-
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_…
... in response to the test voltage at the probes.
7805 voltage regulator.
Then connect the positive ... -
'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…
All voltage testing should be done with ... +5V is produced by the 7805 voltage regulator, which should work regardless of ... ) or well outside the required voltage range. The +12V supply will ... the PSU used, the mains voltage and the actual wiring on ... -
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. …
... />
With regard to the voltage readings that you have taken ... heatsink/metal tab of the 7805 voltage regulator for your meters negative (black ... -
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. …
... />
With regard to the voltage readings that you have taken ... heatsink/metal tab of the 7805 voltage regulator for your meters negative (black ... pad for negative (just replaced 7805 with a Recom unit) ... />
If I measure the voltage across the ICs I get ... -
DiscipleI have got a Disciple Disk Interface, with no manual, software. I have downloaded the PDF Manual from WOS, which says I have to load the operating…
... is overheating, looking inside, the 7805 voltage regulator is getting very hot, which ... -
DiscipleI have got a Disciple Disk Interface, with no manual, software. I have downloaded the PDF Manual from WOS, which says I have to load the operating…
... is overheating, looking inside, the 7805 voltage regulator is getting very hot, which ... fitting a better power
regulator. I will fit a Traco ... replacement
for the 7805 power regulator. Advantage is that there is ... -
Modern PSU: picture improvement?I've recently seen advertised some 'replacement power supplies' for Spectrums for which the claim is made that they may make an improvement in pictur…
... ) Cooler - as the 7805 voltage regulator effectively dissipates the extra voltage as heat, it ... -
Testing 4116 type DRAMsHappy New year All! I'm managed to find some time to repair some more Spectrums :) woo hoo. I have a couple with busted lower RAM, Sooo, I appr…
... />
I have removed the 7805 voltage regulator and powered up a 48k ... -
spectrum 48k issue 3b coloured blocksI have pucked up a nice looking plus but when powered on get black or yellow border and random coloured blocks on screen, I have taken keyboard off a…
... heat-sink attached to the 7805 voltage regulator or the case of the ... still powered up. Or the 7805 has failed bad. In any ... -
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…
... would appear that either the 7805 voltage regulator is shutting down, or there ... .
The 7805 will reduce the output voltage if any of ... , damaged track, or even the 7805 regulator being faulty could also cause ... -
Black screen on 48k+Hello peeps Just bought a 48k+ was working fine then after leaving it off over night I turned back on to get a total black screen, no border etc. …
... metal heatsink attached to the 7805 voltage regulator or to the case of ... unregulated type. This means the voltage depends on the load current ... -
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…
... disconnected.[/quote]
The voltage on pin 11 should not ... the output pin of the 7805 voltage regulator. It is the +5V ... connector.
If the voltage is fluctuating on the +5V ... the heat sink of the 7805 voltage regulator.
[b][i] ... -
Heat-sinking the spectrum 48+ :| [URL=http://s1063.photobucket.com/user/JRT480/media/Fotografia1988_zps5egnygdp.jpg.html][IMG]http://i1063.photobucket.com/albums/t515/JRT480/…
... /> As Moggy says, replace the 7805 voltage regulator with a Recom or similar ... modern switch mode regulator. That will reduce the heat ... -
Spectrum 48k Power Supply?Guys - I've got a Spectrum 48k inbound from the UK. I want to scrounge a power supply to use when it arrives. What size jack did it use and what ar…
... versions malfunction if the input voltage goes above 11.7V DC ... [/u][/b] PSU, the input voltage can be as low as ... higher the input voltage, the more heat the 7805 voltage regulator chip has to ... work with a higher input voltage.
An unexpanded 48k ... -
Spectrum 48k Power Supply?Guys - I've got a Spectrum 48k inbound from the UK. I want to scrounge a power supply to use when it arrives. What size jack did it use and what ar…
... malfunction if the input voltage goes above 11.7V ... higher the input voltage, the more heat the 7805 voltage regulator chip has ... work with a higher input voltage.
An unexpanded ... thought to keep that linear regulator running cooler. I'll ... -
Running a Spectrum from a battery...?Here's a bizarre idea that crossed my mind the other day: is it possible to run a Spectrum from a 12V battery? You see, I've got this strange idea…
If you replace the 7805 voltage regulator with a good switching type ( ... on a good quality switching regulator that is rated at 1 ... rail. So a 5V switching regulator circuit would be needed to ... times may have large voltage spikes, or voltage dips as high current ... -
Not bored with the Boards.Going through some old tapes stored rather badly I came across an unlikely item that that I must have stored away quickly with other low grade items …
... , replace with a 22uF). The voltage rating should either be the ... if you are retaining the 7805 voltage regulator.
It is possible ... -
Disabling the ROM without removing the whole thingHi! I've got my hands on a non-working issue 6a. I suspect the ROM may be bad, but other things may be faulty as well. I've read that in an otherwis…
... seconds By the way, the 7805 voltage regulator was changed to a MuRata ... switching 5V regulator, once again from retroleum, so ... -
Not bored with the Boards.Going through some old tapes stored rather badly I came across an unlikely item that that I must have stored away quickly with other low grade items …
... compare.
Changing the 7805 voltage regulator for a modern switching type ... . Cut the pins off the 7805. Remove the three cut-off ... holes. Fit the new switching regulator.
If you are ... -
Not bored with the Boards.Going through some old tapes stored rather badly I came across an unlikely item that that I must have stored away quickly with other low grade items …
... the heat sink and the 7805 voltage regulator.
The heatsink tab ... of the 7805 is 0V and the large ... track under the 7805 is 0V. As the heatsink ... help heat transfer between the 7805 tab and the heatsink. Just ... -
Not bored with the Boards.Going through some old tapes stored rather badly I came across an unlikely item that that I must have stored away quickly with other low grade items …
... uk/search?q=1A+7805+regulator+pinout&client=firefox ... %25252Fpower-supply-design-5v-7805-voltage-regulator%25252F&source=iu ... uk/search?q=1A+7805+regulator+pinout&client=firefox ... %25252Fpower-supply-design-5v-7805-voltage-regulator%25252F&source=iu ... -
Not bored with the Boards.Going through some old tapes stored rather badly I came across an unlikely item that that I must have stored away quickly with other low grade items …
... Power) in place of the 7805 voltage regulator (so no need for a ... -
ZX Spectrum Test PCB I recently read about one of these (I think it may have been the Retroleum site but I am not sure) and I thought "What a great idea" . As pictured …
... Power) in place of the 7805 voltage regulator (so no need for a ... -
ZX Spectrum Test PCB I recently read about one of these (I think it may have been the Retroleum site but I am not sure) and I thought "What a great idea" . As pictured …
... by testing all the DC voltage rails. And if all the ... /> But I think changing the 7805 voltage regulator would be my next move ... -
ZX Spectrum 48K it only shows colored barsHello, I'm new to the forum and I need help with a ZX Spectrum 48K which I bought recently unfortunately defective. I want to mention that before t…
... example, the heatsink of the 7805 voltage regulator), using a test probe, test ... -
Troubleshooting my +2To put this in context: a while back (i.e. late last year and earlier this year) I was looking to put together a compilation of modern Spectrum games…
... .5V on load. The unloaded voltage can be higher...
voltage of 10.5V or more ... in the heatsink for the 7805 voltage regulator getting rather hotter than normal ... -
Troubleshooting my +2To put this in context: a while back (i.e. late last year and earlier this year) I was looking to put together a compilation of modern Spectrum games…
... 's as long as the voltage and current are sufficient and ... .5V on load. The unloaded voltage can be higher...
Note ... that outputs a loaded output voltage of 10.5V or more ... in the heatsink for the 7805 voltage regulator getting rather hotter than normal ... -
Broken Issue 2 - likely culpritsI've just got hold of an issue 2 spectrum with an interesting layout (heatsink is vertical and goes down to the speaker, some variable resistors and …
... holding the heatsink and the 7805 voltage regulator nice and tight?
[*]Test ... -
ZX Spectrum+ new membrane not working properlyHi! I recently got myself a ZX Spectrum+ . It had the classic broken membrane problem (most keys didn't work and those that did were wrong). So I or…
... metal heatsink for the 5V 7805 voltage regulator were known about back in ... -
help with issue 3 48k speccy after recap and new tr4 and tr5I have a 48K speccy that was not working. After recapping and replacing TR4 and TR5 it came back to life However after a short while running weird …
... /or TR5 die, as the 7805 voltage regulator suppliers the +5V. However if ... the +5V from the 7805 as a reference voltage. A failure of ...
