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Whats wrong with my 128k?The little power converter (the thing with three legs) that sits on the cooling fin was broken, so I bought a new power converter and replaced it. Bu…
The Voltage Regulator you bough (7805), was it a 1A type? ... work correctly. Generally I say, 7805 with 1Amp or more is ... . Don't try it with 7805 that have plastic heat spreader ... a chance that the damaged 7805 damaged other components in Speccy ... -
Whats wrong with my 128k?The little power converter (the thing with three legs) that sits on the cooling fin was broken, so I bought a new power converter and replaced it. Bu…
... besides that it was a 7805. On it it reads = KIA ... /> I also had a spare 7805 I took from an old ... -
Whats wrong with my 128k?The little power converter (the thing with three legs) that sits on the cooling fin was broken, so I bought a new power converter and replaced it. Bu…
... okay, I guess, the poor 7805 blowed the TV-encoder chip. -
Will Spectrum run @ 60Hz?Sorry to overlap w/ my other recent post, but want to know, if I grab a Spectrum and use it in America with a voltage converter or a different power …
... attached peripherals).
The 7805 voltage regulator used inside the ... -
New member, dead SpeccyHallo everyone, I was directed here from a Commodore (boo, hiss) forum after pleas of aid with my newly acquired, quite dead 128k Speccy. I sincerely…
... and found out that the 7805 voltage regulator on the cooling ... -
Want a Speccy Repaired?Maybe it's time to put my 'skills' to use.... Now that I've sourced some of the nastier transistors, I've fixed about 6 rubber keyed Speccys in the …
... power supply failure or the 7805 regulator has gone kaplowie or ... -
Spectrum 128kHi everyone, As a long time Speccy fan weaned on the original +2 machine (hence the username!), I'm thinking about finally buying a genuine Sinclair…
The whole point of the heatsink is to keep the voltage regulator cool (just like the much smaller heatsink inside the 48K machine). Without it, the 7805 should go down the drain pretty fast. -
Powering a SpectrumNow I've got my DivIDE up and running (and it's totally brillant, I encourage [B]everyone[/B] to get one), can I use the power supply from an old PC …
Most regulator (the 7805 in Speccy included) can actually ... -
Any other real Spectrum users in the USA?Hi, I bought a Spectrum +2a off e-bay (I collect old computers) and managed to make it run here in the US. I'm curious; is anybody else running an a…
... pin DIN adaptor with a 7805 in it. It works reliably ... , but the 7805 runs EXTREMELY hot to the ... amps and the highest rated 7805 I could find only provides ... -
"Unknown disk format"-error on Spectrum +3Hi, I have just gotten around to changing the drivebelt in my newly acquired +3. I tried to format one of the 3" disks I bought on eBay the other we…
... indeed to use a small 7805 type voltage regulator. Anything up ... -
How do you get an external tape recorder to work on a +2a?Just for the hell of it, just say the internal cassette player stopped working. What command would you use when hooking up an external player, so the…
... just need to use a 7805 regulator. With one of these ... -
Speccy MTBFHi, Looking at the old (issue 1-2) PCBs, they do look like someone knocked them up in an etching bath/with a soldering iron in their shed but has th…
... of Spectrums in 80-es. 7805 regulator failure was very very ... -
Speccy MTBFHi, Looking at the old (issue 1-2) PCBs, they do look like someone knocked them up in an etching bath/with a soldering iron in their shed but has th…
Cheers for that. I'm a little surprised the 7805 wasn't more frequent as my own Speccy blew two up.....I wonder if there was some other problem like too high a voltage from the transformer...(?) -
Speccy MTBFHi, Looking at the old (issue 1-2) PCBs, they do look like someone knocked them up in an etching bath/with a soldering iron in their shed but has th…
... 's that go wrong, the 7805 being a very reliable device ... -
PC CPU heatsink and fans to cool down Speccy!Ah ha! I've just had an idea! taking apart some scrap PCs I decided to take the CPU heatsink and fan units off and see if I can attach them to the …
... generator inside it is the 7805 voltage regulator; so I think ... -
PC CPU heatsink and fans to cool down Speccy!Ah ha! I've just had an idea! taking apart some scrap PCs I decided to take the CPU heatsink and fan units off and see if I can attach them to the …
... to point out that a 7805 needs more than 7V to ... -
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 …
... same transistors and voltage regulator (7805) as a 48k (it's ... -
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 …
... 're getting 5v off the 7805 voltage regulator.
You ... /datasheets_pdf/7/8/0/5/7805.shtml[/url]
Then ... -
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…
... previous owner only fried the 7805 which will be easy enough ... on screen is because the 7805 is no longer supplying enough ... 're getting 5v off the 7805 voltage regulator.
You ... /datasheets_pdf/7/8/0/5/7805.shtml[/url]
Then ... -
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…
... additionally - although my analogue electronics fu is not all that strong, looking at the schematics for an Issue 2 suggests that the power supply that generates some of the 'weird' voltages (+12v) is a switch mode power supply, which gets regulated by ... -
TV Modulator. Can it be repaired?Is it possible, to repair tha TV modulator (after removing it) if it gives wavy picture? I replaced both transistors (tr1/2) and both electrolytic ca…
... .73V onload.
Voltage into 7805 11.73, with 4.95V ... -
TV Modulator. Can it be repaired?Is it possible, to repair tha TV modulator (after removing it) if it gives wavy picture? I replaced both transistors (tr1/2) and both electrolytic ca…
... power supply - perhaps a weak 7805 that's not regulating properly ... switch mode supply than the 7805, but the upper 32K RAM ... -
+3 external floppyI'd like to connect 3,5" PC floppy drive (NEC) to ZX Spectrum +3 (with diode for RDY). Here are questions: 1) It seems the PC floppy uses just +5V, …
... is to make stabilisator with 7805 and connect input to PSU ... -
+3 external floppyI'd like to connect 3,5" PC floppy drive (NEC) to ZX Spectrum +3 (with diode for RDY). Here are questions: 1) It seems the PC floppy uses just +5V, …
... and you need only a 7805 regulator IC and two 0 ... -
+3 external floppyI'd like to connect 3,5" PC floppy drive (NEC) to ZX Spectrum +3 (with diode for RDY). Here are questions: 1) It seems the PC floppy uses just +5V, …
... and you need only a 7805 regulator IC and two 0 ... -
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…
... Spectrum (well, apart from the 7805 voltage regulator) that gets measurably ... -
5v Transformer.I've got a 5v 3A transformer, would this be ok to use with two 3.5 inch floppy drives?
... better to use a twin 7805 based regulator and power it ... -
5v Transformer.I've got a 5v 3A transformer, would this be ok to use with two 3.5 inch floppy drives?
... meter :D
Two 7805 regs, a bit of vero ... should get some really, the 7805 is used in the Speccy ... -
5v Transformer.I've got a 5v 3A transformer, would this be ok to use with two 3.5 inch floppy drives?
Not well regulated, at least! Most 5v stuff has an absolute maximum rating of 5.25 volts. Unfortunately, 5.4v isn't quite enough to be regulated spot-on by an inexpensive 7805 (which requires a minimum input voltage of 7v)
