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Using an ATX power supply - Spectrum 48kOK... I have an Issue 3 48K model and the DC-DC converter does not work and I can?t make it work. :( There is a MOD to use an ATX power supply on the…
[QUOTE=Turrican;635259]OK... I have an Issue 3 48K model and the DC-DC converter does not work and I can?t make it work. :(
[/QUOTE]
What part of the DC-DC circuit does not work? Which voltages do you have and which are not there? -
Need some advice about electronicsI have wired up an ATX power supply to power my spectrums through a DC-DC converter that gives 9V from the +12V rail. It works well. However, I also …
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The DC-DC converter and choke for the ZX ... -
Issue 3 power problemHi all, I have an issue 3 board with an odd power problem, I have no -5V in fact, measuring the voltage on this line leads to a surprising result : …
Well replaced TR4/TR5 again, and still no -5V :(
Cheers.
Phill. -
ZX Spectrum power supplyHi, I'm looking for a small lightweight power supply that would be a perfect substitute for the original, it's meant for a video patched zx spectrum…
... PC power supply with a DC to DC converter to get 9V out ... -
12V -> 9VI found this simple dc-dc converter: [url]http://www.mcrent.com/workbench/dcdc1216/[/url] it converts 12V to 16V, can it be used to produce 9V by mod…
... ;655406]I found this simple dc-dc converter:
[url]http://www.mcrent ... ". The topology of a boost converter (which is what this IC ... ) is different from a buck converter (which is what you want ... you want to make a DC-DC converter that steps down). -
Correction of +2 hardware errorsThis is a collection of various pieces of information picked up from various places, including a lot from this forum. I have edited it and reworded i…
If all three TR4, TR5 and TR7 transistors were wrongly installed in reverse by amstrad (except just tr4), why didn't anyone else mention it?
Even at Velesoft's web page, there's only info about fixing the tr4.... -
+2 grey rf out problemI got a kind of broken +2. it basically works, but with a annoying rf out problem. When screen goes black (eg. after border 0: paper 0 command) it l…
Can anyone else confirm that all three transistors (TR4, TR5 and TR7 (all type 2N3904)) need to be reversed before I start doing it? :) -
Correction of +2 hardware errorsThis is a collection of various pieces of information picked up from various places, including a lot from this forum. I have edited it and reworded i…
... =gtsamour;674982]If all three TR4, TR5 and TR7 transistors were wrongly ... reverse by amstrad (except just tr4), why didn't anyone else ... only info about fixing the tr4....[/QUOTE]
I think ... -
+2 (Grey) and AT/ATX PSUAny ideas on the best way to power a grey +2 board from an AT or ATX PSU? Looking at the schematic, I could do this one of two ways... 1: Bypass th…
... I could get a 2A DC-DC Converter without getting ripped off or ... -
48k fuzzy screen errorHi all, I just got a ZX Spectrum 48k (rubber keys) from eBay and when I plug it in the main screen on the TV is all fuzzy and garbled in the middle.…
... where the fault lies. The DC-DC converter circuit is probably broken too ... -
48k + Spectrum Issue 4S Display IssueHi all! Brand new user here. Growing up I had a zx spectrum for a little bit, and recently I have bought a working 48k + Spectrum (Issue 4). I was…
... value. I have also replaced TR4, TR5 and removed all the 4116 ... -
48k + Spectrum Issue 4S Display IssueHi all! Brand new user here. Growing up I had a zx spectrum for a little bit, and recently I have bought a working 48k + Spectrum (Issue 4). I was…
... odd has happened to the DC-DC converter circuit. Perhaps some shorted windings ... -
48k + Spectrum Issue 4S Display IssueHi all! Brand new user here. Growing up I had a zx spectrum for a little bit, and recently I have bought a working 48k + Spectrum (Issue 4). I was…
... the later design of Spectrum DC-DC converter. Try with your bench power ... -
CapacitorsSorry, another question... I've done a bit of looking around, although after a couple of beers this may not have been as systematic as usual, but I …
... production of 12V in the DC-DC converter, where present and having different ... capacitance here can stop the DC-DC converter circuit from working. All that ... -
Spectrum+ Noisey Picture ProblemHi fellow Spec-chums I need your help! I've recently brought a 48K+ Spectrum(issue 6A) that I'm trying to repair. I did all initial tests on it prio…
Good to get some feedback after a successful repair. I learned something new today, after my recent video signal experience with TR4/TR5. Thanks! -
Which ULA?Just a quick question, more of interest rather than immediate need... I am thinking ahead about the repair of an Issue 2 board, and also an Issue 6A …
... out the voltage regulator, TR4 and Coil on the issue 2, which ... -
ZX Spectrum 48k Issue 2 Faulty Ram?Hi, I have a faulty ZX Spectrum Issue 2 motherboard. Looks in very tidy condition. Though I'm getting random columns of blocks and flashing cursors…
... make sure the Spectrum's DC-DC converter circuit is working properly. This ... 'll still want the voltage converter to be working as the ... -
Cascading transistorsMiguel (mcleod_ideafix) alerted me on an aspect of a design I'm working on where I am cascading transistors, which may give problems. This is the par…
... .
3. Meanwhile, the DC-DC internal converter, begins to generate 12V and ... to feed lower RAM. The DC-DC converter uses the +5V supply, so ... -
Issue 3 weird modification(Doing my best to be a one-man question asking machine tonight - forgive me!) I noticed the following mod that I don't recall seeing anywhere else o…
It isn't very strange. There are many like that. I think many were factory assembled in that manner.
It was done to implement the later (issue 3B) variation of the DC-DC converter circuit. -
Issue 4A repair attemptI think I need some help. I have a nice Issue 4A main board here, which does not give out any video signal. I checked some voltages (the ones that se…
... the 12V output of the DC-DC converter circuit. Is 12V present at ... -
Correction of +2 hardware errorsThis is a collection of various pieces of information picked up from various places, including a lot from this forum. I have edited it and reworded i…
... =gtsamour;674982]If all three TR4, TR5 and TR7 transistors were wrongly ... reverse by amstrad (except just tr4), why didn't anyone else ... only info about fixing the tr4....[/QUOTE]
I've ... -
Spectrum +2 Cable Nightmare -TTL-Composite-RGB ???Just got myself a Spectrum+2 Grey model with rgb scart cable The system works great on my livingroom lcd with the supplied cable, so good news here …
... get your soldering iron out. TR4, TR5 and TR7 are all the ... way around. If you turn TR4 (next to the modulator, right ... -
Another broken SpeccyHi all I have been given another ZX Spectrum, this time it has a really odd problem as you can see in the video: [URL="http://youtu.be/ZOSiBEYQD7w"…
... likely one or both of TR4/TR5 have died and perhaps one ... -
Issue 4A black paper, white borderJust had one of these through, nice yellow pcb! Everything but the ULA soldered in. On power up I get black paper, white border and some intermitten…
I'd replace all of the electrolytics first, then see where the voltages are before looking at TR4/TR5.
B -
Didaktik Gama and M manualsI?m looking for manuals for the Czech Spectrum clones Didaktik Gama and M. Thought this would be an easy task, but I couldn?t find any user or servic…
... 2A PSU and use a DC-DC converter module to convert +5V to ... -
Didaktik Gama and M manualsI?m looking for manuals for the Czech Spectrum clones Didaktik Gama and M. Thought this would be an easy task, but I couldn?t find any user or servic…
Thanks Mark. A "DC-DC converter module" is something like a Traco thing, which needs to sit on a board? My fingers are all thumbs, so I would be glad if someone could offer such 5V/20V PSU to me. -
Didaktik Gama and M manualsI?m looking for manuals for the Czech Spectrum clones Didaktik Gama and M. Thought this would be an easy task, but I couldn?t find any user or servic…
Search eBay for "LM2577 DC-DC converter". I have [URL="http://www. ... ]:-
New LM2577 DC-DC to DC Adjustable Converter Step-up Circuit Board ... -
I've had better nights...So I got a broken issue 2 today, case in good nick but the diags board showing multiple failures in both lower/upper RAM. Never mind, good as a spare…
... is how a 4116-induced TR4 failure managed to kill the ... turned pin sockets for TR4/TR5 so swapping out TR4 took seconds :)
I've had better nights...So I got a broken issue 2 today, case in good nick but the diags board showing multiple failures in both lower/upper RAM. Never mind, good as a spare…
... is how a 4116-induced TR4 failure managed to kill the ... turned pin sockets for TR4/TR5 so swapping out TR4 took seconds :)
