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I just saw an announcement on the local BBC news that the RCM is going to be on "Inside Out" East Midlands tonight as they cover the "craze" of collecting old home computers. I'm guessing that the show will appear on the following link sometime after 8:30pm tonight (11th March) for everyone that do...

1. IC76 You need to fit a 74LS163 (BBC B Circuit diagram and others here: http://mdfs.net/Info/Comp/BBC/Circuits/ look for bbc.gif ) Note that the header from the daughterboard may have spread out the contacts making an IC a loose fit. The fix is either to replace the socket, or if you want to avoid...

What's the 40 pin device?
(Edit: Cancel that question - found this https://www.mirrorservice.org/sites/www ... manual.pdf
and it says "Large Scale Integrated Circuit BASF 81041-001")

And have you located a replacement?

I replaced the BNC connector on one of my Beebs with a chassis phono socket. BNC connectors are reserved for test gear and 10base2 as far as I'm concerned. Unhappy memories of numerous broken composite video cables at school, and spending half your lunchtime trying to get a working picture...

Mine kept shutting down about 45 seconds after being powered up. Problem was caused by a botched/leaky battery pack. The battery pack died, and electrolyte from the batteries wicked up the lead and rotted the molex contact. It then continued to rot a track on the PCB. Luckily I could trace where it ...

I've got a CT3990 AWE32 PNP...

Does your scart lead have the required resistors installed?
I'm wondering if the screen is having problems handling the sync signal.

What Roms/utils do I need to get sideways rom/ram working? *ROMS doesn't work for me at all. *SRLOAD doesn't either. I've got a Watford Electronics 12 ROM board with RAM in position 14. Aside: It's also got provision for a solder-on battery. I have no idea what voltage it needs to be (the instructi...

Great, thank you for all the replies - that's really helpful, and I think with a combination of the data sheet, the better photo and a general knowledge of how Ethernet transceivers behave I should be able to get the values right. The extra components look like they're just decoupling for the trans...

More digging. The MX98902 is equivalent to the NS83902. The only thing I can find which uses the NS83902 is an IBM "PPC403GCX Evaluation Board". If you can find the documentation for that board, you might also get a schematic thrown in for free. Details of the HALO FD12-101G magnetics can be found a...

First result after a bit of digging: https://commons.m.wikimedia.org/wiki/File:Acorn_AEH75_Access%2B_A5000_(top).jpg Possibly copied from/originally taken for: http://chrisacorns.computinghistory.org.uk/Network/Pics/Acorn_AEH75_Access+.html Better: http://www.computinghistory.org.uk/det/33963/i-cube...

The ADC socket looks like it's been installed and removed.
It's also got a speech synth upgrade installed - TMS5220 + TMS6100.

What is it? What does it do? Enquiring minds want to know! This enquiring mind also wants to know :lol: No software or documentation as of yet... The TMS320 is a series of digital signal processors. (aka DSP) You've probably bought yourself a programmable audio filter. You'll have fun getting that ...

Hello again! No news 'till today. I replaced the near 6522 but with no result. I unplugged all the eproms except from Basic and OS, i placed a NFS(I tried also a DNFS eprom) eprom, but with no avail. I get the same symptom when i just plug the flat cable. What i am trying to do, is to use a PiTubeD...

I wonder if it would be possible to install this mod internally, by removing R45, R46, R47, connecting the left hand pad (on the schematic, the one connected to the ULA) to the gate inputs, and the outputs to the right hand pad, through some replacement 68R resistors. You would of course need flyin...

1024MAK wrote: ↑

Sun Dec 02, 2018 5:43 pm

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

Mark

Fitting LK4 should add chroma to the video output.

Using *notify I tried to send a message across, but no luck. :? Should this work or is a socket box needed for this setup? Have you got NOTIFY on disk or in ROM? ... It seems I may have the basics wrong. I (probably wrongly) assumed that *notify was an NFS command contained in the NFS rom. *help is...

Have you googled for AM26LS30 which AFAIK is the same part/pin compatible?

Looking at the other side of the pcb it seems there are even more similarities. Looks like someone's brewed copied the original clock PCB, added a track to permanently select one speed and left the link holes undrilled. I love the way the tracks from the transformer secondary pass oh so close to th...

Elminster wrote: ↑

Thu Oct 25, 2018 8:19 am

Could be a crack track or a cold joint, that could cause intermit/self fixing issue.

Or a socketed device being moved microscopically in a tarnished socket by contraction/expansion?

For the through hole Archimedes machines, I designed this a couple of years ago. https://stardot.org.uk/forums/viewtopic.php?f=16&t=10968 It simply, replaces a borked through hole version with a SMT version of the same chip and provides I2C as a breakout. It does depend on the basic functionality o...

A bit like this - http://www.cjemicros.co.uk/micros/individual/newprodpages/prodinfo.php?prodcode=CJE-RTCPOD ?? I was thinking something a bit more generic/"maker"/arduino/RPi-ish. Preferably using a CR2032 (and no charging) or having two pads to connect to an "off board", out of harms way AAA base...

Given the number of A5000's (and others) suffering from battery damage near the RTC chip, wouldn't it make more sense to remove the goosed device from the motherboard and then wire in a "PCF8583+crystal+coin cell battery" on a board. You might even be able to get away with connecting it to the i2c i...

OK... I think I found something. I hooked up my logic analyser to IC30 and I can see the following data on the outputs: That seems to indicate that the 3rd bit is stuck high. The 3rd bit seems to correspond to Q2. Looking at the output of Q2 it starts low, and at power-up it jumps high and just sta...

So the idea is that each diode drops about 0.65Vs? Wouldnt you traditionally use a zenner to clamp the voltage instead? You traditionally use what's in your spares box first. For me, 1N4148 diodes, generic small signal NPN (e.g. BC109, 2N2222 etc), and PNP (e.g. BC179, 2N2907) transistors are all "...

The BBC B library should go to $.LIBRARY The Master library files should go in $.LIBRARY1 If you're copying from an ADFS utilities/fs disc, it's a one for one copy - $.LIBRARY to $.LIBRARY Note that you will have to change the access rights on these files - by default they will probably be WR/, henc...

The "Bad command" is because you don't have the "FS" command in the library directory on the file server. If you were using a Master 128 as a client, you wouldn't see this, because FS is built in to ANFS. The simple fix for all this is to hit return when prompted for the file server number. This has...

You entered 0 for the file server - you should have entered 254.

I would suggest taking the circuit diagram for the Master Econet module, and replacing the ADLC with a bit banging Pi Zero. That would require 3 inputs: clock, data in, "clock present", and two outputs: Data out, and transmit driver enable. There is a lot of circuitry relating to collision detectio...

My Master is going to be the file server. Does it matter what its station number is? Are there reserved numbers that should be used for the file store? I have downloaded a bunch of econet docs but only skim read them so far. Usual practice back in the day was to use station 254 for the 1st file ser...