Search found 9675 matches

by 1024MAK
Mon Apr 06, 2020 8:49 pm
Forum: hardware
Topic: Electron composite poor quality
Replies: 6
Views: 119

Re: Electron composite poor quality

Would a Scart to HDMI adapter improve the quality at all? it's going to a 32" LCD. It depends on how good the SCART RGB to HDMI converter is compare to the TVs SCART RGB analogue to digital converter and signal processing circuitry. If you get a SCART RGB to HDMI converter (and it needs to be a dec...
by 1024MAK
Mon Apr 06, 2020 1:49 pm
Forum: hardware
Topic: Issue 4 Electron - Won't power up
Replies: 44
Views: 913

Re: Issue 4 Electron - Won't power up

See also here...

Mark
by 1024MAK
Mon Apr 06, 2020 12:30 pm
Forum: hardware
Topic: Issue 4 Electron - Won't power up
Replies: 44
Views: 913

Re: Issue 4 Electron - Won't power up

Try here ;-)

Ahh, I get file not found.

I have a copy on my PC. So if someone does not beat me to it, I’ll unload a copy later.

Mark
by 1024MAK
Mon Apr 06, 2020 8:53 am
Forum: hardware
Topic: My Beeb inspection
Replies: 20
Views: 314

Re: My Beeb inspection

I’m going to try the Boobip ERPROM and sideways ram kits as they seem like the least destructive options and are easily removable and I don’t need a degree in electrical engineering haha. I would say good luck, but with Chris’s BooBip modules, you should not need luck :D They are excellent (I have ...
by 1024MAK
Sun Apr 05, 2020 11:30 pm
Forum: off-topic
Topic: Electronics 101 help needed - transitors as a relay
Replies: 4
Views: 138

Re: Electronics 101 help needed - transitors as a relay

What I want to do is make a door magnet remote controllable via an ESP8266. Traditionally I'd use a relay, so the output of a digital pin (eg D7) would be connected to the signal input of the relay, and this would close the circuit and so energise the electromagnet. The electromagnet draws around 4...
by 1024MAK
Sun Apr 05, 2020 12:55 pm
Forum: acorn atom and system
Topic: Atom just acquired not working
Replies: 32
Views: 606

Re: Atom just acquired not working

If you are getting a picture, the 6847 is likely fine. The problem could be the address or data buffers between the 6502 MPU and the video RAM. IC29 (DP8304) is the data bus buffer, IC27 and IC28 (both 81LS95) are the address buffers. And IC30 (74LS138) is the address decoder for the 2114 SRAM chips...
by 1024MAK
Sun Apr 05, 2020 9:48 am
Forum: hardware
Topic: My Beeb inspection
Replies: 20
Views: 314

Re: My Beeb inspection

You can either fit SRAM chips, EPROM, and / or EEPROM chips yourself. And if you want, you can do a small amount of wiring to enable each of the four sockets to be able to access 64K bytes as four 16K byte banks. Or you can buy and plug in modules or expansion boards.

Which route?

Mark
by 1024MAK
Sun Apr 05, 2020 9:34 am
Forum: hardware
Topic: My Beeb inspection
Replies: 20
Views: 314

Re: My Beeb inspection

Before going down the road of expanding/upgrading, I have to ask what you want from the machine? What do you intend using it for? In terms of expanding/upgrading a Beeb, it would also be helpful to know if you have any experience with electronic hardware. The images of many ‘ROMs’ are available on t...
by 1024MAK
Sat Apr 04, 2020 8:41 pm
Forum: other vintage computer hardware, software and games
Topic: Atari 2600 - doesn’t like switching PSUs
Replies: 8
Views: 188

Re: Atari 2600 - doesn’t like switching PSUs

Is it a 1000uF electrolytic cap in the ZX81 PSU? It certainly sounds an easier way forward than the other route! Not always :( There were at least four different suppliers, plus sometimes UK1200 or UK1400 PSUs are found in UK700 cases... Anyway, I’m aware of the following: UK700 with a single 1000u...
by 1024MAK
Sat Apr 04, 2020 5:19 pm
Forum: hardware
Topic: Cub Monitor Question
Replies: 36
Views: 1089

Re: Cub Monitor Question

Which computer cable is this for? DIN connectors normally use numbers for identification of the pins. The insulation of the wires in a cable varies depending on who made the cable. Often for RGB video the red wire is used for the red channel, blue wire for the blue channel, green for the green chann...
by 1024MAK
Sat Apr 04, 2020 4:49 pm
Forum: other vintage computer hardware, software and games
Topic: Atari 2600 - doesn’t like switching PSUs
Replies: 8
Views: 188

Re: Atari 2600 - doesn’t like switching PSUs

In that case, I suspect that there is either a design limitation with the Atari 2600 or a problem with your unit. Is the analogue section of the video circuitry in a screened metal can / box? I suspect noise (‘interference’) from the SMPSU is getting into the video circuitry. You can try to use a fi...
by 1024MAK
Sat Apr 04, 2020 2:53 pm
Forum: hardware
Topic: Issue 4 Electron - Won't power up
Replies: 44
Views: 913

Re: Issue 4 Electron - Won't power up

One of the ‘ROM’ sockets can act as a general purpose ‘ROM’ socket. The ROM does not have to be anything to do with a disk drive interface. Normally it is used for ADFS. The SRAM that has been fitted may be able to be used as a 16K bytes bank of sideways RAM. But you will only be able to access half...
by 1024MAK
Sat Apr 04, 2020 11:54 am
Forum: hardware
Topic: Issue 4 Electron - Won't power up
Replies: 44
Views: 913

Re: Issue 4 Electron - Won't power up

Installing an EPROM in an Acorn Plus 1 If built as standard link positions LK1 and LK2 should have wire links fitted. There should no wire links fitted to LK3 or LK4. A 28 pin 8K byte 2764 (or 27C64) EPROM can just be plugged straight in. You can also use a 16K 27128 (or 27C128) EPROM, but with onl...
by 1024MAK
Sat Apr 04, 2020 11:37 am
Forum: hardware
Topic: Issue 4 Electron - Won't power up
Replies: 44
Views: 913

Re: Issue 4 Electron - Won't power up

If your Plus 1 is standard, link positions LK1 and LK2 should have wire links fitted. There should no wire links fitted to LK3 or LK4. This configuration allows a low capacity 24 pin chip to be used (saving Acorn money). But a higher capacity EPROM can be used. A 28 pin 8K byte 2764 (or 27C64) EPROM...
by 1024MAK
Sat Apr 04, 2020 11:20 am
Forum: upcoming and recent events & exhibitions
Topic: Second 'Virtual ABug', Saturday 11th April, 9am - 5pm
Replies: 30
Views: 506

Re: First 'Virtual ABug', Saturday 11th April, 9am - 5pm

I’ll be lurking and chatting mainly. I won’t be online all day, so will drop in when I can.

Mark
by 1024MAK
Sat Apr 04, 2020 11:10 am
Forum: hardware
Topic: Issue 4 Electron - Won't power up
Replies: 44
Views: 913

Re: Issue 4 Electron - Won't power up

It’s possible to upgrade an AP3 to an AP34 (AP3/4). An AP34 has both ADFS and DFS. See this link for photos of my upgraded AP3 ;-)

Mark
by 1024MAK
Fri Apr 03, 2020 8:32 pm
Forum: hardware
Topic: Issue 4 Electron - Won't power up
Replies: 44
Views: 913

Re: Issue 4 Electron - Won't power up

You can start by upgrading the Plus 1 OS ROM... :wink:

Mark
by 1024MAK
Fri Apr 03, 2020 8:21 pm
Forum: other vintage computer hardware, software and games
Topic: Atari 2600 - doesn’t like switching PSUs
Replies: 8
Views: 188

Re: Atari 2600 - doesn’t like switching PSUs

Traditional mains transformers are an order of magnitude safer than the typical high frequency transformer used in SMPSUs. Even the transformers manufactured for Sinclair (yes, they meet U.K. electrical safety standards). Have you tried a different make/design of modern SMPSU? If the frequency that ...
by 1024MAK
Fri Apr 03, 2020 7:47 pm
Forum: hardware
Topic: Another Elk lives
Replies: 15
Views: 304

Re: Another Elk lives

Electron Power consumption Electron on 12V DC supply: 531mA (6.372W) Electron on 15V DC supply: 415mA (6.225W) Electron on 19V DC supply: 326mA (6.194W) Electron with a Plus 1 on 12V DC supply: 590mA (7.08W) Electron with a Plus 1 on 15V DC supply: 460mA (6.9W) Electron with a Plus 1 on 19V DC supp...
by 1024MAK
Fri Apr 03, 2020 7:21 pm
Forum: hardware
Topic: Another Elk lives
Replies: 15
Views: 304

Re: Another Elk lives

Dave, that leads me to a question - I'm running my Elk/s with a 12V DC 1A power brick. If I were to get a Plus 1, can I still use this power brick or will I need to get an 18VAC one? I’m not Dave, but from the electrical power perspective, adding a Plus 1 increases the current consumption on the +5...
by 1024MAK
Fri Apr 03, 2020 10:57 am
Forum: hardware
Topic: New E2P development
Replies: 23
Views: 830

Re: New E2P development

Aren't HCT quite a bit slower than LS? No. 74LS, 74HC and 74HCT are similar in terms of propagation delay (speed), although there are variations depending on which specific chip is being used. Hence some 74HC chips are slightly faster than the equivalent 74LS part. 74HC and 74HCT are far better at ...
by 1024MAK
Fri Apr 03, 2020 10:46 am
Forum: hardware
Topic: New E2P development
Replies: 23
Views: 830

Re: New E2P development

With any out of production semiconductor part, that appears to be available from trading sites such as eBay, buying is always a gamble. And it does not matter if the person you are buying it from is local in your own country, or elsewhere. If the part has a date code that is within the range of the ...
by 1024MAK
Fri Apr 03, 2020 9:56 am
Forum: acorn atom and system
Topic: Coding question
Replies: 14
Views: 360

Re: Coding question

Any source code that has labels where the value of the label is not known on the first pass, will need the assembler to go through the code a second time. On the second time, now all label values should be know, so the assembler can correctly code forward jumps, branches etc. Hence at one time comme...
by 1024MAK
Thu Apr 02, 2020 1:37 pm
Forum: hardware
Topic: Non booting BBC/B Issue 7 - Continuous beep
Replies: 60
Views: 2259

Re: Non booting BBC/B Issue 7 - Continuous beep

Hello and welcome :D

IC51 is the position for the OS ROM and a ROM with the marking ending with, or including ‘PB04’ is Acorn OS 1.20

Thanks for posting :D

Tell us all about yourself in the introduce yourself topic :wink:

Mark
by 1024MAK
Thu Apr 02, 2020 11:28 am
Forum: upcoming and recent events & exhibitions
Topic: Virtual ABug?
Replies: 22
Views: 1042

Re: Virtual ABug?

Jeremy Thanks for that information and feedback. One question. Who's allowed to attend? Is it just ABUG members or can anyone join in? I'm not really asking for myself, I can't imagine I'd have anything interesting to contribute, but I thought I'd ask in case anyone else wanted to know. The answer t...
by 1024MAK
Thu Apr 02, 2020 7:54 am
Forum: software: other
Topic: ROMs on Turbo MMC
Replies: 12
Views: 393

Re: ROMs on Turbo MMC

Chris ( cmorley ) makes and sells SRAM (static random access memory) modules that just plug into a ‘sideways’ ROM socket in a Beeb. Either PM him (link above) or visit his website www.boobip.com . The product that you want is called ‘ Solderless 32kB Sideways RAM & 32kB ROM ’. I’ve bought various it...
by 1024MAK
Thu Apr 02, 2020 7:39 am
Forum: acorn atom and system
Topic: Replaced spring keys with microswitches.
Replies: 12
Views: 356

Re: Replaced spring keys with microswitches.

The wonders of of 3D printers and what their owners create with them is always amazing =D>

Mark
by 1024MAK
Wed Apr 01, 2020 11:17 pm
Forum: acorn atom and system
Topic: Atom just acquired not working
Replies: 32
Views: 606

Re: Atom just acquired not working

John Ferguson wrote:
Wed Apr 01, 2020 8:58 pm
On cleaning the pins how would go about this as I fear to touch them?
The best tool for this is a fibre glass cleaning pencil.

Mark
by 1024MAK
Tue Mar 31, 2020 8:33 pm
Forum: upcoming and recent events & exhibitions
Topic: Virtual ABug?
Replies: 22
Views: 1042

Re: Virtual ABug?

The person that arranges a Zoom session is the chair and controls the “meeting”. If using a free account, although they say it’s 40 minutes maximum, sometimes they will allow a “meeting” to continue for longer, sometimes up to 60 minutes. If the chair wishes, the system will run automatically, with ...
by 1024MAK
Tue Mar 31, 2020 2:16 pm
Forum: upcoming and recent events & exhibitions
Topic: Virtual ABug?
Replies: 22
Views: 1042

Re: Virtual ABug?

@Mark - That’s good news :D

I’ve just tried Zoom for the first time. It works fine on a tablet. Halfway through our test session (nothing to do with ‘retro’ computing) the service offered us extra time, but keep in mind there was only three of us using it.

Mark