presses to get them working again.

Mark
by 1024MAK
Sun Jun 09, 2019 5:08 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL
Replies: 120
Views: 4292

Re: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL

I suspect the rubber in the foot degraded (chemical reaction) rather than heat. Although chemical reactions are of course speeded up with increased temperatures...

I’ve seen people after feet before, but can’t remember where. So maybe worth searching the forum and the web :wink:

Mark
by 1024MAK
Sun Jun 09, 2019 2:51 pm
Forum: hardware
Topic: Beeb Power Supply Issue
Replies: 28
Views: 1103

Re: Beeb Power Supply Issue

This applies to BBC A, BBC B, BBC B+ and Master 128/512 machines: C1 and C2 are mains voltage interference suppression capacitors, the original Rifa brand are known to fail, and result in smelly smoke escaping when they do fail. So these are a must (unless they have already been renewed). It is easi...
by 1024MAK
Sun Jun 09, 2019 2:34 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - NOW FULL
Replies: 120
Views: 4292

Re: ABUG Cambridge 28th - 30th June 2019 BOOKING THREAD - ONE PLACE LEFT

Hi Simon

So just to be clear, there is no problem with you bringing your wife.
Sorry, I can’t answer the van question.

Will you be there for all three days (Friday afternoon to Sunday)?

Mark
by 1024MAK
Sat Jun 08, 2019 8:23 pm
Forum: hardware
Topic: Help Needed with 6502 Second Processor
Replies: 18
Views: 575

Re: Help Needed with 6502 Second Processor

The end with pin 1 is often marked with a small triangle embossed into the plastic housing of the IDC or box header connector.

Mark
by 1024MAK
Sat Jun 08, 2019 2:11 pm
Forum: for sale / freebies
Topic: For sale: BBC B+, Electron, assorted bits
Replies: 15
Views: 360

Re: For sale: BBC B+, Electron, assorted bits

With forums (and other unspeakable places), there is always a minority that have a good all round knowledge and who post often, plus a few specialist ‘experts’. But the vast majority of members, only rarely post, and often only when they need help. And even then, only when they can’t find an answer ...
by 1024MAK
Sat Jun 08, 2019 11:09 am
Forum: acorn atom and system
Topic: YARRB [SOLD OUT]
Replies: 240
Views: 12180

Re: YARRB

So it could be signal timing edge case then :(

This could be a tricky one...

Mark