Search found 6977 matches

by 1024MAK
Sat Feb 17, 2018 11:58 pm
Forum: stardot.org.uk
Topic: Stardot logo fixed and now spud and banana free!
Replies: 57
Views: 879

Re: Stardot logo infected with spuds!

Ahh, yessir, the correct StarDot logo is back :D =D> 8)

Mark
by 1024MAK
Sat Feb 17, 2018 11:09 pm
Forum: general
Topic: little optimistic???
Replies: 19
Views: 612

Re: little optimistic???

Some of the chips available on eBay are actually pulled chips from existing equipment. From just looking at it, it's hard to tell if someone has put a modern chip in a form that looks like an older existing DIL chip. The main problem is that some existing chips are being remarked,having their pins r...
by 1024MAK
Sat Feb 17, 2018 11:01 pm
Forum: general
Topic: little optimistic???
Replies: 19
Views: 612

Re: little optimistic???

The price of 1980s and 1990s computers may be high and still going up at the moment. But as time goes on, it is possible that the demand may wane. After all, most people who missed them when at school are not likely to be very interested in them. And some of those people who are buying them to recre...
by 1024MAK
Sat Feb 17, 2018 10:45 pm
Forum: other vintage computer hardware, software and games
Topic: Finding a short circuit
Replies: 5
Views: 126

Re: Finding a short circuit

EPROMs often don't survive being put in the wrong way round if power has been applied... It's not unknown for people who don't know what they are doing to incorrectly insert chips. I bought some ZX81s once that apparently came from a college. Apart from the usual broken keyboard membranes, a lot of ...
by 1024MAK
Sat Feb 17, 2018 5:34 pm
Forum: other vintage computer hardware, software and games
Topic: Finding a short circuit
Replies: 5
Views: 126

Re: Finding a short circuit

Yep, you can do that. If you have access to a thermal infra red camera, that would pinpoint any hot components. Failing that, it's the finger tip test :mrgreen: Does the board have any tantalum capacitors? These are known to fail short circuit. Ceramic capacitors if physically damaged can also go sh...
by 1024MAK
Sat Feb 17, 2018 5:20 pm
Forum: general
Topic: little optimistic???
Replies: 19
Views: 612

Re: little optimistic???

Well, if the current production CMOS 65C02 CPUs and 6522 chips last as long as the older NMOS parts, it is certainly possible...

In the industry where I work, we maintain electrical equipment that was designed in the 1960s, 1970s and 1980s...

Mark
by 1024MAK
Sat Feb 17, 2018 7:30 am
Forum: general
Topic: Today I received.....
Replies: 4430
Views: 274503

Re: Today I received.....

richardtoohey wrote:So have you got a ... chip ... on your shoulder?

Just Mr Potato Head :lol:

Mark
by 1024MAK
Sat Feb 17, 2018 5:41 am
Forum: general
Topic: Today I received.....
Replies: 4430
Views: 274503

Re: Today I received.....

http://stardot.org.uk/forums/download/file.php?mode=view&id=35517&sid=1fc129335089dbda4a22ebf2fdbc5668 http://stardot.org.uk/forums/download/file.php?mode=view&id=35517&sid=1fc129335089dbda4a22ebf2fdbc5668 IMG_6502.PNG http://stardot.org.uk/forums/download/file.php?mode=view&id=...
by 1024MAK
Fri Feb 16, 2018 10:16 pm
Forum: stardot.org.uk
Topic: Stardot logo fixed and now spud and banana free!
Replies: 57
Views: 879

Re: Stardot logo disappeared!

Maybe we should switch emulators to one that matches the new logo?
Like this emulator...

Mark
by 1024MAK
Thu Feb 15, 2018 5:18 pm
Forum: stardot.org.uk
Topic: Stardot logo fixed and now spud and banana free!
Replies: 57
Views: 879

Re: Stardot logo disappeared!

A minor point, but in the "compact" view of the forum that I get when I view it in portrait orientation on my phone, there aren't any text labels next to the Notifications and Messages icons, and the icons themselves (the bell and the envelope) aren't clickable, so I have to turn the phon...
by 1024MAK
Wed Feb 14, 2018 12:22 am
Forum: community projects
Topic: Earliest examples of each machine?
Replies: 30
Views: 2487

Re: Earliest examples of each machine?

I NEED TO SEE AN ISSUE 1!!! :evil: Sorry about the outburst :oops: But I need to see one with my actual eyes :shock: Lee You may will have to wait a while long time, they are rather rare. Some say that not many escaped into the wild. Others say that they were recalled. It's also possible that only ...
by 1024MAK
Sun Feb 11, 2018 4:03 pm
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2510
Views: 195088

Re: Worth Taking a Look At

As per usual, it was a reasonable price until the last moments (just three bids when I looked), when it went mad!

Mark
by 1024MAK
Sat Feb 10, 2018 6:56 pm
Forum: other vintage computer hardware, software and games
Topic: Solutions for a sheered screw
Replies: 11
Views: 197

Re: Solutions for a sheered screw

Or, replace or extend the Earth wire, and attach it at the other end of the case...

Mark
by 1024MAK
Sat Feb 10, 2018 6:54 pm
Forum: other vintage computer hardware, software and games
Topic: Solutions for a sheered screw
Replies: 11
Views: 197

Re: Solutions for a sheered screw

Drill it out.
Countersink the outside.
Fit a suitable machine screw with star washer, then nut.
Fill in the head of the machine screw with filler.
Paint over it :wink:

Mark
by 1024MAK
Sat Feb 10, 2018 11:56 am
Forum: hardware
Topic: BBC micro black linear PSU repair
Replies: 12
Views: 277

Re: BBC micro black linear PSU repair

daveejhitchins wrote:Has anyone mentioned changing all the Tantalums?

Dave H :D

Martin talks about the Tantalums in his article. It is also mentioned in the linked to thread.

If during testing, problems are found, then yes, it may well be worthwhile changing them.

Mark
by 1024MAK
Sat Feb 10, 2018 1:46 am
Forum: hardware
Topic: BBC micro black linear PSU repair
Replies: 12
Views: 277

Re: BBC micro black linear PSU repair

Steve, the pictures, text and schematic in Martin Jones's article are consistent with there being TWO 4700uF electrolytic capacitors. It looks like there is one on the underside (track) side of the PCB as well as one on the top of the board. But your board does not have a 4700uF electrolytic capacit...
by 1024MAK
Sat Feb 10, 2018 1:28 am
Forum: hardware
Topic: BBC micro black linear PSU repair
Replies: 12
Views: 277

Re: BBC micro black linear PSU repair

Does anyone know if Acorn kept the 3 sections of the later issues main bbc boards isolated? If not then you shouldn't use the linear psu with a later board. At some stage, on one of the later issue boards, Acorn connected all three +5V power points together via the PCB tracks. This applies to the i...
by 1024MAK
Sat Feb 10, 2018 1:04 am
Forum: hardware
Topic: BBC micro black linear PSU repair
Replies: 12
Views: 277

Re: BBC micro black linear PSU repair

Conventional PSU Testing Suggested steps: ⋅ Check the mains plug (including the plug fuse), the cord (cable) and the PSU's T400mA fuse (T meaning Time-delay, also known as slow blow or anti-surge). ⋅ Using a multimeter, test on resistance across the switch. Then test the whole m...
by 1024MAK
Fri Feb 09, 2018 7:38 pm
Forum: for sale / freebies
Topic: New TEAC floppy drives
Replies: 39
Views: 2638

Re: New TEAC floppy drives

Wow! There was seven before I placed my order earlier...

Mark
by 1024MAK
Fri Feb 09, 2018 7:36 pm
Forum: hardware
Topic: BBC Master noob
Replies: 48
Views: 1109

Re: BBC Master noob

Once the CMOS SRAM within the RTC chip has been "configured", the Master will be fully functional. The only thing the battery does, is supply power when mains power is not present (i.e. switched off) so that the SRAM can retain the settings. The Master ROM chip contains the OS plus a numbe...
by 1024MAK
Fri Feb 09, 2018 6:21 pm
Forum: hardware
Topic: BBC Master noob
Replies: 48
Views: 1109

Re: BBC Master noob

No. But if you added the appropriate circuitry, any rechargeable battery technology could be used.
However, it's not really worthwhile getting too carried away.

It is also possible to use 3V coin cells with a diode and an appropriate value resistor.

Mark
by 1024MAK
Fri Feb 09, 2018 4:27 pm
Forum: hardware
Topic: BBC Master noob
Replies: 48
Views: 1109

Re: BBC Master noob

Looking at the old cells taken out they were not rechargeable. However there are no additional components present in the case to stop this. :? Any "non-rechargeable" battery pack for a Master will have a diode and a resistor, as the connector on the Master motherboard is a straight feed o...
by 1024MAK
Thu Feb 08, 2018 11:31 pm
Forum: hardware
Topic: Kempston Competition Pro
Replies: 12
Views: 255

Re: Kempston Competition Pro

I posted a simple Joystick tester schematic over on World of Spectrum a wee while ago ;-) That may help.

Mark
by 1024MAK
Thu Feb 08, 2018 11:21 pm
Forum: hardware
Topic: Kempston Competition Pro
Replies: 12
Views: 255

Re: Kempston Competition Pro

Does it have a 9 pin D connector, or a user port IDC connector?

Mark
by 1024MAK
Thu Feb 08, 2018 9:37 pm
Forum: other vintage computer hardware, software and games
Topic: Apple II Super Serial Card Rebuild
Replies: 19
Views: 406

Re: Schematic notation...

vanekp wrote:---><--- are normally connected and can be cut in the middle to break the jumper/track.
and ---ꓷD--- are open tracks where you can put a blob of solder on to make the jumper/track.
Peter.

What Peter said... effectively selection links.

Mark
by 1024MAK
Thu Feb 08, 2018 5:47 pm
Forum: hardware
Topic: BBC Master noob
Replies: 48
Views: 1109

Re: BBC Master noob

Configuring after fitting a new battery pack

Also this Acorn Application note is useful- 203 - Master Series Configuration Guidelines
http://8bs.com/othrdnld/manuals/appnote/AppNote-203.zip or here
http://www.8bs.com/submit/acornappspdf/203.pdf

Mark
by 1024MAK
Thu Feb 08, 2018 5:39 pm
Forum: hardware
Topic: BBC Master noob
Replies: 48
Views: 1109

Re: BBC Master noob

@Lardo Boffin

Flat batteries can cause all kinds of flaming problems...

Various BBC Master manuals including the Welcome Guide are here (bottom of page) ;-)

BBC Master Service Manual

Mark
by 1024MAK
Thu Feb 08, 2018 4:50 pm
Forum: hardware
Topic: BBC Master noob
Replies: 48
Views: 1109

Re: BBC Master noob

danielj wrote:CTRL-F and break will stop it trying to mount a disk.

d.

Until you turn it off, then on again...

You need some new cells...

Mark
by 1024MAK
Thu Feb 08, 2018 3:26 am
Forum: hardware
Topic: Atari joystick interface for BBC Micro?
Replies: 10
Views: 245

Re: Atari joystick interface for BBC Micro?

Here is another thread on the subject Atari joystick on the BBC. This includes an article that has diagrams and text explaining the theory.

Mark
by 1024MAK
Thu Feb 08, 2018 3:15 am
Forum: hardware
Topic: Atari joystick interface for BBC Micro?
Replies: 10
Views: 245

Re: Atari joystick interface for BBC Micro?

The common connection in an Atari (compatible) Joystick is common to all the directional outputs (up, down, left, right) plus the fire button. That is, just to be clear, all the switch contacts use a single common connection. If the Joystick is left in the "home" or "neutral" pos...