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Replacing ZTX650 with BD139Today I blew up one of the GALs on one of my DivIDEs while testing on my Toastrack. Shorted M1 with 12V and the 12V circuit broke. I had to replace T…
Any transistor that does not get hot and that leads to the correct output voltages is ok. I used several different types as for example the SD349 (from former GDR) which works since many years without any problems.
Greets Ingo. -
Needing new capacitors. Where to buy online?Hi. I need new axial capacitors for a whole bunch of Speccy boards I have. Problem is, it's been hard to buy some of them online. Some shops will onl…
... replacements tho as the exact voltages aren't to be found ... 6v will be 25V. Ultrarated voltages but at least if it ... -
ZX 48 issue 4S no s-video possible?No s-video on ZX 48 issue 4S possible? I have had this mod on my issue 4A. But this did not work with my 4S. On C65 is no chrominance signal. Here …
I replaced the C839s which I could not find any datasheet on (TR8 and TR9) with some BC546. Hard to say if there was much of an improvement at all. -
Spectranet updateHi all It's been a busy summer, and in any case I've wanted a little bit of a break from doing Speccy stuff to avoid it getting old (pun intended). …
... board, it has 3 supply voltages, semi-custom logic about half ... -
Diagnosing a strange software fault in a 48kHi, A friend gave me a 48k, which I am very keen to restore. The spectrum 48k was my first computer over 20 years ago and I owe my ability to code t…
... work, test all the voltages.
Unstable voltages and incorrect voltage levels ... -
Diagnosing a strange software fault in a 48kHi, A friend gave me a 48k, which I am very keen to restore. The spectrum 48k was my first computer over 20 years ago and I owe my ability to code t…
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When done: [B]check voltages![/B] (+5, -5, +12V, place ... -
Diagnosing a strange software fault in a 48kHi, A friend gave me a 48k, which I am very keen to restore. The spectrum 48k was my first computer over 20 years ago and I owe my ability to code t…
... the caps and check the voltages at some point. Thanks for ... -
Over clocking cpu desktop pc.Is it easy? any good online guides? is it worth doing?
... have control over the various voltages in your BIOS?.
Is ... enough to play with the voltages. Also they go cheap on ... -
Over clocking cpu desktop pc.Is it easy? any good online guides? is it worth doing?
Buy a MoBo like a Rampage Extreme II...O/C'ing is controlled by a little onboard switch...which manages voltages etc for you. -
48k faultyHi guys! I have a 48k that, currently, presents 2 problems: 1 - Can?t sync to TV correctly. I get a lot of noise and the characters appear to be inc…
... too. When done, check supply voltages (+5, +12 and -5V) at ... that's done AND (all) voltages are within nominal range: report ... -
WIP: ULAPlus hardware implementationThis aims to be an "almost" plug-in replacement for the Sinclair ULA chip fitted in Spectrum 16K/48K/Plus machines. It comes in a form of a small PC…
... allows me to put different voltages into the AUDIO_OUT pin so ... -
What's the correct Spectrum colour palette?Prompted by the recent SCR-to-GIF conversion thread, I was pondering writing one in Z80 assembler. As I did a LZW compression routine a while ago tha…
... , there is no specific ULA voltages on the you can say ... -
Is this Spectrum dead?Hello. First post and all that... I have an old Spectrum +3 which has sat on a shelf for many years. Yesterday, when I plugged it in for the first…
The red LED is fed off the +5V line from the PSU. So if you have a meter check if you have the correct voltages on the output plug (be careful not to short any of the connections).
Or if you have another PSU, test the Speccy again.
Mark -
My 48K Speccy has died.Hi fellow WoSer's! Wondering if you could help me with my rubber key 48k Spectrum, which died on me this afternoon. It is one I prevoiusly fixed up j…
... lower RAM, make sure all voltages are present (search for TMS4116 ... -
My 48K Speccy has died.Hi fellow WoSer's! Wondering if you could help me with my rubber key 48k Spectrum, which died on me this afternoon. It is one I prevoiusly fixed up j…
... like Winston said: check supply voltages first. -
My 48K Speccy has died.Hi fellow WoSer's! Wondering if you could help me with my rubber key 48k Spectrum, which died on me this afternoon. It is one I prevoiusly fixed up j…
... replies. I will check the voltages tomorrow and see if they ... easy.
If the voltages are good then I will ... -
My 48K Speccy has died.Hi fellow WoSer's! Wondering if you could help me with my rubber key 48k Spectrum, which died on me this afternoon. It is one I prevoiusly fixed up j…
... signal and make all the voltages back to as they were ... -
Issue 2 problemHeres a video of what happens when I fire up an Issue 2 board ive had hanging around for ages, this is with Paul Farrows RAM test cart in btw If this…
The border turns 'white' (which I've read is done by the Z80), and it looks like a RAM test is being done. So if it's one of the causes you mention, I'm betting lower 16K RAM.
Btw. did you check supply voltages? -
Issue 2 problemHeres a video of what happens when I fire up an Issue 2 board ive had hanging around for ages, this is with Paul Farrows RAM test cart in btw If this…
I checked the supply voltages, all within range, now then, which lower memory to start with, sods law if I work from left to right it will be the one furthest to the right and vice vera! lol -
My 48K Speccy has died.Hi fellow WoSer's! Wondering if you could help me with my rubber key 48k Spectrum, which died on me this afternoon. It is one I prevoiusly fixed up j…
... had chance to check the voltages yet and with Ian offering ... -
Sinclair ZX Spectrum FAILS latest radio noise rules SHOCKCan I really be the first to have mention this? Article on El Reg reports: [url]http://www.theregister.co.uk/2012/12/13/sinclair_spectrum_fails_mode…
On complex boards like a PC you don't route regulated voltages around across the board either. It's easier to put a separate small voltage regulator and honking great filter caps near each subsystem and power it all off big fat 12v rails -
FS: Spectrum +2ARather than muck about with ebay again, throwing it out here, working Spectrum +2A, on its own, ?25 + shipping, PM me if anyones interested. [url=htt…
... small power supply with three voltages including -12V.
A standard ... -
FS: Spectrum +2ARather than muck about with ebay again, throwing it out here, working Spectrum +2A, on its own, ?25 + shipping, PM me if anyones interested. [url=htt…
... small power supply with three voltages including -12V.
A standard ... -
Another cause for DivIDE problems on 48K'sThe last months some topics were opened to discuss problems with 48K ZX Spectrums and DivIDE. Sofar we found: - Bad Z80's because of poor fanout (si…
... simulation and choose to see voltages at the input of both ... -
Another cause for DivIDE problems on 48K'sThe last months some topics were opened to discuss problems with 48K ZX Spectrums and DivIDE. Sofar we found: - Bad Z80's because of poor fanout (si…
... simulation and choose to see voltages at the input of both ... -
No composite from +2 greyHello all! My grey +2 is not showing any image from the composite pin, but if I use the RGB connections, it works. Until past week it was working (th…
The problem was the TR9 has burnt. :)
Velesoft told me to change the ZTX650 and now all is working. :)
Thanks for all! -
ZX Spectrum 48K help and Hello :)Hello out there I am a long time admirer of the ZX Spectrum range of computers my first go at one was in the early 1980s with my dads ZX 80 now its …
... whether the various power supply voltages are present in the correct ... -
ZX Spectrum 48K help and Hello :)Hello out there I am a long time admirer of the ZX Spectrum range of computers my first go at one was in the early 1980s with my dads ZX 80 now its …
... supply that supplies the odd voltages the 4116 memory needs is ... .
First check the voltages to the lower 16K RAM ... chips, if any of these voltages are not present (especially -5v ... detail).
If the voltages are present, the lower 16K ... -
Want a new old PC.Does anyone know of any good place that sell slightly older desktop PC's very cheap? The motherboard in mine is on its way out. Think there is a cr…
... .
I tested the voltages and the current both loaded ...
