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Composite picture qualityI have read many many discussions here about the composite video modification of the Spectrum 16/48K models. I have choosen one of the simplest comp…
[QUOTE=Renegade;790358]LM1889N chip draws how much current?[/QUOTE]
Typically 35mA, max 45mA
[QUOTE=Renegade;790358]A 220uH coil rated for 130mA can be used?[/QUOTE]I don't see why not.
[B][I]Mark[/I][/B] -
Composite picture qualityI have read many many discussions here about the composite video modification of the Spectrum 16/48K models. I have choosen one of the simplest comp…
Datasheet says 35 mA typical, so yes, a 130 mA coil will be fine.
If your coil has a dc resistance over 5 ohms, it might be good to reduce R62 accordingly so that the lm1889 supply voltage does not drop too much.
Tuukka -
48k Spectrum "Jail Bars" Removal?Hi all Just curious I think I saw a post here about the bars that go down the screen on some 48k's I think he referred to them as "jail bars". Any…
... try is Tuukka's 220uH coil mod to filter the LM1889 ... possible that the 220 uH coil can substitute entirely R62 instead ... -
48k Spectrum "Jail Bars" Removal?Hi all Just curious I think I saw a post here about the bars that go down the screen on some 48k's I think he referred to them as "jail bars". Any…
[QUOTE=Falco-F8L;790375]As a matter of fact, it is highly possible that the 220 uH coil can substitute entirely R62 instead of being in series with it.[/QUOTE]
That's very true! Hoping to see the results!
Tuukka -
Faulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
... have no buzz from the coil (sick Spectrums with bad voltage ... they don't make the coil resonate - a Spectrum should have ... joy:
3) Change the Coil and Tr4/Tr5 again.
'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
TR4, TR5, a coil, a power socket, an sr10s05 regulator and some capacitors ordered... exciting! :D48k Spectrum "Jail Bars" Removal?Hi all Just curious I think I saw a post here about the bars that go down the screen on some 48k's I think he referred to them as "jail bars". Any…
... possible that the 220 uH coil can substitute entirely R62 ... R15 with a 220 uH coil. Now I measure 35 ... series with the 220 uH coil. Measurement on C45 goes ... then, that the 220 uH coil does not much.
< ... .
2) The coil dos not lower ripple. Will ...48k Spectrum "Jail Bars" Removal?Hi all Just curious I think I saw a post here about the bars that go down the screen on some 48k's I think he referred to them as "jail bars". Any…
... kHz from the TR4/TR5/coil switching circuit
[*]Various frequencies ... outputs from the TR4/TR5/coil switching circuit would also help ...Spectrum 48k ProblemsHi all Got my 48k today but it's playing up abit... First time i turn it on it was like this: [IMG]http://s26.postimg.org/hlg9d3f3d/IMG_20140830_…
... new board has a quieter coil and also hasa proper Zilog ...48k Spectrum "Jail Bars" Removal?Hi all Just curious I think I saw a post here about the bars that go down the screen on some 48k's I think he referred to them as "jail bars". Any…
For me, the added coil did reduce ripple at LM1889 ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... I install the transistors and coil? There don't appear to ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... be sure.
The coil can only be installed one ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... both, along with the new coil, power socket, capacitor for C47 ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... , a burning smell appeared, the coil buzzing stopped and the speccy ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... circuit (TR4, TR5 and the coil etc.).
Also with ... of TR4, TR5 and the coil. If TR4, TR5 or the ... coil is faulty, the -5V supply ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... line that comes from the coil and goes into the regulators ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... either TR4 died, or the coil died.
It's ...Giving up on SpectrumsHi all... Bit of a downer post here... I'm really close to giving up on Spectrums.. My 48k has given me nothing but head aches since day one... and …
... completely dead... no buzz from coil, no TV output... nothing...
'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... fried upper ram
[*]Power coil likely broken (no noise)
coil, TR4 and TR5, to see ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... 'd hold off on the coil for now, rare enough for ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... 'd hold off on the coil for now, rare enough for ...ZX Spectrum upper RAM module (4532/4164 replacement)Following the [URL="http://zx.zigg.net/LRR/"]lower RAM replacement module[/URL], there have been quite a lot of requests for something similar for th…
... converter fitted and the Speccy coil removed (disabling the Speccy +12v ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... = I can now hear the coil buzzing away when the board ...Short Circuit Damage?Hey Spectrum fans, Currently trying to diagnose what is wrong with my 48K Issue 4B ZX Spectrum. The initial problem was the fact it would not boot -…
... TR4 (along with TR5, the coil and various other bits) generate ...Short Circuit Damage?Hey Spectrum fans, Currently trying to diagnose what is wrong with my 48K Issue 4B ZX Spectrum. The initial problem was the fact it would not boot -…
I always change TR4 and TR5 at the same time, as if one is bad it can take out the other.
The official advice is originally to actually change TR4, TR5 [i]and[/i] the coil, but that may be difficult these days!Smokin... more 48k woesHi, it looks like I've converted another Spectrum 48K+ into a smoke machine. I'd been rebuilding an Opus Discovery unit and everything looked good. …
... by TR4, TR5 and the coil, the voltage on +12V line ...Non-Ferranti ULA 6C001E-7?Hello! I don't like Iss2 boards that much but after revising one Speccy like that for a friend, the results were so positive that I decided to have …
48K Upper memory issues?Having more issues with the 48K spectrum I just fixed that had the black screen in this thread [URL="http://www.worldofspectrum.org/forums/showthread…
... , which I assume is the coil, but that goes away once ...Spectrum Serial Numbers Wanted!![b]This post updated Sept. 26, 2013[/b] As far as I know, the serial numbering system for the Spectrum has never been fully worked out. For the p…
... : A 8-094582 Yellow, Version 6U (8619), 128k +
ULA : Amstrad ...
