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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...

See also here...

Mark

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

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 ...

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...

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...

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

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...

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...

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...

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...

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...

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...

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...

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

Mark

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

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

Mark

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 ...

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...

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...

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 ...

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 ...

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...

Hello and welcome

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

Tell us all about yourself in the introduce yourself topic

Mark

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...

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...

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

Mark

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

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 ...

@Mark - That’s good news

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