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Display bandsHi all, I'm busy working on an issue 3 16k Spectrum I picked up on eBay. I've upped it to 48k and put a new membrane in. I noticed the display was…
... was a problem with the oscillator that produces the colour frequency ... -
48K colour issuesGentlemen, A friend handed me over a number of 48K machines to service, and among these there are four of them with various flavours of colour iss…
... and TR9 checked, chroma subcarrier oscillator working although with a very ... -
No colour - Issue 2 SpectrumThis one is driving me mad - any suggestions appreciated. I have an issue 2 Spectrum with no colour at all. I found the 12v rail was at just over …
Check X2 (the chroma subcarrier oscillator). If this has failed you'd get no colour.
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Was there a POKE that broke the SpectrumHi Everyone I've been recalling myths and rumours from back in the day. You know "Lunar Jetmans" trailer and that sort of thing. But one rumour …
... ), as the circuits are actually oscillator circuits. So no damage will ... -
Harlequin Rev. G - Composite video problem.What I'm about to describe I'm not experiencing it by myself, so the probable answer to any "have you tested this or that" question is no, I don't, b…
... same, a problem around the AD724 (RGB to CVBS) but do ... -
Harlequin Rev. G - Composite video problem.What I'm about to describe I'm not experiencing it by myself, so the probable answer to any "have you tested this or that" question is no, I don't, b…
... question that poped reading the AD724 datasheet.. If what has happened ... -
A tally on the number of successful builds of the Harlequin[SIZE=4][COLOR=Green][U][B]A tally on the number of successful builds of the Harlequin.[/B][/U][/COLOR][/SIZE] Please post your successes below :-) …
... [/b] SMD parts as the AD724 (video coder), the switching regulator ... -
A tally on the number of successful builds of the Harlequin[SIZE=4][COLOR=Green][U][B]A tally on the number of successful builds of the Harlequin.[/B][/U][/COLOR][/SIZE] Please post your successes below :-) …
Harlequin clone...PCB manufactured!Using Chris Smith's detailed schematics and project notes from the Harlequin... a Speccy fan in the United States by the name of Don (Superfo) has de…
... bad hence considering redoing the AD724. I should have practiced some ...Harlequin clone...PCB manufactured!Using Chris Smith's detailed schematics and project notes from the Harlequin... a Speccy fan in the United States by the name of Don (Superfo) has de…
... if pin 15 of the AD724 is isolated to +5V. The ... a detailed photo of the AD724 and around?
Greetings ...Harlequin clone...PCB manufactured!Using Chris Smith's detailed schematics and project notes from the Harlequin... a Speccy fan in the United States by the name of Don (Superfo) has de…
... if pin 15 of the AD724 is isolated to +5V. The ... a detailed photo of the AD724 and around?
Greetings ... too embarrassed) to show the AD724 up close. If it's ...128 +2 grey, no video but still beepsGot a grey 128 from ebay, im using a 48k spectrum powers supply, all voltages seem ok. I cant get compostie video using the normal mod or from the 8…
... i might try getting an ad724 chip which may be able ...RGB InterfaceSeen a few of these on eBay recently, are there any modern solutions to RGB on the 48K? Were all busy composite modding, but wouldn't RGB be far bet…
I think the harlequin spectrum could do rgb without the surface mounted ad724 video composite chip.
that would make it cheaper to build. Plus you could pull the z80 from your old speccy. So it would still have the same personality so to speak.Recommend Cassette PlayerI've not needed to buy one for about 30 years so can anyone recommend a new cassette recorder and source please? Do they even make them anymore?
... used to form a "local" oscillator. And another will be used ... the output of the "local" oscillator to produce the intermediate frequency ...So for my first trick...I'm sure people have already used the AD724 or AD725 on other 8 bit machines, and i know the Harlequin uses the 724, but not seen anyone trying to us…
... 74HCU04 from the 17.7MHz oscillator to drive the AD72x with ...So for my first trick...I'm sure people have already used the AD724 or AD725 on other 8 bit machines, and i know the Harlequin uses the 724, but not seen anyone trying to us…
... an independant xtal, but the AD724 is virtually identical (just doesnt ...So for my first trick...I'm sure people have already used the AD724 or AD725 on other 8 bit machines, and i know the Harlequin uses the 724, but not seen anyone trying to us…
... a working TEA2000 by a AD724/5. Both chips have the ...So for my first trick...I'm sure people have already used the AD724 or AD725 on other 8 bit machines, and i know the Harlequin uses the 724, but not seen anyone trying to us…
... a filter. In addition the AD724/725 internally implement a delay ...Small batch of ZX-Unos outside SpainI am a member of the ZX-Uno team. We have launched a sucessfully crowdfunding campaign of 250 ZX-Uno, but they are all sold (mostly in Spain). I apol…
... view of hardware. Because the AD724 has both NTSC and PAL ...Those AY-3-8912X on EbayWas searching Ebay for an AY-3-8912 to use in a small project of mine, and a few questions popped up. What is the version of the 8912 that the 128k a…
... /> Yes, I use a crystal oscillator to drive the PSG. I ...ZX Speccy +2A - B&W & snowy RF output + other issuesHi All, I am new to this forum and I am back to the Spectrum world after 25 years. Recently I've bought a second hand +2A (+2B board - Z70833 Issu…
It's also possible that the UHF oscillator in the modulator is unstable.
[b][i]Mark[/i][/b]So where is the random number in the Speccy ?So I am messing around with ZX Spectrum Assembler and I want a random number. I looked up previous posts and one of the links said that random number…
So where is the random number in the Speccy ?So I am messing around with ZX Spectrum Assembler and I want a random number. I looked up previous posts and one of the links said that random number…
... via a suitable voltage controlled oscillator. Hence both your signal is ...Are there any differencies between Speccies in different countries?I am asking for differencies of ordinary Speccies, not clones. Can I travel to foreign country, buy Speccy from fleamarket and except it will run at …
... the different audio sub-carrier oscillator crystal.Are there any differencies between Speccies in different countries?I am asking for differencies of ordinary Speccies, not clones. Can I travel to foreign country, buy Speccy from fleamarket and except it will run at …
... the different audio sub-carrier oscillator crystal.[/quote]
That is ... ]not[/b] generated by crystall oscillator but by a simple LC ... -oscillator IC38. So, L4 and L5 ...Are there any differencies between Speccies in different countries?I am asking for differencies of ordinary Speccies, not clones. Can I travel to foreign country, buy Speccy from fleamarket and except it will run at …
... ]not[/b] generated by crystall oscillator but by a simple LC ... -oscillator IC38. So, L4 and L5 ...Are there any differencies between Speccies in different countries?I am asking for differencies of ordinary Speccies, not clones. Can I travel to foreign country, buy Speccy from fleamarket and except it will run at …
... the different audio sub-carrier oscillator crystal.[/quote]
Most ...Newly Acquired +3 in the USAI just acquired (rather accidentally, was looking for an empty Spectrum + case!) a pretty nice Spectrum +3, and a US-spec PSU. As far as I can tell …
... the 40056 ULA does. The AD724 would be better fit for ...ZX Speccy +2A - B&W & snowy RF output + other issuesHi All, I am new to this forum and I am back to the Spectrum world after 25 years. Recently I've bought a second hand +2A (+2B board - Z70833 Issu…
... S-Video output using the AD724 or something like it.Spectrum +2 grey RF removalHi everyone. If I were to remove RF output from a +2, just intending to keep Composite video out from TEA2000, then all the components that make t…
Removing those parts should be fine. If you want a really good svideo output, i'd replace the TEA2000 completely with an AD724 or AD725 based circuit.
