Search found 246 matches

by johnkenyon
Fri May 02, 2014 2:52 pm
Forum: 8-bit acorn hardware
Topic: Wierd keyboard thingy
Replies: 10
Views: 1981

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: 8524

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 "Module ?" er...
by johnkenyon
Fri Apr 25, 2014 3:42 pm
Forum: 8-bit acorn hardware
Topic: rs423 power drawing how dangerous
Replies: 3
Views: 734

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: 1802

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: 619

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: 2058

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: 1718

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: 2471

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 "GoodToGo". If you use the com...
by johnkenyon
Fri Oct 25, 2013 5:38 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 8524

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: 8524

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 prove that I...
by johnkenyon
Thu Oct 24, 2013 2:46 pm
Forum: off-topic
Topic: Stag PP41 and PP42 programmer
Replies: 30
Views: 8524

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 it to downl...
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: 6026

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" using control block ...
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: 6026

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: 2696

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: 666

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: 8524

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: 8524

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...
by johnkenyon
Wed Aug 14, 2013 1:31 pm
Forum: 8-bit acorn software: other
Topic: VFS Disassembly
Replies: 12
Views: 2456

Re: VFS Disassembly

Perhaps the VP415 has a different default sector size, which wouldn't be a problem if the drive accepted mode sense (so the computer code could adapt on the fly), or mode select (so the drive could be told what to do).

john
by johnkenyon
Fri Jun 28, 2013 10:29 am
Forum: 8-bit acorn hardware
Topic: Master PSU overhaul.
Replies: 10
Views: 1926

Re: Master PSU overhaul.

The only difference was that the size of the C2 capacitor was different to the originals, so I had to drill a hole through the PSU for it to fit in place properly. There was plenty of room, so it was no big issue. I would have just bent one leg to fit in the hole, taking care not to put any stress ...
by johnkenyon
Fri May 31, 2013 3:56 pm
Forum: general
Topic: Kensington locking a Beeb?
Replies: 8
Views: 1678

Re: Kensington locking a Beeb?

Bin the Kensington lock, buy a plastic coated steel rope with crimped loops at each end which are big enough to let you thread the eyelet at one end through the other. Take the lid off the Beeb, and if neccessary removed the main board to allow you to thread the eyelet though the slot underneath. 1)...
by johnkenyon
Wed Apr 03, 2013 9:57 am
Forum: 8-bit acorn hardware
Topic: A CUB question...
Replies: 26
Views: 2241

Re: A CUB question...

danielj wrote:Just playing with this a bit more... There's no "Thud" as the monitor's turned on - does that mean that the degauss circuit's not actually working?

d.
If it used to "thud" before, then it's a good indication that the degauss is goosed.
by johnkenyon
Tue Apr 02, 2013 5:30 pm
Forum: 8-bit acorn hardware
Topic: A Yank with beebs!! Fun with AC power.
Replies: 29
Views: 4826

Re: A Yank with beebs!! Fun with AC power.

I just dismantled the Master's PSU, and I'm not seeing any links to change. It's an Astec unit, but I don't see any obvious method of changing the input voltage. -Ian http://stardot.org.uk/forums/viewtopic.php?t=5180&p=56894 is your friend. Look under the QC sticker on the top of the board near the...
by johnkenyon
Fri Oct 05, 2012 2:26 pm
Forum: 8-bit acorn hardware
Topic: Odd disk issue
Replies: 5
Views: 1297

Re: Odd disk issue

The head(s) is(are) definitely out of alignment. Next step: find out how to align the heads on whatever model of disc drive you have (noting that Cumana didn't make drives, they just put Chinon/TEAC/whatever drive assemblies into steel/plastic cases) The old school way of doing it was to use a speci...
by johnkenyon
Wed Sep 26, 2012 1:03 pm
Forum: 8-bit acorn hardware
Topic: Strange problem with Valiant Turtle
Replies: 10
Views: 2006

Re: Strange problem with Valiant Turtle

I reckon that this is the part of the circuit in charge of running the motor for the pen. Can anyone identify those round things with pins soldered on? On the schematic they are marked as resistors, but I've never seen a resistor like that before. They show 0.04Ohm on my multimeter. I'm going to re...
by johnkenyon
Tue Aug 28, 2012 12:12 pm
Forum: 32-bit acorn software: other
Topic: SetStation
Replies: 14
Views: 3576

Re: SetStation

Presumably you found this version: http://www.beebmaster.co.uk/downloads/Setstation.rar (Appears to be version 2.00) Does it not work for the A3020? Yes, and no :( - it accepts the station number, but doesn't appear to set it in the CMOS, !Configure shows no change, and nothing's different after a ...
by johnkenyon
Thu Aug 09, 2012 10:24 pm
Forum: 8-bit acorn hardware
Topic: Now the dead B+128K
Replies: 9
Views: 1362

Re: Now the dead B+128K

My money would be on a short-circuit tantalum capacitor somewhere across the 5v rail. Without a B+ board in front of me right now, I can't tell you exactly where to look though... From my experience about 20 years ago, we had a batch of (non-BBC) boards which had resin dipped decoupling capacitors ...
by johnkenyon
Fri Jun 01, 2012 11:44 am
Forum: software & utilities for the pc, mac or unix
Topic: Writing IBM XT floppies on BBC B
Replies: 8
Views: 2869

Re: Writing IBM XT floppies on BBC B

I have vague memories of a Beebug article which either had a program or a ROM which was capable of reading and writing 360k DOS discs.

There's also Sprow's DOSFS : www.sprow.co.uk/bbc/dosfs.htm
by johnkenyon
Sat Apr 14, 2012 6:49 pm
Forum: 8-bit acorn hardware
Topic: Help Power Supply 3.5" Floppy
Replies: 17
Views: 2145

Re: Help Power Supply 3.5" Floppy

Looks like the connector to the drive only supplies +5v to the two outside pins, so assuming it's a 7805 regulator a 9v DC unregulated supply should do the trick. As far as current is concerned, find out what the drive needs (google the drive model number may help). As far as "tip positive or negati...
by johnkenyon
Mon Feb 13, 2012 4:36 pm
Forum: 32-bit acorn hardware
Topic: A5000 CMOS Replacement
Replies: 57
Views: 7657

Re: A5000 CMOS Replacement

Stupid question, but for tidiness, isn't the A5000 RTC circuit (IC, battery, + crystal) a candidate for moving lock stock and barrel to a small separate PCB with 4 wires (+5v, 0v, SDA, SCL) connected somewhere convenient on the PCB?

ISTR that all 4 are present on the podule port...

/John

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