Betadisk (original) schematic and pinout 
Monday, August 5, 2013, 12:22 PM
I was searching for a betadisk interface schematic with connector pinouts and found it on World of Spectrum (only).

But I think it's useful putting it online to be found more easily.
So here it is!

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Disciple GAL files 
Tuesday, April 2, 2013, 08:02 PM
It's about time to put the GAL files online for the Disciple disk interface for the ZX Spectrum.

These can be used to replace a defective PAL chip.
PAL chips are obsolete and not all universal programmers are able to program blank PAL chips.
So it's far more easy to use GAL chips which are pincompatible.

Be aware that Disciple defects are often caused by bad soldering contacts!! Resolder all contacts before putting in the effort of swapping the PAL's; that solved the problems with 2 Disciples I had my hands on.

The link to the GAL files is within this World of Spectrum topic.
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Highres Disciple pics 
Saturday, June 9, 2012, 02:43 PM
I posted some highres Disciple photo's on WoS.
Click here for the topic.

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ZX Spectrum 128K composite video fixes in 1 document 
Thursday, January 26, 2012, 08:47 PM
I created a document with video fixes and improvements and video cables for all ZX Spectrum 128K models.

Click here for the document.
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Hires Opus Discovery board pictures 
Thursday, December 1, 2011, 12:38 PM
As I had the rare and awesome opportunity to be able to buy 5 or 6 Opus Discovery interfaces this year, and because I couldn't find hires pics of the board on Google, I thought it was time to upload some myself.

Here's a video in which I'm dissassembling a floppydrive from an Opus because I forgot to set the driveselect correctly:

Here they are pics (click for hires):

Some problems I had to repair with these Opus Discovery interfaces were:
- defective rectifier
- defective ROM
- one didn't have a 6116 ram chip, don't know if it is needed, but I ordered one anyway
- one had a defective WD1770 floppy controller; replaced it with a WD1772 from an Atari ST: another model but pincompatible, and that worked great!
- one floppydrive failed, but luckally that Opus had two! Only needed to make a bracket to cover the space
- the soldered wires on the 'flying' LM317's come off easily with some movement: very frustrating when you are repairing an interface...

I encountered these interesting things:
- two had a rom v2.2 (one even had a paper with rom changes, but I didn't scan it, sorry!); the lowest rom version I found was 2.1, probably the default factory-rom
- I had one large filled floppybox with about 40 floppies filled with data; very rare to have owned as all others had only one or two or no floppies at all
- there are some different ways of how the voltage regulators are mounted
- there are some different board versions, haven't checked for numbers

This seems a lot of trouble, but believe me: ZX Spectrums fail a lot more and at a lot of more parts.

All together the Opus Discovery is a very solid system, which still works after so many years!
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