Search found 141 matches

by stephen_usher
Tue Nov 03, 2020 10:19 am
Forum: 8-bit acorn software: other
Topic: Any short type-ins for unattended Beebs?
Replies: 170
Views: 22506

Re: Any short type-ins for unattended Beebs?

I did a few simple programs for people to type in for an exhibit at the Oxford Museum of the History of Science back in 2014, with a Beeb and a Sinclair QL. I'll attach the PDFs below.
by stephen_usher
Tue Nov 03, 2020 8:39 am
Forum: general
Topic: Raspberry Pi 400
Replies: 50
Views: 1605

Re: Raspberry Pi 400

Should have had red function keys to hark back to the original Archimedes. :-)
by stephen_usher
Fri Oct 30, 2020 6:23 pm
Forum: general
Topic: Today I received.....
Replies: 6058
Views: 641290

Re: Today I received.....

Leew wrote:
Fri Oct 30, 2020 9:14 am
I have the Acorn badged one, buried somewhere deep in the bowels of my garage. I think I picked it up at a car boot quite a number of years ago (10+). It attracted me because it was an Acorn printer and I had never seen one before...
If you need any print heads I've a small box of them. :-)
by stephen_usher
Fri Oct 30, 2020 8:10 am
Forum: general
Topic: Today I received.....
Replies: 6058
Views: 641290

Re: Today I received.....

345FE799-745A-4974-B139-3523A63C67A9.jpeg Even the fuse holder is Acorn green! When were these actually sold? I can’t find a mention in any price lists, dealer ads in magazines, or any reviews. The only mention I’ve ever found was in “The Acorn Guide to the Micro” magazine supplement. Edit: Dec ‘82...
by stephen_usher
Thu Oct 08, 2020 8:09 am
Forum: 8-bit acorn hardware
Topic: Another faulty BBC B
Replies: 5
Views: 310

Re: Another faulty BBC B

Glad that you got it working
by stephen_usher
Mon Oct 05, 2020 6:27 pm
Forum: 8-bit acorn hardware
Topic: Another faulty BBC B
Replies: 5
Views: 310

Re: Another faulty BBC B

Whilst you're waiting for the chip to arrive you can still do some checks with a multimeter. Test continuity between IC15 and IC14 (data lines) and the memory (data lines). It *could* be a broken trace. Concentrate on D0 and D1. Oh, and you can check the RAS and CAS lines on the RAM chips with your ...
by stephen_usher
Sun Oct 04, 2020 8:39 pm
Forum: 8-bit acorn hardware
Topic: Another faulty BBC B
Replies: 5
Views: 310

Re: Another faulty BBC B

It looks like the teletext chip is getting the bottom two bits of the byte as zero. I'd look at the data bus before the address bus. IC14 buffers between the CPU and main memory and IC15 between the memory data bus and the video processor. Now seeing as BASIC seems to be running, my suspicion would ...
by stephen_usher
Sun Aug 23, 2020 1:47 pm
Forum: general
Topic: Today I received.....
Replies: 6058
Views: 641290

Re: Today I received.....

Nice pizza box Stephen! They do come up occasionally for reasonable prices. I scored an IPX with keyboard and Sun monitor for postage as the owner was moving house and wanted rid. It's ex Bath Uni Maths department. Just needed a battery hack for the NVROM and it's a good 'un. I was given an UltraSp...
by stephen_usher
Sat Aug 22, 2020 7:40 pm
Forum: general
Topic: Today I received.....
Replies: 6058
Views: 641290

Re: Today I received.....

Nice pizza box Stephen! They do come up occasionally for reasonable prices. I scored an IPX with keyboard and Sun monitor for postage as the owner was moving house and wanted rid. It's ex Bath Uni Maths department. Just needed a battery hack for the NVROM and it's a good 'un. I was given an UltraSp...
by stephen_usher
Wed Aug 19, 2020 7:58 pm
Forum: 32-bit acorn hardware
Topic: Today I overclocked my A3010
Replies: 442
Views: 49435

Re: Today I overclocked my A3010

I must admit that I can't remember testing from a floppy disk, only the hard disk. I wonder if a non-whole frequency messes that up. Have you tried a 72MHz crystal, or even better the hack using the on-board 72MHz crystal by fixing a resistor (see my previous post), which means that the CPU and the ...
by stephen_usher
Wed Aug 19, 2020 7:27 pm
Forum: general
Topic: Today I received.....
Replies: 6058
Views: 641290

Re: Today I received.....

I "accidentally" won an eBay auction...
IMG_1989.jpg
Oops. Well, it'll be useful in porting the latest OpenSSH to SunOS 4.1.4. A bit faster than the SPARCstation 5.
by stephen_usher
Wed Aug 19, 2020 7:24 pm
Forum: 32-bit acorn hardware
Topic: Today I overclocked my A3010
Replies: 442
Views: 49435

Re: Today I overclocked my A3010

So, using the built-in IDE interface?
by stephen_usher
Sun Jul 12, 2020 10:58 am
Forum: 8-bit acorn hardware
Topic: Model B - possible faulty cassette interface?
Replies: 30
Views: 1841

Re: Model B - possible faulty cassette interface?

At this point you may need an oscilloscope to determine if the ULA is getting the correct signal. After the tape signal is amplified by the op-amp once it goes through some transistors and back in again before going on to the ULA. These components are between the op-amp and the ULA chips. Actually, ...
by stephen_usher
Wed Jul 08, 2020 7:15 pm
Forum: 8-bit acorn hardware
Topic: Model B - possible faulty cassette interface?
Replies: 30
Views: 1841

Re: Model B - possible faulty cassette interface?

Julz wrote:
Sun Jul 05, 2020 5:02 pm
Thanks, Kazzie.

Yes, the chips have all arrived.

I will attempt to replace ICs 7 & 35 and report back.

Your help, and that other the other members who posted here, is much appreciated. Thanks again.
Any news? You're leaving us all in suspense.
by stephen_usher
Mon Jul 06, 2020 6:08 pm
Forum: 8-bit acorn hardware
Topic: Model B - possible faulty cassette interface?
Replies: 30
Views: 1841

Re: Model B - possible faulty cassette interface?

Yep, the ULA is invisible, or on holiday. :-)
by stephen_usher
Thu Jul 02, 2020 8:54 pm
Forum: 32-bit acorn hardware
Topic: (Project) DIY Ethernet cards for Acorn A4 and A4000 (ALA66 and mini-Podule)
Replies: 7
Views: 592

Re: (Project) DIY Ethernet cards for Acorn A4 and A4000 (ALA66 and mini-Podule)

An excellent project! My A4000's crying out for an ethernet mini-podule.
by stephen_usher
Wed Jul 01, 2020 7:59 pm
Forum: 8-bit acorn hardware
Topic: Scalers / line doublers which are BBC friendly
Replies: 10
Views: 1001

Re: Scalers / line doublers which are BBC friendly

I use an OSSC with my Model B and Master. I use a RGB to scart cable which goes into the OSSC scart input. I get great results with the 0.85 firmware. I have an OSSC, but I have problems when using it with Mode 7 - the characters oscillate vertically, in a seemingly random way, meaning that when yo...
by stephen_usher
Tue Jun 30, 2020 1:39 pm
Forum: 8-bit acorn hardware
Topic: Model B+ boot problems
Replies: 13
Views: 644

Re: Model B+ boot problems

I've just recently had to swap out yet another of the Hitachi RAM chips in my B+ 128K. I just died whilst in storage in the last couple of months. I would have struggled to diagnose the issue without an oscilloscope. IMHO it's THE essential tool for retro-computing maintenance, along with a multimet...
by stephen_usher
Tue Jun 30, 2020 10:38 am
Forum: 8-bit acorn hardware
Topic: Model B - possible faulty cassette interface?
Replies: 30
Views: 1841

Re: Model B - possible faulty cassette interface?

Yep, you need a multimeter. If you look on the far left of the circuit board, next to the power supply, there's one of the wires which plugs in which is not red or black. Pull this off the spade connector on the circuit board. Now pull one of the black ones. Push the black pointy bit into the black ...
by stephen_usher
Mon Jun 29, 2020 1:03 pm
Forum: 8-bit acorn hardware
Topic: Model B - possible faulty cassette interface?
Replies: 30
Views: 1841

Re: Model B - possible faulty cassette interface?

I had this on my machine.

In the end it was a combination of the power supply -5V output (dead capacitor), a partly dead ULA and a fried opamp.

Without the working -5V the opamp won't work, so check that first as it's simple to do.
by stephen_usher
Fri Jun 26, 2020 8:27 pm
Forum: other vintage hardware, software and languages
Topic: Cleaning a Vectrex PCB
Replies: 6
Views: 580

Re: Cleaning a Vectrex PCB

Dish washer?
by stephen_usher
Fri Jun 19, 2020 5:28 pm
Forum: 32-bit acorn hardware
Topic: (Repair) A4000 motherboard resurrection
Replies: 15
Views: 1246

Re: (Repair/Project) A4000 motherboard resurrection

I could do with an ethernet in mine.... If you find a useful source I'd be interested. (I can do 10Base2 and 10BaseT).

Oh, and if you can get some fast RAM overclocking with a crystal in the X100 location is a doddle.

(Or merely a resistor in the right place...)
IMG_1804.jpg
by stephen_usher
Fri Jun 19, 2020 8:37 am
Forum: off-topic
Topic: LOLPRICE
Replies: 3019
Views: 359096

Re: LOLPRICE

I doubt you'll beat this optimistic price for an Amstrad CPC664.
104288250_10158223231344000_808907334521307244_n.jpg
by stephen_usher
Fri Jun 05, 2020 8:37 am
Forum: 8-bit acorn hardware
Topic: BBC Master needs repair please help
Replies: 3
Views: 425

Re: BBC Master needs repair please help

Maybe there's a problem with bit 3 of the NVRAM chip's memory?
by stephen_usher
Mon Apr 27, 2020 8:52 pm
Forum: general
Topic: Today I received.....
Replies: 6058
Views: 641290

Re: Today I received.....

Lardo Boffin wrote:
Mon Apr 27, 2020 4:39 pm
jonb wrote:
Mon Apr 27, 2020 4:35 pm
Is that an Issue 1? Grey keys and all that...
Yes. Serial number 862 so pretty early!

If Wikipedia is to be believed then it is number 862 of about 5,000,000.


904C2841-2B3A-4636-AF2B-503ED6544444.jpeg
Don't you love those hand-drawn tracks?!
by stephen_usher
Fri Apr 03, 2020 12:59 pm
Forum: off-topic
Topic: Which retro calculator is best?
Replies: 29
Views: 1858

Re: Which retro calculator is best?

My Casio fx-2500 (bought February 1979) got me through my 'O' Levels and still works nicely.
IMG_0903.jpg
by stephen_usher
Thu Mar 26, 2020 4:01 pm
Forum: general
Topic: Today I received.....
Replies: 6058
Views: 641290

Re: Today I received.....

I think a lot of these will be arriving today... ZX Spectrum Next accelerated... Nice :-) I would have like one, but I missed the boat on the Kickstarter. I am a backer of the Atari VCS console though, but don't know when that's likely to arrive. Second Kickstarter will hopefully start directly aft...
by stephen_usher
Thu Mar 26, 2020 1:44 pm
Forum: general
Topic: Today I received.....
Replies: 6058
Views: 641290

Re: Today I received.....

I think a lot of these will be arriving today... ZX Spectrum Next accelerated...
IMG_1827.jpg
by stephen_usher
Fri Mar 20, 2020 6:46 pm
Forum: 32-bit acorn hardware
Topic: Today I overclocked my A3010
Replies: 442
Views: 49435

Re: Today I overclocked my A3010

My goodness! Looks good.
by stephen_usher
Sat Mar 14, 2020 11:18 am
Forum: 32-bit acorn hardware
Topic: Today I overclocked my A3010
Replies: 442
Views: 49435

Re: Today I overclocked my A3010

That's still cool enough to keep your finger on it without getting uncomfortable. Maybe no-one else has measure the temperature.

Anyway, I was being cautious, given that there are no replacements available.

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