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When Amstrad moved all manufacturing for the Spectrum to the Far East with Orion (who did the CPC, PCW and would be doing the soon to be launched PC's), Sugar threw the Timex factory the bone of assembling his DMP2000 printers. By the way, do you know who Amstrad used to assemble the U.K. made vers...

I presume the keyboard fits okay when EPROMs are installed all along the bottom row?

If so, nice design

And a nice find

Mark

Just so you are all aware, only moderators and administrators get the box where a reason can be entered when editing a post. So my recommendation is for members to add a line similar to this at the bottom of their post: Edited due to <reason> You can of course expand on this if you wish. However, if...

OK - you can choose a theme, or style, in the UCP that only shows you the edit line when someone's entered a reason for their edit: new-board-style.png Just so you are all aware, only moderators and administrators get the box where a reason can be entered when editing a post. So my recommendation i...

This forum isn't overrun with trolls The moderator and admin team do their best to keep the forums neat and tidy, so that when the occasional bit of trouble breaks out, it is cleaned up quickly. We are of course helped by members reporting any misbehaviour. So thank you to those members who have ta...

Don't think so...

Mark

I posted about using a light bulb in this post. It includes a diagram

Mark

When you say you checked that IC14 (74LS245 data transceiver), do you mean you tested the chip from the faulty machine in a known good machine AND tried a known good 74LS245 in the faulty machine?

Mark

If you have, or have access to an EPROM programmer, you can program Tricky's test 'ROM', then remove all ROM chips (including the OS ROM) and put the test ROM in the OS ROM socket. This should then show a picture if most of the rest of the 'core' system is functional. Tricky's test ROM does not need...

I guess one persons junk is another’s treasure, certain people in my household think any computer with less than 32 bits is junk. :) Computers with less than 32 bits are a bit rare. A ZX80 has 1024 bits and that's just the RAM... :lol: Mark Don't you mean 8192 bits of RAM? Err, yeah :lol: Been thin...

Click this link to take you to the poll...

Mark

Well done

I'm glad you got the 3.5" drive working.

Mark

On the 'Last edited by' footers, showing a count of edits will discourage me from fixing minor typos. I share the view that a short 'grace period' during which edits can be made invisibly should be allowed, if the forum software is capable of that. That might be a good compromise solution. But I ge...

Elminster wrote: ↑

Sun Jun 17, 2018 12:31 pm

Ditto. I can’t see it either. Didn’t we have this issue the other day? Forget what causes it now.

No, this is a different thing, this time it was due to a mistake made by me.

Mark

Sorry about the image not being visible to most users. I've learnt something new about what can an cannot be done

I've now attached the image to the post in a different way, so now everyone should be able to see it

Mark

Further to my post just above. There exists an auto / quick draft module for this forum software. Another forum that I am a member of uses it. Here is a screenshot of me loading a saved draft:- IMG_7266.JPG Details of the extension are here https://www.phpbb.com/customise/db/extension/auto_drafts/ I...

The diodes do indeed test okay :) The ceramic capacitor realistically cannot be tested properly, as the value of the resistor in parallel (due to the transformer coil having a very low resistance) means the meter will only read the value of the combined resistance in parallel. As the value of the re...

On the subject of composing posts, would members here like the admin team to look into adding an extension to the forum that vastly improves the draft functionality?

Mark

I for one get loads of typo, my brain just read what it thinks it typed. I get pc to read out text on important document and spell check with my ears. I'm fairly good at picking up my own errors when using a normal full sized keyboard and normal monitor on a PC. Especially with the aid of a spell c...

daveejhitchins wrote: ↑

Sun Jun 17, 2018 9:03 am

If it's of any help (?), here's how we did it on our IDE interface:
Which gives Power-on and Drive-activity in one LED (I still have some of these!).

Ahh yes, your cunning design to use a bi-colour two pin LED

Mark

It is indeed likely that the 7406 inverter has failed. But before changing it, keep in mind that this chip has open-collector outputs. That is, it can only drive the output lines low. External pull-up resistors are needed to pull the outputs high. So it is worthwhile confirming that the pull-up resi...

It's a result of the administrators making some 'behind the scenes' changes rather than a result of the upgrade. The reason being to allow better moderation of posts where the rules have been broken, or a poster has said something that is not acceptable. It was thought that this change would be seam...

On an Amstrad NC200... Mark

Measuring resistance, the diodes gave around 1.5-1.8MΩ in one direction and either the same, or up to 8MΩ the other way - but it seemed to fluctuate a lot. With the meter in diode setting there were all consistently 0.5V one way (which is about the voltage drop you'd expect) and, equally expected, ...

My Jiffy bag of bits arrived today (see here).

Thank you fizzyade

Mark

A kit of PCBs and parts for the Acorn Master and Electron cartridge breakout err, 'system' Thank you fizzyade

Mark

My apologies, I forgot that some designs of the Master PSU use four individual diodes (to make a bridge rectifier circuit) instead of having a 'ready made' bridge rectifier :oops: I don't have a Master PSU open, or have any of my own photos. But here is one on Sprow's site: https://goo.gl/images/9t5...

Elminster wrote: ↑

Sat Jun 16, 2018 11:54 am

I guess one persons junk is another’s treasure, certain people in my household think any computer with less than 32 bits is junk.

Computers with less than 32 bits are a bit rare. A ZX80 has 1024 bits and that's just the RAM...

Mark

Fixing an A5000 I have gotten as far as the desktop and the disc drive is now recognised. But it does not work yet. The led is constantly on and I get a “drive empty” error. From the circuit diagram I can’t find a specific signal that drives the drive led: Or is it the Sel2 line that does this? Tha...

Test using the resistance range, not the continuity range. Before proceeding, with the PSU disconnected from the supply, test for voltage across the large 250V electrolytic capacitors. If there is more than 10V, discharge each capacitor. See this post for details. If you don't have a suitable resist...