Tag Archives: Circuit

More Oscillations

The Morse Practice Oscillator boards finally arrived! Sometimes I dispair my orders will ever get from China to the UK without incident. I think I may use the DHL option more often. Anyway, having unpacked the new boards, I built … Continue reading

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Oscillator Update

I successfully completed the Twin ‘T’ Oscillator, original by Mike Maynard – K4ICY. It’s a great circuit and sounds really good. Much better than a raspy 555 version. Mike has been kind enough to put a link to my project … Continue reading

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Radio Network

I’ve been a licenced radio amateur since 1993. My callsign is G0TDJ. Morse was always my first love in radio although I have tried many other modes. Recently, ‘Network Radio’ was drawn to my attention by an article in a … Continue reading

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You’re just Multi-faced

A lot has been going on lately so I thought I’d update the blog with some of it. Starting with a small announcement. I secured the domain www.ProjectSPECCY.com It currently re-directs here. I am unsure as yet whether I will … Continue reading

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Refurbishing a 48K Rubber Keyed Sinclair ZX Spectrum – Pt.5 Case Cosmetics

Now the Spectrum’s board was fully refurbed and tested working, it was time to turn my attention to the case, keyboard and fascia. The original fascia looked a little tired and was dented so I had ordered a replacement from … Continue reading

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Refurbishing a 48K Rubber Keyed Sinclair ZX Spectrum – Pt.4 Custom Composite Video Mod

Now I had the Spectrum PCB fully working, I wanted to add a Composite Video modification to round off all the refurbishments. I had already used a neat circuit advised by Andrew Gostling when I repaired a previous machine. Although … Continue reading

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Refurbishing a 48K Rubber Keyed Sinclair ZX Spectrum – Pt.3 Upper RAM Replacement

As I had assertained earlier, the 48K Rubber Key Spectrum I was refurbishing required it’s Upper RAM to be repaired. Since the chips inside of the machine were old, I elected to replace them with a complete Upper RAM Module. … Continue reading

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Diagnosing 48K Spectrum Upper RAM Faults

By way of a break from the refurb posts; I was recently part of a conversation on FaceBook regardig a coulple of 48K Rubber Key Sinclair Spectrums. Both were proved to have faulty Upper RAM problems by issuing the command … Continue reading

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Refurbishing a 48K Rubber Keyed Sinclair ZX Spectrum – Pt.2 Replacing the Regulator

The poor 7805 in any Sinclair Spectrum always works really hard. It was probably the best solution when the machine was designed but things have moved on. Switch-mode technology has improved and reduced in size. Therefore, when refurbishing any Sinclair … Continue reading

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EPROM Info Table

One of the other things I am involved in is graphics. I have had this table knocking about on my hard drive for a while: It’s available from several sources and I find it very useful. Search as I might, … Continue reading

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