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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…
... I have the upper and lower ram modules installed (in my case ... -
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…
... I have the upper and lower ram modules installed (in my case ... -
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…
Best thing I found for reducing video interference was replacing C5 to C8 (the 12v decoupling caps for the lower RAM) with 1nf ceramics. On mobile at the moment, but if you search my post history you'll find it :)
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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…
... 12v decoupling caps for the lower RAM) with 1nf ceramics. On mobile ... -
Dead issue 3b with black and white barsHi all, I've been donated an issue 3b which has some nice black and white bars with a few flashing blocks. I've done a few RAM tests and could spo…
From the symptoms, I think it's highly likely the CPU is faulty, though I couldn't rule out a RAM (upper or lower) fault. It's very rare for the ZX Spectrum ROM to fail. While you're at it, also check the -5 and 12 V power supply rails at the lower RAM. -
Dead issue 3b with black and white barsHi all, I've been donated an issue 3b which has some nice black and white bars with a few flashing blocks. I've done a few RAM tests and could spo…
... -5 and +12 on the lower RAM, they're all showing 5 ... -
Unresponsive Spectrum with Magenta border.This Spectrum is taking an age for me to repair, thank for all the help thus far! So after I switch on the ZX Spectrum+ I get the familiar white…
Thanks, not what I wanted to hear! :)
However I swappned the ULA to a known good one and it still did the same thing, the ULA in the other rmachine worked fine :)
So I wonder if the lower RAM is still borked? -
Issue 3B turning offI'm trying to save a Spectrum Issue 3B. I restored the power supply section, changing the 7805, TR4, and TR5, besides all electrolytic capacitors. No…
... a faulty chip in the lower ram was putting down the voltage ... already replaced it with a ram module. The stability of the ... -
Opus Discovery "the big switch on" (after 20 years)I have a few of these Opus Discovery's with different Eproms in that have not been swiched for 15-20 years or so . I am in no rush to switch any on …
... a new 48k rom and lower ram chips to try and fix ... is fit twin floppies and ram -
Opus Discovery "the big switch on" (after 20 years)I have a few of these Opus Discovery's with different Eproms in that have not been swiched for 15-20 years or so . I am in no rush to switch any on …
... either a rom or the lower ram gone and the floppy upgrade ... -3 with duel 720k drives, ram and rom
the ... -
Issue 3b boarddiode ID5 and cap C47 are missing from my board will these have any effect on system powering up. I have checked the voltages on the 7508 and its …
... measure the resistance of each RAM IC (you'll need to ... this for the upper and lower RAM chips. If all are ok ... -
Issue 3b boarddiode ID5 and cap C47 are missing from my board will these have any effect on system powering up. I have checked the voltages on the 7508 and its …
... feeling its one of the lower ram chips that is faulty, I ... -
Harlequin Rev GI have just got all the bits to build an Harlequin Rev G system and I went for a red solder mask board. I have fitted the 3 surface mount components…
... the SRAM that forms the "lower" RAM (where the video screen is ... -
Harlequin Rev GI have just got all the bits to build an Harlequin Rev G system and I went for a red solder mask board. I have fitted the 3 surface mount components…
... the SRAM that forms the "lower" RAM (where the video screen is ... -
12V ripple with lower ram installedI repaired a speccy this week. Before doing anything I replaced all caps and measured the transistors in the power section. When doing this I found t…
... this with and without the lower ram installed, same results. Does this ... -
12V ripple with lower ram installedI repaired a speccy this week. Before doing anything I replaced all caps and measured the transistors in the power section. When doing this I found t…
... +12v decoupling capacitors for the lower RAM. These are only 47nf so ... -
12V ripple with lower ram installedI repaired a speccy this week. Before doing anything I replaced all caps and measured the transistors in the power section. When doing this I found t…
... do some changing of the lower ram ic's, it was really ... faulty one, since I got ram error's but it wasn ... -
Issue 4A, tests complete fine but get odd crashing problemHi all, I've got an issue 4A which has had all of its lower RAM replaced, TR4, TR5 as well as its CPU. It originally had quite high voltages (20-3…
... all the joints on the lower RAM, CPU and caps (I recappped ... whether it was after the RAM and TR4/TR5 was replaced ... or not. My own RAM is clearly a bit lacking ... an error. I ran the RAM test again after Manic Miner ... -
48k Speccy died, resistors getting too hot to touchHi folks, With 2 days to go till an exhibition my trusty dual-boot 48K issue 3b that I made last year has given up the ghost and I'm not sure I ha…
Check voltages on the lower RAM - I'd wager that -5v and +12v are missing, caused by a shot TR4/TR5.
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48k Speccy died, resistors getting too hot to touchHi folks, With 2 days to go till an exhibition my trusty dual-boot 48K issue 3b that I made last year has given up the ghost and I'm not sure I ha…
... took out voltage to the lower RAM which made me think my ... -
48K Issue 6a wobbly and flickering TV outputHi folks, Found an untested issue 6A Spec whilst tidying up and it had a warranty sticker on it from a past repair which seemed to be a socketed L…
... 've fixed today (keyboard membranes, lower RAM, one coil) this is the ... -
Need some help repairing an issue 3 spectrumI am looking for some help repairing an issue 3 speccy, here's what I tried so far. The speccy is not booting up correctly, when using the diagnos…
Yep, as Mark says, check the voltages first. If they're not as expected, don't run the machine longer than is absolutely necessary as the lower RAM may become further damaged.
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Need some help repairing an issue 3 spectrumI am looking for some help repairing an issue 3 speccy, here's what I tried so far. The speccy is not booting up correctly, when using the diagnos…
... cartridge is connected, just the lower ram always tests faulty. -
Need some help repairing an issue 3 spectrumI am looking for some help repairing an issue 3 speccy, here's what I tried so far. The speccy is not booting up correctly, when using the diagnos…
Actually with the lower ram removed the picture should be different, without the pauses.
https://www.youtube.com/watch?v=_v4NZGE_4hU
It's like this on my other spectrum. -
Need some help repairing an issue 3 spectrumI am looking for some help repairing an issue 3 speccy, here's what I tried so far. The speccy is not booting up correctly, when using the diagnos…
... ="patzik;873311"]Actually with the lower ram removed the picture should be ... you'd expect if all RAM was removed would indicate to ... -
Need some help repairing an issue 3 spectrumI am looking for some help repairing an issue 3 speccy, here's what I tried so far. The speccy is not booting up correctly, when using the diagnos…
... spectrum I tried without the lower ram. This video is exactly the ... you said.
With the lower ram installed all ic's test ... adressing, I'll reinstall the lower ram and do some more testing. -
Need some help repairing an issue 3 spectrumI am looking for some help repairing an issue 3 speccy, here's what I tried so far. The speccy is not booting up correctly, when using the diagnos…
... spectrum I tried without the lower ram. This video is exactly the ... you said.
With the lower ram installed all ic's test ... adressing, I'll reinstall the lower ram and do some more testing ... -
Magenta border and black screenGot my hands on a issue 3 48k machine. Did the initial resistance checks and everything seemed in order buy when I switch the machine on all I get is…
Also make sure you're getting the right voltages in the lower RAM.
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what are the differences between the 48K spectrum and the spectrum+ ?^^^^^ see above ^^^^^
... 't bloody remember!
Probably lower RAM and the power supply switching ... -
Spectrum 48+ 4S - Upper RAM issue, and now a self-created problem!I recently picked up a known-flaky spectrum off eBay, to have a bit of fun fixing it and reliving youth. It was labelled as 'keyboard duff, shows…
... . You could try changing the RAM type selection links. Suggest the ... final thought, the 16k of lower RAM is only refreshed by the ...
