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Voltage regulator replacement?I have an 48K issue 3B that has (for unknown reasons) had one of the legs on the voltage regulator broken off. It looks like a simple replacement job…
... of the legs on the voltage regulator broken off. It looks like ... could do.
The regulator is marked:-
[code]T ... -
Missing Voltage RegulatorHello all and a very merry 2-days-after-the-speccys-25th-birthday to you all! Okay, I've just received my brand spanking new 48K keyboard membranes …
... odd reason ripped off the Voltage Regulator and heatsink. Is there anything ... -
Plus D Voltage Regulator OrientationHi, I?ve got a Plus D Disc Interface circuit board without case from a friend. Sadly he sends it to me without care for proper packaging. So it arr…
... to me with the voltage regulator hanging around,
... the three pins from the voltage regulator tear off.
voltage regulator was soldered.
The voltage regulator has printed "F M0247 MC7805C ... -
Power supply voltage regulator circuitRelating to [url="https://www.worldofspectrum.org/forums/discussion/56142/"]this topic[/url] I have managed to acquire this little accessory, which I…
... />
It acts as a voltage regulator undoubtedly but I am wondering ... -
how to set voltage regulator to the correct setting ?On the power supply that is broken it says AC adapter INPUT : 230v 50Hz OUTPUT ; 9v 200mA Regulated On the variable voltage adapter i have the…
... />
On the variable voltage adapter i have there is ... do to set the correct voltage ? -
PC power source and Spectrums.I'm planning to use a basic PC ATX power source (300W) for all my sinclair equipment, but I have two questions: - I've read about some nasty things …
... . I remember something about a RAM chip failure destroying internal power ... the 7805 or use another voltage regulator to get +9v? A 7809 ... be enough, so what other regulator?
- And (not related ... -
Question about 7805 regulatorOne of my common practices when I service a ZX machine, is to replace the electrolytic caps as well as the 7805 regulator and some times the ztx650 t…
... machines used the same 7805 voltage regulator but totally by accident I ... uses an 78S05 regulator which is a 2A regulator. That got me ... showing a regular GL7805 (1A) regulator, and the ones on my ... service guide...
"78S05 2A regulator can be used, but hardly ... -
2 48K speccys dead..Hey guys! I've got two of our rubbery friends with me that need some help. They've been like this for some time, but I would like to try and fix th…
... that, so I suspect a RAM problem... Now, when I plug ... though it might be the voltage regulator at first but all the ... -
Repairing a faulty 48K issue 2.I am investigating one of a pair of non-working issue 2 48K Spectrums that have been sitting in a cupboard untouched for quite a few years. I haven…
... />
I found its voltage regulator not to be working so ... regulator I can now measure +5V at all the RAM ... br />
The lower RAM chips are marked ITT 4116 ... RAS signals at all RAM chips (upper and lower ... and input pins of all RAM chips
(upper ... -
Semi-Dead Spectrum - Help RequestedI have finally got my hands on my two old Spectrums - neither of which work, but ideally I hope to get both of them working again. Spectrum number o…
... />
I have replaced the Voltage Regulator and the Spectrum now "boots ... I be looking at a RAM fault?
Ideas anyone ... -
Issue 2 video problemHello all, Need some help with an issue 2 board that I 'm trying to restore. I've replaced all the electrolytic capacitors, changed the voltage regu…
... voltage regulator, tr4, and a Zener and the board came to life. Ram ... -
PlusD Mini: implementing the CPLDI am doing my first attempts on creating a CPLD to use as replacement for the PlusD's GAL (and other logic lateron). I use the Xilinx XC9500XL series…
... I added the 3.3V voltage regulator, wired the chip to a ...
| f17);
// ROM/RAM select (PlusD paged in when ...
+ f17
;ROM/RAM select (PlusD paged in when ... -
Flashing coloured blocks - diagnosisHiya, hope this is the right place for this... Was given an Issue 2 48K by a someone yesterday that hasn't been powered on in 20 years, which works …
... down to the voltage regulator, TR4 transistor, ULA, or RAM. I've measured ... into the Speccy), and the voltage regulator which gets 10.88V and ... /> I've tried touching the RAM chips to see if heat ... -
ZX Spectrum Pre-regulator DesignCarrying on from the "[URL="http://www.worldofspectrum.org/forums/showthread.php?t=44486"]Issue 2 crashes after about 30 mins[/URL]" thread... [QUOT…
... dissipated by the 7805 internal voltage regulator and heat sink.
< ... br /> Instead, the pre-regulator circuit helps out with the ... br /> Output voltage from the [U][B]Pre-regulator[/B][/U] ... br /> Output voltage from the [U][B]Pre-regulator[/B][/U] ... -
Help with 128k greyHello friends, need some help here on try fixing a +2 grey spectrum128. To keep it short, opened the case and the voltage regulator was missing, the …
... , opened the case and the voltage regulator was missing, the cables where ... point I desoldered all the ram chips and after testing 4 ... them where faulty. Replaced the ram chips and powered up with ... ramtest eprom fitted and... "lower" ram test passed. Then an error ... -
I broke my 48k Speccy!!!!Hey guys, I am looking for some advice, I hope you can point me in the right direction. So, I went about replacing all the capacitors on my issue 4…
... /> The voltages on the lower ram are well out of whack ...
I checked the voltage regulator, TR4 and TR5 and as ... left hand leg on the voltage regulator using the 200k meter setting ... have issues with my lower ram now due to the weird ... -
Power issues on a 6A 48 K SpectrumHello all! I decided to take another look at my 6A Spectrum that I broke via a bad joystick adapter, I’ve removed the bottom 16K ram and replaced…
... ’ve removed the bottom 16K ram and replaced TR4 and TR5 ... left hand leg of the voltage regulator gives a reading of 29 ... wrong here.
[b]RAM test:[/b]
previously I ... -
48k Issue 6a Very sick indeed.Hi Guys. I have a 48k Issue 6a board that shows a white screen with grey border. The white screen has three black squares spaced equally on the le…
... a new 7805 regulator, socketed lower and upper RAM, switched ram from another ... coil.
My lower RAM voltages are -5V = -029.5mV ... are way off. If the voltage regulator, capacitors, and TR4 and TR5 ... -
Replacing voltage regulators - need to sanity check a few things pleaseHi Everyone I'm in the process (with a lot of help from some friends at Greenford Computer Club), of giving my three Speccys some much needed prev…
... kits)
[b]Voltage regulators:[/b]
I known ... is a 78S05 5v 2a voltage regulator in the +2, ... 5v 2a switch mode regulator in order to reduce ... to replace its legacy regulator, or whether to use ... 5v 1a switch mode regulator. Similarly, I also ... -
Investronica Inves Spectrum +Hi, Has anyone here ever heard of the Investronica Inves Spectrum +? This site [url="http://www.silicium.org/uk/sinclair/inves.htm"]http://www.sili…
... Sinclair range of Spectrums. The RAM was composed by just two ... mapped in that area). The RAM refresh is made by four ... specifically for that purpose. The voltage regulator is placed elsewhere and has ... composite. It also lacks the voltage connections -5, +12 and ... -
Best replacement for ZTX650?What is the best replacement transistor for the obsolete ZTX650? I've read that TIP31 will do the trick. Is there a decent equivalent from the BC or …
... .
In addition to the RAM, also check:
TR5 (check ... .
I hope its the RAM because if its not it ... is rather unusual for bad RAM to cause such a symptom ... has the same transistors and voltage regulator (7805) as a 48k (it ... -
Zx Spectrum Laptop (again)I've been reading all the old treads about a possible portable speccy. I even found the one about the Speccy Laptop. But it seems there's a lot of ne…
... CMOS Flash device, and replace RAM with a single CMOS static ... on flash rather than static RAM and so retains its configuration ... SOIC surface mount packages for RAM and ROM. These are still ... 't even get the heatsinkless voltage regulator hot) and very, very cool ... -
Zx Spectrum Laptop (again)I've been reading all the old treads about a possible portable speccy. I even found the one about the Speccy Laptop. But it seems there's a lot of ne…
... 16K pages), single 512K static RAM (I think this can be ... very low power - note the voltage regulator in the upper left doesn ... fraction of the power. The voltage regulator without a heatsink runs cooler ... -
Dead Spectrum +Hi all, I've recently dug out my old Spectrum + with the idea of repairing it. When I last looked at it, when I was much younger, I was soldering a …
... getting 5v off the 7805 voltage regulator.
You can ... appropriate pins of the 4116 RAM (awful devices that require 4 ... s also worth checking that RAM chips aren't getting hot ... warm) which would indicate failed RAM rather than failed power circuits ... -
toasted soeccysHello, ive jsut bought a pair of speccys on ebay (one 16k issue 2 & a prob 48k issue 3) unfortunaly the genius who sold them tried to see if the wor…
... getting 5v off the 7805 voltage regulator.
You can ... appropriate pins of the 4116 RAM (awful devices that require 4 ... s also worth checking that RAM chips aren't getting hot ... warm) which would indicate failed RAM rather than failed power circuits ... -
toasted soeccysHello, ive jsut bought a pair of speccys on ebay (one 16k issue 2 & a prob 48k issue 3) unfortunaly the genius who sold them tried to see if the wor…
... here - such as the input voltage will always be -
Dead +2B, help required...It was bought defective on ebay. It came with two faults: a "dead" power supply (it was the fuse) and a faulty main unit. The power supply is now re…
... (well, apart from the 7805 voltage regulator) that gets measurably above ambient ... I have, none of the RAM chips warm up at all ... -
On a 48K issue 6A......how can i isolate the 32K block? I want to test if there is any fault on the 4116's , leaving the 4532's out of the equation. Will removing the …
... voltages are right on lower RAM, the 4116s are not single ... is supplied by the 7805 voltage regulator, the rest by a small ... -
On a 48K issue 6A......how can i isolate the 32K block? I want to test if there is any fault on the 4116's , leaving the 4532's out of the equation. Will removing the …
... voltages to run the lower RAM?
Test TR3, that ... 'll make the lower RAM appear dodgy if it's ... .[/QUOTE]
The lower ram voltages are fine and i ... is supplied by the 7805 voltage regulator, the rest by a small ... -
spectrum PSU'sI've read contradictory info on which psu(ie amp rating) is for which spectrum. :confused: The models and amp ratings are 1.2A, 1.4, 1.85 and 48k, …
... (not +2a/3) is a voltage regulator, the 7805. It's a ... inside the Spectrum is another regulator, only this one is ... - it converts the incoming voltage to three separate voltages, which ... RAM block etc.
So, since the incoming unstablised voltage ...
