stardot.org.uk

SimonSideburns wrote: ↑

Mon Aug 03, 2020 7:16 pm

After that it's pretty much palette switching.

As was the original Amiga boing ball. I think it is ace to see a boing ball pretty much as good as the Amiga's original CES one on a model B

http://amiga.lychesis.net/special/Color ... Boing.html

Ok, tested and seems way better. The -5v rail is now at -4.6v.. What's the margin of error on these? Is this -4.6v with the PSU loaded or unloaded? I think it is unregulated so it changes with the 5v PSU load IIRC. The 12v line does too - that is sub 12v on an unloaded PSU and 13v ish on a fully lo...

A common fault on PSUs is a cracked solder joint or trace. This often happens on capacitors - they move as they heat up and cool down & this movement eventually causes the solder to fracture. First step is a visual inspection of the PCB to look for cracked joints - especially on the filter capacitor...

Yes probably a faulty socket. That's why 1024MAK always says test from chip leg to chip leg where possible.

Did any of the earlier chip replacements help or was it just the CRTC bad traces all along?

I am pretty sure they are TE Connectivity Faston Terminals P/N 62437-1

I got some from Mouser P/N 571-624371

TE do some very similar terminals but using the verniers I think these are the right ones.

I assume I could just solder some wires on the bottom of the motherboard, and that'd fix it? The fix way is just put some wire point to point on the bottom side of the board. If you have lots of time you can hunt the breaks/bad vias down and repair them almost invisibly. It takes some practice. Wir...

Welcome!

Line numbers on 8-bit BBC BASICs are 15bit integers so 0-32767

Try the following and start entering a program...

I find using start address + length an easier syntax...
*SAVE fn 6C00+27B 4285

I think if anyone is to offer more help for your problem you're going to have to post some more code.

Are you doing 2 pass assembly? If so did you set O% & P% inside the FOR loop?

Are you using SWRAM already or targetting an unexpanded model B? One or two banks of SWRAM on a B is pretty common now... Exile style SWRAM support maybe? Conditional compilation to move and cull some assets from the B version with the full play window and assets if you have SWRAM. Do you need all t...

"A Hardware Guide" is quite a desirable book. You might do well splitting that off as a separate sale. TBH You might struggle selling this as a job lot on the forum because most of the regular users will already have the bulk of the hardware they want... they are unlikely to buy the job lot to get 1...

I do recommend having a look at using EEPROMs before considering EPROMs ;-) I think the OP's project is building the EPROM programmer, from the Beebug magazine, so EPROMs are what he needs. I'd have thought that a build at home programmer probably only supports up to 27128. A home built EPROM progr...

You need 27128 or 27C128 for the Model B 16KB ROMs. Many ROMs are 8KB or less, then you can use a 2764. Newer EPROMs are 12.5v program voltage, older are 21v. Many EPROM programmer designs had a switch to choose the voltage. If the one you want to build doesn't have switchable Vpp then add it - it i...

There is a maximum cable length for USB which relates to the propogation speed of the signal down the cables. I can't remember the times off the top of my head. I think for USB2 the spec limit for cable length is 3m long. I don't know what USB 3 is. Some devices might be more robust to being out of ...

It is on the wikipedia list... it is the 16 bit CRC with normal polynomial 0x1021.

IIRC that is the chip that is fabled for needing to be the exact manufacturer & part number Acorn fitted or the beeb wouldn't work. Quite a lot of the timing in a model B is lucky/iffy. I might have some I desoldered but I'd have to check my spares, I think I gave some away to a forum member a while...

You may well have answered your own question with the thread title. Have you checked the sockets? Acorn fitted some fairly poor quality sockets to some revisions of model B which are prone to contacts breaking. edit: You could try wiggling them when you check the continuity in case a fracture is mak...

tricky wrote: ↑

Sun Jul 12, 2020 8:05 am

I don't think I could improve on the gameplay in Snapper and certainly wouldn't please the aficionados.

Are the ghost monster algorithms in Snapper the same as PacMan? I seem to remember reading somewhere they don't follow the same rules.

If you're not fussed then you could just release it license free. You can still retain copyright. That means no-one is allowed to do anything with it. Garbage. You can put something in the public domain if you want to without GPL or BSD license. Just write (c) & released into the public domain will...

If you're not fussed then you could just release it license free. You can still retain copyright.

Have you tried phoning them and speaking to a human? Say it is for repairing pre-2000 era computers and industrial equipment. :) The PB-free Rapid brand solder has the same flux as the 60/40 you're trying to buy. I use if for everything I sell. Wets and flows a little less well than 60/40 but it is ...

Mouser has a TE version. £24 (ouch!)....
https://www.mouser.co.uk/Search/Refine? ... moval+tool

eBay/aliexpress/amazon are worth a search too.

You can do it but you need to use OSCLI to issue a non-constant * command.

OSCLI("LOAD IDX-R "+STR$~I%)

Leaks can be hard to spot. The main sign is that the solder on joints near the caps is matt or dull grey instead of bright and shiny. If you see that they are leaking. If it smells fishy then they are really leaking. You don't get huge amounts of blue/green fur like with a battery leak. As ramtop sa...

They don't leak (amiga) <snip> The leakage problem is notorious on Amiga 600/1200 & various Apple machines but is most often on machines with surface mount electrolytic capacitors. So in the Acorn line up think A3020/A4000 etc. the machines with through hole caps are generally fine. Radials do leak...

There is example code of BASIC overlays in the BASIC ROM User Guide which I think has been made available in PDF on here. I have the dead tree version

What about Spy Hunter? Could also be used as a basis for commando or 1942 (1?). Humm Tricky! I played a lot of Spy Hunter BITD on the BBC so a more authentic port wouldn't seem authentic to me! :lol: 1942 though... there aren't many scrolling shooters on the BBC. Perhaps that would be a good one to...

sydney wrote: ↑

Mon Jun 15, 2020 11:23 am

How did I miss that update? 36MHz? What speed is the cpu rated at?

It is marked as a FN20... what it really is is anyones guess.

Technically yes you could emulate a SID via the 1MHz bus. There is open source SID code out in the wild (apparently not very authentic sounding though). You could emulate various FM chips too. I see the point in connecting a real SID to a a machine or judgebeeb's OPL & synth boards for curiosity val...