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Burned finger temp on rubber 48k heatsink normal?Ok so i opened it up because a few keys started to act up and i noticed that after burning my hand the heatsink was that hot i could actually smell t…
... switch mode regulator -220mA (400mA)
- with Lower RAM module -105mA (295mA ... )
- with Upper RAM module -35mA (260mA)
- with ... -
Help put this back to 16kSo this issue 2 arrived today and ive opened it up just to nosey and confirm that infact it is an issue 2. Now from the help offered in an earlier po…
... . I believe it can measure voltage and current without a battery ... chances of damaging the lower RAM. However, if you've ... supply voltages at the lower RAM.
- If the voltages ... your description of overheating lower RAM ICs, I'd probably remove ... -
ZX Spectrum 48K AV IssueOK so I dugout my old 48K Speccy today and decided to AV mod it. I did the mod (pretty easy) but the picture I am getting is this. [url=http://posti…
... replacements is whether the various voltage rail measurements have changed.
voltage rails. As you've removed the RAM this is ... -
ZX Spectrum 48K AV IssueOK so I dugout my old 48K Speccy today and decided to AV mod it. I did the mod (pretty easy) but the picture I am getting is this. [url=http://posti…
... replacements is whether the various voltage rail measurements have changed.
voltage rails. As you've removed the RAM this is ... -
The ULA6C001E-5...Hi everybody, I have been continuing my Quest for the Holy ULA, and have today taken delivery of a ULA6C001E-5. Now, the -6 was used in Issue 3 boar…
... a new position for the regulator and shape of heatsink.
regulator and the heatsink shape. Issue ... the modulator for the 32K RAM board. In Issue Two the ... 32K RAM was moved onto the main ... -
Youtube vids of US guy converting speccy into handheldDidn't see it posted here but thought it was a pretty interesting project. Part 1 and 2 here, more to follow. [youtube]6GcwcyL9LgM[/youtube] [you…
ZX81 + 16k RAM Pack + Original PSU... What's it worth?Hey guys Got my ZX81 this morning its in excellent condition.. [IMG]http://s30.postimg.org/iwetzxku9/IMG_20140818_142443.jpg[/IMG] However, my T…
... an update - I measured the voltage using the old PSU and ... minutes when measured at the regulator.
So I made ...RAM issue for potential 48k buy?Hi guys I've got a 48k in my sight for ?20 but... it has an issue: [QUOTE]"I tested the computer and only displayed a distorted screen. Coloured …
The 'lower' 16k of RAM (made up of eight 4116 ... cause. Or the on board voltage inverter circuit, which can fail ...Next step for fixing my speccy?Hi guys, I've picked up my faulty Spectrum aiming to fix it. So I followed the excellent JouledperCoulomb videos on Youtube for the basics and I am …
... you have something like the voltage levels you should have, ie ... to run the lower RAM - this means the voltage converter circuit based ... to remove all the lower RAM chips anyway, so personally I ... . Assuming voltage levels are ok now, fit Zorn's lower RAM board ...Next step for fixing my speccy?Hi guys, I've picked up my faulty Spectrum aiming to fix it. So I followed the excellent JouledperCoulomb videos on Youtube for the basics and I am …
... you have something like the voltage levels you should have, ie ... to run the lower RAM - this means the voltage converter circuit based ... Assuming voltage levels are ok now, fit Zorn's lower RAM board ... /> I'll remove the lower ram, check the voltages, fit sockets ...ZX81 Unwell... TV or The ZX81??Hi all I finally got a RF cable today so i could test my ZX81 at last... sadly it's not great news although I'm hopeful that it's the TV...? All I'…
... . Diodes were overheating. The voltage at the regulator started at 10.4v ...Short Circuit Damage?Hey Spectrum fans, Currently trying to diagnose what is wrong with my 48K Issue 4B ZX Spectrum. The initial problem was the fact it would not boot -…
... that it was a lower RAM 4116 IC that you reversed ... you may have killed the voltage conversion circuitry that provides the ... /> With a multimeter on DC voltage range,candy the ground at ...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_…
... on my meter.
Regulator:
[IMG]http://s26 ... />
Top right of the RAM:
[IMG]http://s26 ... />
Bottom right of the RAM:
[IMG]http://s26 ... />
Bottom left of the RAM:
[IMG]http://s26 ...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_…
... at one of the lower RAM IC's with the ground ... or more of the lower RAM IC's have gone bad ... , although upper RAM faults could also cause this ... .
Link for both voltage check and colour adjustment is ...ZX81 ULA questionRecently, I got a nice bundle of kit comprising of a ZX81, Memotech keyboard, PSU and brand new 16K Sinclair Memory pack. The ZX81 has a ULA with no…
... switched regulator and ZX8 Module with one having an internal RAM upgrades ... I read that the external RAM can cause problems.
'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…
... voltage?
I think 5v probably goes to where the regulator ... the ground hole in the regulator location be sufficient to replace ...48k - Why Won't it Buzzzz?Hi WOS ;) I bought a load of Spectrum games off eBay and thrown in for good measure was a 48k 1984 Issue 6a circuit board that I was told was for sp…
So could a faulty lower RAM IC be holding the voltage low across the 12v rail. If not how do I test for a short between the RAM IC's and the 12v rail?Faulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
... coil (sick Spectrums with bad voltage are often silent as they ... need to isolate the faulty RAM chip.. usually by taking them ...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_…
... /> [LIST=1]
[*]7805 regulator to get voltage to anywhere
[*]TR4 ...Hot plugable edge connector?Could the spectrum's edge connector have been made hot plugable without adding much to the manifacturing costs? I was thinking along the lines of a…
... kills the voltage converter circuit (and so destroys the lower RAM) or ... it; for example, an upper RAM IC when power is applied ...Noob repairs of an S2 and S6AI received two Spectrums a Series 2 and a Series 6A both of which are not working. I don't know anything about electronics so thought my lad and I wo…
... part of the voltage generation circuitry and the lower RAM can be ...ZX Spectrum upper RAM module (4532/4164 replacement)Following the [URL="http://zx.zigg.net/LRR/"]lower RAM replacement module[/URL], there have been quite a lot of requests for something similar for th…
... means:
- Lower/Upper RAM module replacements
- switch mode ... switch mode regulator -220mA (400mA)
- with Lower RAM module -105mA (295mA ... )
- with Upper RAM module -35mA (260mA)
- with ...ZX81 internal RAM board?Just a quick question to Zorn (amongst others). What would the issues be with fitting one of Zorn's RAM boards into an unexpanded ZX81? Seems to me…
... new membrane and a switching regulator.
I was wondering ... any external device that includes RAM and which plugs into the ... (including a Sinclair or Memotech RAM pack and a ZXPand) will ... disable the internal RAM when plugged in.
< ...Modern PSUHello everyone, I'm looking for a modern PSU for my Spectrums and my dual set of 3.5'' floppy drive+HxC floppy emulator. The one for Spectrum should …
... with a regulator to about 9V. This will lower the voltage drop ... on the internal regulator and thus dissipate ... heat caused by the voltage drop over the regulator.
... 12V supply with a 9v regulator which feeds the Spectrum ...Modern PSUHello everyone, I'm looking for a modern PSU for my Spectrums and my dual set of 3.5'' floppy drive+HxC floppy emulator. The one for Spectrum should …
... very forgiving with the input voltage as discussed in many posts ... forgiving about too high a voltage. I've made a mess ... is fine up a silly voltage, (Although it would still fail ... a ram chip or two.
Keep your unregulated voltage between ...Modern PSUHello everyone, I'm looking for a modern PSU for my Spectrums and my dual set of 3.5'' floppy drive+HxC floppy emulator. The one for Spectrum should …
... forgiving about too high a voltage. I've made a mess ... ).
Keep your unregulated voltage between 8 and 12v...[/QUOTE ... -load measurements taken at the regulator.
Personally I used ...Modern PSUHello everyone, I'm looking for a modern PSU for my Spectrums and my dual set of 3.5'' floppy drive+HxC floppy emulator. The one for Spectrum should …
... forgiving about too high a voltage. I've made a ... is fine up a silly voltage, (Although it would still ... a ram chip or two.
Keep your unregulated voltage ... running at a higher input voltage, and so is not ... a on-load output voltage of 12V or more.< ...Weird symptom number 2...I got a new keyboard membrane for my Spectrum+ plugged it in and low and behold the weird left to right printing of the copyright message disappeared…
... metal they bolt the regulator chip onto is smaller ... try. Measure the output voltage of your power supply - ... , you are pushing the regulator hard, and much above ... There will be a voltage drop of about 0. ... you can reduce the voltage output if necessary, just ...ZX81 and Analogue TVsI recently bought a really nice ZX81 on ebay in amazing condition, but I'm having issues tuning in an old analogue TV to lock onto the signal. I und…
... video/color/UDG/HRG/joystick/RAM expansion - did not check the ... would prevent my walking high voltage generator (the cat) zapping the ...Please explain Spectrum FPGA-clones to meI've been using the great ZXDS-emulator on the DS XL so far, which is great. But I kinda missed toying around with hardware. I've tried bidding on a …
... as there'd be noticeable voltage differences on the edge connector ... connected to two devices: upper RAM and ROM. The address bus ...
