Search found 259 matches

by johnkenyon
Wed Sep 10, 2014 1:23 am
Forum: 8-bit acorn hardware
Topic: Acorn Econet Bridge ROM
Replies: 12
Views: 2112

Re: Acorn Econet Bridge ROM

I looked on JGH's site before I posted the question. Couldn't find it :roll: Searching for " econet bridge rom " gives the first match as http://mdfs.net/System/ROMs/Econet/ . ;) The source code hasn't been "installed" in the new web server yet. Note to self - merge JGH's source...
by johnkenyon
Tue Sep 09, 2014 5:47 pm
Forum: 8-bit acorn hardware
Topic: Acorn Econet Bridge ROM
Replies: 12
Views: 2112

Re: Acorn Econet Bridge ROM

paulv wrote:Has anyone actually ever imaged this ROM?

Paul
Yes

http://mdfs.net/System/ROMs/Econet/

where you can also find the source code
by johnkenyon
Mon Sep 08, 2014 2:48 pm
Forum: 8-bit acorn hardware
Topic: Beebs and SCSI Hard disks.....
Replies: 74
Views: 16179

Re: Beebs and SCSI Hard disks.....

If you are tempted to try plugging a slightly more modern SCSI drive like the Seagate Hawk 1GB type directly into the Akhter board, be aware of the issue it has with shorting out 0V and +5V on the SCSI connector through the drive. I'll have to check precisely which pin it is when I get home but Bee...
by johnkenyon
Mon Sep 01, 2014 11:06 am
Forum: 8-bit acorn hardware
Topic: Beebs and SCSI Hard disks.....
Replies: 74
Views: 16179

Re: Beebs and SCSI Hard disks.....

The SCSI Parity Enable/Disable option will require a little thought whilst ensuring compatibility with SASI/SCSI1 may best be achieved by 'simply' ensuring that no SCSI-2 commands are used and of course this may not be a trivial exercise. Shirley if the Beeb is acting as an initiator, it will only ...
by johnkenyon
Tue Aug 19, 2014 1:37 pm
Forum: 8-bit acorn hardware
Topic: Worried about my Cub
Replies: 5
Views: 1315

Re: Worried about my Cub

If you want to limit the power going to the VDU (and therefore prevent or limit and damage) when testing it, you could use the trick that TV repair guys use. On the mains voltage side, wire a mains filament light bulb (60W or 100W, try the 60W first) in series with the "line" / "live...
by johnkenyon
Sun Aug 10, 2014 10:26 pm
Forum: 8-bit acorn hardware
Topic: Using a 19V DC laptop PSU on an Electron
Replies: 17
Views: 2573

Re: Using a 19V DC laptop PSU on an Electron

jms2 wrote: When I first plugged the PSU into the mains I'm sure I heard a brief 'crack' noise from inside the plug
That be the spark being drawn as the (mains) plug and socket make contact.
The input capacitor of a switch mode PSU means that the initial current draw is very high for a fraction of a second.
by johnkenyon
Wed Jul 09, 2014 9:37 am
Forum: 8-bit acorn hardware
Topic: Cassette player Motor Control on the beeb
Replies: 6
Views: 1501

Re: Cassette player Motor Control on the beeb

danielj wrote:There's always the possibility that its 5-pin din socket is non standard...

d.
Model I TRS-80's used a 5 pin DIN (with motor control) at the computer end.
These always used a 5pin DIN to 2x3.5mm+1x2.5mm cable.

Have a look at http://www.8bit-micro.com/data-cable.htm
for pinout details.
by johnkenyon
Fri May 30, 2014 10:57 am
Forum: wanted
Topic: Nightingale modem Auto Answer board
Replies: 5
Views: 1293

Re: Nightingale modem Auto Answer board

Has anyone looked at (i.e. disassembled) the software that supports the auto answer board? I'm certain that all that's required is a signal from AA board to userport to say "RING" which goes active when the "bell" is ringing and inactive when it doesn't, and a signal from user po...
by johnkenyon
Thu May 29, 2014 11:04 am
Forum: off-topic
Topic: Anyone know....
Replies: 2
Views: 690

Re: Anyone know....

Where I can get some loose turned pins? Something like the ones in these : http://www.rapidonline.com/cables-connectors/sil-single-in-line-turned-pin-sockets-82700 But without the plastic..... Basically I'm using them as a low profile socket, soldered into a 1.4mm hole but the only way to buy them ...
by johnkenyon
Sat May 24, 2014 6:12 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 9056

Re: Stag PP41 and PP42 programmer

After it has died 1. Is the display still lit ? 2. Is the 5V supply measured on the 6809 still ok ? You will need to power it up with the case opened and the psu/base half folded back. So long as the output voltages are ok I doubt that the psu is the problem. The other possibility is one of the com...
by johnkenyon
Sat May 24, 2014 2:27 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 9056

Re: Stag PP41 and PP42 programmer

You may have discovered a different problem with the regulation of the psu. If you switch the PP42 on with the 42M101 module installed, use "Set 6" and leave it a few minutes does it still lock up ? When I was having problems with my PP42 I checked the 5v output on the psu and it did vary...
by johnkenyon
Wed May 21, 2014 10:14 am
Forum: 8-bit acorn hardware
Topic: retro parallel printer - worth buying?
Replies: 15
Views: 2535

Re: retro parallel printer - worth buying?

CJE Micros has a good selection of ribbons: http://cjemicros.co.uk/micros/prices/categories/ribbons.shtml#ribbons Hah, in some ways nothing has changed then. Compared to the going rate of a second hand dot matrix on ebay some of these ribbons are valued at ten times the cost of the printer they fit...
by johnkenyon
Tue May 20, 2014 5:42 pm
Forum: 8-bit acorn hardware
Topic: teletext adapter
Replies: 15
Views: 2499

Re: teletext adapter

johnha wrote:Hi All,

I have an interest in acquiring an original (unmolested) cheese wedge Teletext adapter, preferably one that was known to work.

If anybody has one they want to part with, please let me know.

John.

I've got one (Coventry/Rugby area, with occasional forays further afield).

/John
by johnkenyon
Fri May 02, 2014 2:52 pm
Forum: 8-bit acorn hardware
Topic: Wierd keyboard thingy
Replies: 10
Views: 2163

Re: Wierd keyboard thingy

I can't budge the 6522s without trashing the legs as I don't have any IC tweezers. Real men use a small plain screwdriver - ease up each side gradually until the IC can be lifted out between thumb and index finger . https://www.youtube.com/watch?v=RkSCh53fO6Y and fast forward to 2:43 onwards. (noti...
by johnkenyon
Fri May 02, 2014 1:44 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 9056

Re: Stag PP41 and PP42 programmer

Well after a few months wait, I finally got a "round tuit", and had a play with my PP42. It looks as if my serial download/upload issues are being caused by the base unit locking up after a random period of time. This was confirmed by powering up without a module inserted. This gives a &qu...
by johnkenyon
Fri Apr 25, 2014 3:42 pm
Forum: 8-bit acorn hardware
Topic: rs423 power drawing how dangerous
Replies: 3
Views: 822

Re: rs423 power drawing how dangerous

for and other project , ft232rl communication with usb-stick and beeb the problem rs432 has no 5 volt power in its socket. how dangerous is it to draw power from lines that are not used from the ds369in ? ic75 chip ?? can it deliver power for the ft232rl chip or will it be broken if usb allso wants...
by johnkenyon
Thu Mar 13, 2014 1:03 am
Forum: 32-bit acorn hardware
Topic: In search of an 8 Volt 100 mA power supply
Replies: 13
Views: 2038

Re: In search of an 8 Volt 100 mA power supply

A 9v supply with two 1N4001 diodes wired in series with the output will give you a shade under 8v.

It's highly likely that your widget is simply dropping the voltage down to 5v with a 7805 regulator anyway...

/John
by johnkenyon
Mon Feb 03, 2014 5:02 pm
Forum: off-topic
Topic: Measuring a co-ax cable
Replies: 2
Views: 679

Re: Measuring a co-ax cable

Totally off topic, but you guys know so much... I have cable TV (well, FIOS TV; that's fiber to the premise, and then an optical network terminator converts to standard coax). The different channels come in on different frequencies, maybe somewhere between 50Mhz and 950Mhz. The cable comes in to th...
by johnkenyon
Fri Jan 17, 2014 10:13 am
Forum: wanted
Topic: 7 Pin DIN BBC PCB mount socket
Replies: 11
Views: 2243

Re: 7 Pin DIN BBC PCB mount socket

If all else fails, fit a 5 pin DIN socket, use a 5 pin DIN lead and live with no motor control...

/John
by johnkenyon
Wed Oct 30, 2013 12:11 am
Forum: off-topic
Topic: Good question....
Replies: 8
Views: 1889

Re: Good question....

CMcDougall wrote:I think the amber/orange ones were worse for 'screen burn'.
Given that the human eye is more sensistive to green light, I reckon a green screen could have the electron gun/wick "turned down" for the same perceived brightness - ergo, less screen burn.

/John
by johnkenyon
Fri Oct 25, 2013 11:57 pm
Forum: 32-bit acorn hardware
Topic: Considering a new kind of battery for A3010
Replies: 15
Views: 2691

Re: Considering a new kind of battery for A3010

They range from probably 800mAh to 2800mAh. I've got some 2500 on my desk. The bigger the capacity, the less well they hold charge. If you use the A3010 on a regular basis, I would recommend using a AAA or AA "low self discharge" NiMH cell - advertised as "Eneloop" or "Good...
by johnkenyon
Fri Oct 25, 2013 5:38 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 9056

Re: Stag PP41 and PP42 programmer

I upgraded from 12.0 to 13.1.

The problems with serial upload (to the programmer) were with 12.0.

I haven't done much playing with 13.1 yet - as soon as I got the thing upgraded to 13.1, the concept of "spare time" became alien to me :(

/John
by johnkenyon
Fri Oct 25, 2013 3:25 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 9056

Re: Stag PP41 and PP42 programmer

The programmer module software has already been successfully upgraded. (it's a 42M101) The initial problem was that I could successfully download (via serial) a file containing a 64k image into RAM using "XXOR" format - aka Motorola Srec. I then used this to program a 27C1001 (mainly to pr...
by johnkenyon
Thu Oct 24, 2013 2:46 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 9056

Re: Stag PP41 and PP42 programmer

Mine has two serial interfaces. I tried upgrading the 101 software into a 27C1001 (rather than a 27C512), and it failed (probably because the image was loaded into the wrong "half" of the device. I then tried creating a 27C1001 file with two copies of the 27C512 image, but I couldn't get i...
by johnkenyon
Fri Sep 20, 2013 7:22 pm
Forum: 8-bit acorn hardware
Topic: ADFS 512 byte sector patch for SASI/SCSI drives
Replies: 54
Views: 6930

Re: ADFS 512 byte sector patch for SASI/SCSI drives

From JG Harston's ADFS 1.50 disassembly (found at http://mdfs.net/Info/Comp/BBC/ADFS/ ) *BYE (at &A103) does: 1) Get current drive from workspace, saves it on the stack 2) If a drive has been selected do a CLOSE #0 3) For drives 3,2,1 and 0 in turn: "Do command &1B - Park Heads" us...
by johnkenyon
Tue Sep 17, 2013 7:32 pm
Forum: 8-bit acorn hardware
Topic: ADFS 512 byte sector patch for SASI/SCSI drives
Replies: 54
Views: 6930

Re: ADFS 512 byte sector patch for SASI/SCSI drives

I feel some research in the depths of the Seagate SCSI manuals comming on to find out just what Stop Unit does.... Without looking at the manual the most likely result of a Stop Unit command will be to spin down the disc and park/lock the heads (if required) for transportation - essential in the da...
by johnkenyon
Thu Sep 12, 2013 10:23 pm
Forum: 8-bit acorn hardware
Topic: OS9/68008
Replies: 16
Views: 2977

Re: OS9/68008

I don't think I've got the right kit to do it on a PC. I know I have a full-length MFM ISA card, and also more than one half-length ones, but I don't have the right sort of PC motherboard to put them in. I can't remember which way round the problem is, but it's either that it's a 16-bit ISA slot in...
by johnkenyon
Wed Sep 11, 2013 5:23 pm
Forum: 8-bit acorn hardware
Topic: Inter WORD EPROM
Replies: 4
Views: 729

Re: Inter WORD EPROM

viewtopic.php?t=6593&p=64380
tells us that it's normal for the pin to be missing...

/John
by johnkenyon
Fri Sep 06, 2013 10:11 am
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 9056

Re: Stag PP41 and PP42 programmer

Thanks for checking,

I don't have any of the PP40 modules, but Matthieu Benoit might appreciate a copy of the software. He runs http://matthieu.benoit.free.fr/ which has documentation (but no software) for the PP40.

John
by johnkenyon
Wed Sep 04, 2013 5:04 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 9056

Stag PP41 and PP42 programmer

Calling all Stag PP41 and PP42 EPROM programmer owners. I'm looking for more recent software software for the modules that came with my (best part of 20yr old) programmer (the base unit software is already at the latest revision) The modules I have are 42M101A (8x32DIP), M111A (8xPLCC), M121A.(8xPLC...

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