Search found 168 matches

by johnkenyon
Tue Sep 25, 2018 1:59 am
Forum: hardware
Topic: New econet setup
Replies: 48
Views: 732

Re: New econet setup

You entered 0 for the file server - you should have entered 254.
by johnkenyon
Wed Sep 19, 2018 2:37 pm
Forum: hardware
Topic: New hardware suggestion - Pi econet server
Replies: 33
Views: 900

Re: New hardware suggestion - Pi econet server

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...
by johnkenyon
Tue Sep 18, 2018 6:12 pm
Forum: hardware
Topic: New econet setup
Replies: 48
Views: 732

Re: New econet setup

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...
by johnkenyon
Mon Sep 17, 2018 10:42 am
Forum: hardware
Topic: New hardware suggestion - Pi econet server
Replies: 33
Views: 900

Re: New hardware suggestion - Pi econet server

Following the famous phrase ‘if in doubt add another Pi’ could you put a Pi zero in a box with level shifters etc. and an econet connecter and use this purely to bit bang? It would take in raw econet data and convert it to something that the Pi server could use. It would also take meaningful data f...
by johnkenyon
Fri Sep 07, 2018 12:07 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1083
Views: 97012

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Quick question - is the serial debugging linux based? Call me mad but I have this idea to use a 3B+ for the co-pro and also stick a ZeroW in there (maybe a Zero and a Zero W?), all powered by the master and just SSH to the 0W for debugging sessions. I guess it would make sense to mount a double pol...
by johnkenyon
Thu Sep 06, 2018 10:40 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1083
Views: 97012

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Received my PiTubeDirect(s) yesterday and am really happy with them so far, thanks to everybody involved for making this happen. I have one simple question/concern - when I set up the cmdline file so that it defaults to the copro on (at 0 say), it cold starts fine, without needing to press break or...
by johnkenyon
Sat Aug 25, 2018 6:42 pm
Forum: hardware
Topic: New A3000 4MB memory
Replies: 39
Views: 1037

Re: New A3000 4MB memory

Are any 72pin SIMMs electrically compatible? Fast Page Mode (FPM) should be. Since the A3000 doesn't interleve memory banks EDO _might_ work in it too. I have some EDO I might try it on a board just for kicks. The reason I asked was because I've got a load of 72pin 4Mb SIMMs sat in a box and this l...
by johnkenyon
Sat Aug 25, 2018 1:10 pm
Forum: hardware
Topic: New A3000 4MB memory
Replies: 39
Views: 1037

Re: New A3000 4MB memory

Are any 72pin SIMMs electrically compatible?

/John
by johnkenyon
Fri Aug 24, 2018 5:27 pm
Forum: other vintage computer hardware, software and games
Topic: Caution: Latest TL866A/CS firmware can brick programmer
Replies: 28
Views: 700

Re: Caution: Latest TL866A/CS firmware can brick programmer

His videos have a lot of NSFW language. Swearing and some racist/sexist outbursts. The forum is pretty much the same. Just in case anyone is browsing from work like I do sometimes. I've watched a few of his video blogs and he seems to be a bit loud/gobby, and not particularly funny which puts me of...
by johnkenyon
Fri Aug 24, 2018 11:25 am
Forum: other vintage computer hardware, software and games
Topic: Caution: Latest TL866A/CS firmware can brick programmer
Replies: 28
Views: 700

Re: Caution: Latest TL866A/CS firmware can brick programmer

kuro68k wrote:
Thu Aug 23, 2018 2:31 pm
Thanks for that, I'll avoid upgrading.

Direct link to the download: https://www.dropbox.com/s/330bs8t4uucnyi9/TL866.zip

EEVBlog is NSFW and the owner has been known to dox people, so better to avoid it and use the direct link if you can.
Never seen any NSFW stuff on the forums.

/John
by johnkenyon
Thu Aug 23, 2018 7:45 am
Forum: hardware
Topic: AND01 troubles
Replies: 35
Views: 755

Re: AND01 troubles

Back in the day I had a summer job working at a Acorn approved dealer. One of my common tasks was to replace the factory fitted WD1772 with a WD1770 because older drives couldn't handle the 1772's faster stepping rates.
by johnkenyon
Thu Aug 02, 2018 4:02 pm
Forum: hardware
Topic: Amstrad Gt64/65 Monitors
Replies: 12
Views: 319

Re: Amstrad Gt64/65 Monitors

I seem to recall that the composite out of the bbc could be fed to both the luminance and sync pins to get a picture on these or am I wrong? It works, but it's not great. Not a lot of adjustment, the pictures is with the lowest brightness set on the monitor. It's difficult to get a black background...
by johnkenyon
Fri Jul 20, 2018 5:24 pm
Forum: general
Topic: *TAPE baud rates
Replies: 24
Views: 658

Re: *TAPE baud rates

The answer might be here: https://en.wikipedia.org/wiki/Kansas_City_standard The BBC tape interface is based on CUTS, and 300bd is the lowest common denominator. I don't know if 300baud was more reliable or not - by the time I was hacking around on BBC's my stuff was either stored on the college's L...
by johnkenyon
Fri Jul 20, 2018 5:15 pm
Forum: hardware
Topic: BBC Micro Serial ULA
Replies: 7
Views: 226

Re: BBC Micro Serial ULA

Have you tried Mark Haysman (Retroclinic)? He might well have a drawer full of serial ULAs rescued from dead boards. Mark was selling Compact serial upgrade kits on eBay so might well have some. Looking at the Master Compact circuit diagram, the only bits of the serial ULA used are the baud rate ge...
by johnkenyon
Fri Jul 20, 2018 2:04 pm
Forum: hardware
Topic: BBC Micro Serial ULA
Replies: 7
Views: 226

Re: BBC Micro Serial ULA

Has anyone reverse-engineered the serial ULA (2C199E / VC2026)? I seem to be getting a lot of machines lately with defective chips. In most cases this keeps the cassette motor turned on at all times, with pin 11 remaining high. As far as I can see, the only way to get replacements these days is to ...
by johnkenyon
Fri Jul 13, 2018 5:00 pm
Forum: hardware
Topic: Cheap web-modem for the beeb/master (and arc if ya like!)
Replies: 106
Views: 3768

Re: Cheap web-modem for the beeb/master (and arc if ya like!)

OK, I've been keeping this one to myself for too long. I've posted an annotated disassembly of the Commstar 1.40 ROM at https://stardot.org.uk/forums/viewtopic.php?f=32&t=15377 If someone wants to provide me with the strings you need to send, I'm willing to either hack together a version which will ...
by johnkenyon
Fri Jul 13, 2018 4:51 pm
Forum: archive submissions
Topic: Commstar 1.40 disassembly
Replies: 0
Views: 223

Commstar 1.40 disassembly

Here's my annotated disassembly of Commstar 1.40 Note that it's written to be assembled using the xa 6502/RC65C02/68516 cross-assembler. For the uninitiated, this means: 1) $FF not &FF for hex 2) % indicates binary (used once) 3) ROR replaces ROR A, ROL replaces ROL A, and ASL replaces ASL A To asse...
by johnkenyon
Fri Jul 13, 2018 4:31 pm
Forum: hardware
Topic: Cheap web-modem for the beeb/master (and arc if ya like!)
Replies: 106
Views: 3768

Re: Cheap web-modem for the beeb/master (and arc if ya like!)

Use commstar version 1.4. Once connected change from terminal to viewdata mode and ensure you press I and change the speeds back to 2400 before pressing C to enter chat mode again (ie connect to the modem). Commstar 2 won't work. Why don't you patch Commstar so that it starts in 2400 baud mode for ...
by johnkenyon
Thu Jun 28, 2018 10:57 pm
Forum: hardware
Topic: bbc b version finding
Replies: 3
Views: 204

Re: bbc b version finding

Note that the board issue does not tell you if it's a model A or a model B. Mark The absence of most interface connectors on the back (beyond cassette, RGB, video and RF) is usually a good indicator of a Model A, as is a missing user VIA+all underside IDC connectors. The absence of an Econet connec...
by johnkenyon
Mon Jun 18, 2018 11:33 am
Forum: hardware
Topic: Master PSU repair - not going well
Replies: 14
Views: 536

Re: Master PSU repair - not going well

If you are dealing with a short and want to probe around with the supply connected and without fuses popping, then use a lightbulb current limiter aka "the light bulb in series with load". Take one mains socket (preferably switched), a batten lightbulb holder, a length of 3 core mains flex and a plu...
by johnkenyon
Fri Jun 08, 2018 6:19 pm
Forum: hardware
Topic: Cassette player maintenance
Replies: 14
Views: 314

Re: Cassette player maintenance

Many years ago I worked for a company which, amongst other things used to service cassette player modules used in TOA BA-410 background music systems. These had 1 to 4 tape modules in a 19" case, and they played crappy background music in posh food pubs that didn't want a jukebox back in the 1980s. ...
by johnkenyon
Fri Jun 08, 2018 9:17 am
Forum: hardware
Topic: Early BBC Micro's (ICL)
Replies: 9
Views: 644

Re: Early BBC Micro's (ICL)

Here's my issue 2 model A, Cleartone manufactured, serial 100403 and all chips socketted which is very nice :) It's in great condition, so I don't want to modify (other than easily reversible) but it is rather limited without any ports...! I'm currently working up a reliable and reversible fitment ...
by johnkenyon
Thu Jun 07, 2018 3:38 pm
Forum: hardware
Topic: ECONET WOES
Replies: 70
Views: 3545

Re: ECONET WOES

Thanks John, means nothing to me though, I don’t do networks - I was just trying to help Darren with the question... :lol: One point of clarification, you said OSWORD &14 but the RTC call RAMagic supports is OSWORD 14 (decimal) or &0E. Maybe you meant &14 because that’s an NFS functions call but it...
by johnkenyon
Thu Jun 07, 2018 2:01 pm
Forum: hardware
Topic: ECONET WOES
Replies: 70
Views: 3545

Re: ECONET WOES

I could be completely wrong here but I don't think you can 'remotely read' the RTC dongle from a station, not a lot (as I have understood anyway) is known about it really. Darren doesn’t have a User Port RTC dongle, he has one of my RAMagic units which, amongst other things, includes a sideways rom...
by johnkenyon
Mon Jun 04, 2018 4:14 pm
Forum: hardware
Topic: Cheap web-modem for the beeb/master (and arc if ya like!)
Replies: 106
Views: 3768

Re: Cheap web-modem for the beeb/master (and arc if ya like!)

Just a thought of mine will look at this weekend unless anyone else has? Just pure laziness but has anyone moded the commstar Rom image to default the send and receive and parity options to N81 9600 ? Just saves the time! I’ve moded Daniels Sketch to add a ATMYFI command that adds in my ssid etc an...
by johnkenyon
Tue May 22, 2018 9:00 am
Forum: wanted
Topic: Wanted Prestel Adapter
Replies: 7
Views: 456

Re: Wanted Prestel Adapter

That is a very kind offer, I have sent a message to John Kenyon in the hope of purchasing his, however, if for any reason that doesn't work out, I may take you up on your offer. I am particularly interested in the signalling that occurs on the RTS/CTS lines for dialling and call set up etc. The Aco...
by johnkenyon
Sun May 20, 2018 11:39 am
Forum: wanted
Topic: Wanted Prestel Adapter
Replies: 7
Views: 456

Re: Wanted Prestel Adapter

I have one - PM me with an offer (letting me know your location), noting that I won't be able to ship it for at least a fortnight.

/John
by johnkenyon
Thu May 03, 2018 11:16 pm
Forum: hardware
Topic: TEAC FD55V floppy phototransistor
Replies: 8
Views: 371

Re: TEAC FD55V floppy phototransistor

Any chance of some dimensions?
Outside diameter
Depth (base to start of dome)
Depth (base to tip of dome)
The electrical characteristics of a replacement device are probably secondary to how big the thing is.
/john
by johnkenyon
Thu May 03, 2018 8:26 pm
Forum: hardware
Topic: EPROM programmer
Replies: 18
Views: 981

Re: EPROM programmer

1024MAK wrote: [Some units don't prevent the UV light from escaping, so if light does leak out, don't look at the light!!!
But it's so beautiful...
(I'll get my coat)
by johnkenyon
Thu Apr 19, 2018 6:06 pm
Forum: hardware
Topic: SWRAM protection at power down
Replies: 8
Views: 622

Re: SWRAM protection at power down

The back in the day solution would be to copy the ATPL Sidewise board had a brown out protection circuit which prevented spurious RAM writes. A look at page 6 the battery backup installation manual may help: http://8bs.com/othrdnld/manuals/hardware/ATPLBatteryBackup_pdf.zip This did a pull down on o...