Search found 7271 matches

by 1024MAK
Sat May 26, 2018 4:06 pm
Forum: off-topic
Topic: Forum GDPR compliance?
Replies: 55
Views: 537

Re: Forum GDPR compliance?

danielj wrote:
Sat May 26, 2018 3:57 pm
Phew - we don't have ads so you're safe whitelisting us :D

d.
Apart from the for sale section.. :lol:
by 1024MAK
Sat May 26, 2018 9:56 am
Forum: stardot.org.uk
Topic: Image sizes
Replies: 18
Views: 133

Re: Image sizes

My thoughts are: I'm concerned at the we're running *very* tight on space at the moment comment from you. You said this before the update/upgrade as well. I presume you mean server HDD space, as opposed to any other possible meaning. Does StarDot have enough space for a reasonable number of back-ups...
by 1024MAK
Fri May 25, 2018 11:27 pm
Forum: hardware
Topic: BBC/Master Power Supply Adjustment
Replies: 11
Views: 239

Re: BBC/Master Power Supply Adjustment

It's very likely that one or more of the electrolytic capacitors are failing.

I'll post more details tomorrow (it's late here).

Mark
by 1024MAK
Fri May 25, 2018 10:45 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG SOUTH 1 to 3 June 2018 (near Camberley)
Replies: 12
Views: 547

Re: ABUG SOUTH 1 to 3 June 2018 (near Camberley)

tricky wrote:
Fri May 25, 2018 5:31 pm
The solder is this type, but there are also some 0.7mm.
Multicore solder.
That's good stuff :D

Mark
by 1024MAK
Fri May 25, 2018 10:38 pm
Forum: hardware
Topic: BBC/Master Power Supply Adjustment
Replies: 11
Views: 239

Re: BBC/Master Power Supply Adjustment

Thanks all for the great advice (as usual) The tolerance of most 5V TTL and compatible chips is at worst, 4.75V to 5.25V. So in practice, you should measure the voltage on the +5V rail at the point on the motherboard that is furthest from the power supply connection point. The voltage here should b...
by 1024MAK
Fri May 25, 2018 10:26 pm
Forum: off-topic
Topic: Forum GDPR compliance?
Replies: 55
Views: 537

Re: Forum GDPR compliance?

Heads up - since the upgrade, I can no longer navigate to any link as a popup appears saying: You cannot access links on this board until you have accepted the Cookie Policy. (The only way I was able to get here was by opening each link in new windows each time). Happy to accept the Cookie Policy b...
by 1024MAK
Fri May 25, 2018 3:13 pm
Forum: off-topic
Topic: Forum GDPR compliance?
Replies: 55
Views: 537

Re: Forum GDPR compliance?

I also suggest that a statement is added to the effect that the text and picture content provided by users to StarDot becomes the copyright of StarDot. This then means that if a user asks for all their posts to be removed, the administrators may not have to remove all of the posts. As removing some...
by 1024MAK
Fri May 25, 2018 11:05 am
Forum: hardware
Topic: BBC/Master Power Supply Adjustment
Replies: 11
Views: 239

Re: BBC/Master Power Supply Adjustment

I wasn't sure if they were susceptible to giving out random voltages, like you hear if you turn an old volume control after many years of disuse. There are about three different types of potentiometers (variable resistor user controls): wirewound, carbon film, "plastic" film. The carbon film type (...
by 1024MAK
Fri May 25, 2018 10:48 am
Forum: hardware
Topic: BBC/Master Power Supply Adjustment
Replies: 11
Views: 239

Re: BBC/Master Power Supply Adjustment

The tolerance of most 5V TTL and compatible chips is at worst, 4.75V to 5.25V. So in practice, you should measure the voltage on the +5V rail at the point on the motherboard that is furthest from the power supply connection point. The voltage here should be at least 4.8V. At the power supply connect...
by 1024MAK
Fri May 25, 2018 10:28 am
Forum: off-topic
Topic: Forum GDPR compliance?
Replies: 55
Views: 537

Re: Forum GDPR compliance?

For organisations that don't sell data, don't provide data for other organisations or companies, don't send out 'marketing' emails, text messages, letters etc, and where they already use an opt-in system, there is not that much to change. As with any new legislation, there is some interpretation, an...
by 1024MAK
Thu May 24, 2018 10:54 am
Forum: hardware
Topic: Testing the serial port
Replies: 3
Views: 121

Re: Testing the serial port

Loop TXD to RXD, and CTS to RTS.
Then use any terminal software program.
I think JGH has a BASIC program somewhere on his site.

If the port is working, the screen should echo everything that you type.

Mark
by 1024MAK
Wed May 23, 2018 9:03 pm
Forum: programming
Topic: Deciphering some BASIC (discovering CommunITel Modem commands)
Replies: 10
Views: 260

Re: Deciphering some BASIC (discovering CommunITel Modem commands)

I don't remember the term "picking-up" from when I worked with MODEMs years ago. I do remember "off-hook" , "answer mode" and "auto-answer"...

Mark
by 1024MAK
Wed May 23, 2018 8:01 pm
Forum: general
Topic: Today I received.....
Replies: 4591
Views: 303194

Re: Today I received.....

I'm outside the area covered by Vigin cable. And was "too close" to the BT exchange for them to install fibre-optic cable... (don't know about now, haven't asked for a while...).

So am on normal broadband. Fast enough for my needs.

Mark
by 1024MAK
Wed May 23, 2018 6:54 pm
Forum: programming
Topic: Deciphering some BASIC (discovering CommunITel Modem commands)
Replies: 10
Views: 260

Re: Deciphering some BASIC

So this is a bit more helpful! flaxcottage has helpfully scanned some documentation that confirms that the modem is speaking 1200/1200 to the beeb no matter what rate it's connected at. Do you mean that the DTE<->DCE speed is fixed, while the line (DCE<->DCE, MODEM to MODEM) speed is controlled by ...
by 1024MAK
Mon May 21, 2018 7:36 pm
Forum: hardware
Topic: Disc rot on 5 1/2” disc
Replies: 9
Views: 292

Re: Disc rot on 5 1/2” disc

<in a wonderful world where new disks are readily available> Discard any jackets that are affected / have the rot. Carefully clean any affected disks. I heard that plain soap helps, but not tried this. Once the disk is clean, allow to dry. Then, once completely dry, put in new jacket. Copy data off ...
by 1024MAK
Mon May 21, 2018 12:12 pm
Forum: hardware
Topic: Disc rot on 5 1/2” disc
Replies: 9
Views: 292

Re: Disc rot on 5 1/2” disc

I strongly recommend that you remove your jacket.
by 1024MAK
Sun May 20, 2018 5:31 pm
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2597
Views: 211907

Re: Worth Taking a Look At

VincentVega wrote:An Acorn System 1:

https://www.ebay.co.uk/itm/Expanded-Aco ... SwkLJbAXde
Well, rather a lot of non-Acorn modules, but still very interesting, I think I'll put a bid in...

Mark
by 1024MAK
Sat May 19, 2018 6:33 pm
Forum: hardware
Topic: Screaming CUB monitors
Replies: 8
Views: 299

Re: Screaming CUB monitors

The horizontal/ line transformer and / or the horizontal defection yoke coil(s) vibrate at the horizontal/ line frequency, which is just within the hearing range of non-decrepit humans... [For system I video, it's 15625Hz]. As we get all old and... our ears become less able to detect the higher "aud...
by 1024MAK
Fri May 18, 2018 10:02 pm
Forum: general
Topic: Today I received.....
Replies: 4591
Views: 303194

Re: Today I received.....

Today's and yesterday's arrivals...
IMG_7112.JPG
Beeb SCSI
IMG_7113.JPG
Beeb SCSI
IMG_7110.JPG
NodeMCU LoLin ESP8266 ESP12E WiFi module
IMG_7109.JPG
6V solar panels
IMG_7106.JPG
gigatron kit
IMG_7107.JPG
gigatron IC's
IMG_7108.JPG
gigatron PCB
Mark
by 1024MAK
Thu May 17, 2018 8:06 am
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2597
Views: 211907

Re: Worth Taking a Look At

Slo wrote:
Lardo Boffin wrote:£134 as it turns out.
:shock: For 12 pages :shock: What's in it future proof fuel formula?
:shock: £11.17p per page :?
by 1024MAK
Thu May 17, 2018 8:04 am
Forum: hardware
Topic: Torch Z80 Problems
Replies: 35
Views: 552

Re: Torch Z80 Problems

Any addresses that are below 0F hex and / or which refer to a/the 8255 (82C55) are Z80 I/O port addresses.
You are looking for the base address of the 6522 VIA in the Tube address range.

Mark
by 1024MAK
Wed May 16, 2018 9:29 pm
Forum: hardware
Topic: Torch Z80 Problems
Replies: 35
Views: 552

Re: Torch Z80 Problems

Hi, Z80, 6522 and 8255 and the ROM are the only socketed chips on this board. Cheers :) I think, if you don't use (maybe have to disable) the Torch ROM in the Beeb, you should be able to adapt a program designed to test the user port 6522 VIA to test the 6522 VIA on the Torch board. You would have ...
by 1024MAK
Wed May 16, 2018 9:24 pm
Forum: hardware
Topic: Torch Z80 Problems
Replies: 35
Views: 552

Re: Torch Z80 Problems

There is no single signal that goes from the Torch board to the Beeb. All communications from the Torch Z80 go via data through the 8255 and 6522 chips.

The Z80 /BUSRQ and /BUSAK system is not used.

Mark
by 1024MAK
Wed May 16, 2018 9:04 pm
Forum: hardware
Topic: Torch Z80 Problems
Replies: 35
Views: 552

Re: Torch Z80 Problems

The link between the two is via the 6522 VIA, controlled via the Beeb's CPU, and the 8255 PIO controlled by the Z80 CPU. The two interface chips (6522 and 8255) have their 'external' I/O pins connected between them. So that the two different CPU's can pass data between themselves. Anything that prev...
by 1024MAK
Wed May 16, 2018 8:16 pm
Forum: hardware
Topic: Torch Z80 Problems
Replies: 35
Views: 552

Re: Torch Z80 Problems

So, it looks like the Torch board is trying to do something, the Z80 CPU is trying to execute a program.

Mark
by 1024MAK
Wed May 16, 2018 3:59 pm
Forum: hardware
Topic: Torch Z80 Problems
Replies: 35
Views: 552

Re: Torch Z80 Problems

If after cleaning the connector pins, you still have problems, then the next step is to remove and refit any/all of the socketed chips on the Torch board. Next up, using your oscilloscope, I suggest the following checks/tests on the CPU. Does the reset pin (Z80 pin 26) go from low to high at power-u...
by 1024MAK
Wed May 16, 2018 3:30 pm
Forum: hardware
Topic: Torch Z80 Problems
Replies: 35
Views: 552

Re: Torch Z80 Problems

Bat wrote:Hi,
Would IPA and a cotton bud be suitable for cleaning?
Cheers :)
Yes if it is general grime or grease.
If the problem is oxidation on connector pins, try using an "ink" eraser. You may need to cut it up...

Mark
by 1024MAK
Wed May 16, 2018 3:11 pm
Forum: hardware
Topic: Torch Z80 Problems
Replies: 35
Views: 552

Re: Torch Z80 Problems

Hi, Guys the start of this thread is someone else, not me! I purchased my Z80 with the ROMs and the guy assures me it all works fine. I have obtained some system discs but haven't tried them as the drive does nothing. From a ROM perspective the only thing I could think of was that it may be incompa...
by 1024MAK
Mon May 14, 2018 9:59 pm
Forum: hardware
Topic: Cheap web-modem for the beeb/master (and arc if ya like!)
Replies: 62
Views: 1877

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

“I love deadlines. I love the whooshing noise they make as they go by.”
― Douglas Adams
by 1024MAK
Mon May 14, 2018 9:27 pm
Forum: hardware
Topic: Cheap web-modem for the beeb/master (and arc if ya like!)
Replies: 62
Views: 1877

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

IMG_7063.JPG
schematic
Files attached.

Thanks to czietz over at Atari-Forum for working out how to use flow control :D =D>
[Details are in this post and one a bit further down]

Mark