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+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) -
5v Transformer.I've got a 5v 3A transformer, would this be ok to use with two 3.5 inch floppy drives?
... certainly won't be. the 7805 will tend to be "iffy ... -
5v Transformer.I've got a 5v 3A transformer, would this be ok to use with two 3.5 inch floppy drives?
... />
The datasheet for the 7805 says the minimum voltage (including ... quite like to use the 7805 rather than trust a power ... the tin (from memory, the 7805 is good for an input ... -
5v Transformer.I've got a 5v 3A transformer, would this be ok to use with two 3.5 inch floppy drives?
Reading the spec on the 7805 my transformers are not up ... -
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 …
... +5v is supplied by the 7805 voltage regulator, the rest by ... -
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 …
... +5v is supplied by the 7805 voltage regulator, the rest by ... 9: 4.98v
7805:
Input: 12.20v ... -
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 …
... easy - it's a common 7805. You can buy them from ... sells components will sell the 7805. They are cheap, and found ... -
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 …
... be able to supply a 7805. In that case, you'll ... -
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 …
... is not fed by the 7805). So keep it *short*. The ... -
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 …
Hi,
There is a good alternative to the heating 7805 ( designed by Sami Vehmaa).
I bought all the components 2 monthes ago... but they are still in the box ! :-D
[url]http://user.tninet.se/~vjz762w/images/ZXREG.jpg[/url] -
TIPP31 transistor questionYesterday I had the time to try and repair a 4S issue 48k spectrum I had. First of all I replaced all the electrolytic capacitors. The tr4 transistor…
... doesn't look like a 7805 reg. Are you sure it ... -
TIPP31 transistor questionYesterday I had the time to try and repair a 4S issue 48k spectrum I had. First of all I replaced all the electrolytic capacitors. The tr4 transistor…
... that might be because the 7805 heat sink is near, I ... -
TIPP31 transistor questionYesterday I had the time to try and repair a 4S issue 48k spectrum I had. First of all I replaced all the electrolytic capacitors. The tr4 transistor…
... that runs entirely off the 7805 regulator. All the other digital ... single 5v supply off the 7805 too. (I've not looked ... -
TIPP31 transistor questionYesterday I had the time to try and repair a 4S issue 48k spectrum I had. First of all I replaced all the electrolytic capacitors. The tr4 transistor…
... final question, for voltage regulator (7805) i used one with the ... -
ULA chipHi. Where i can find a ULA 6C001E-6 chip for an 3B issue Speccy ? Also looking for one 7805 heatsink... Thank
... RWAP or me.
7805 heatsink - for what issue, the ... -
ULA chipHi. Where i can find a ULA 6C001E-6 chip for an 3B issue Speccy ? Also looking for one 7805 heatsink... Thank
[QUOTE=DEATH;187170]
7805 heatsink - for what issue, the ... -
Reason for strange display layout?I have always wondered if there is any technical reason behind the strange layout of the display file or why did Sinclair choose to do it this way?
... can be faster than the "stepdown" function where 7/8 times ... -
Reason for strange display layout?I have always wondered if there is any technical reason behind the strange layout of the display file or why did Sinclair choose to do it this way?
... can be faster than the "stepdown" function where 7/8 times ... ]
Count T-cycles: Stepdown function takes minimum 22T cycles ... -
TIPP31 transistor questionYesterday I had the time to try and repair a 4S issue 48k spectrum I had. First of all I replaced all the electrolytic capacitors. The tr4 transistor…
[QUOTE=gtsamour;187043]
A final question, for voltage regulator (7805) i used one with the indication "L7805CV", is it appropriate?[/QUOTE]
Yes, it this an 7805 regulator from "ST Microelectronics". :-) -
48K Speccy not workingHey, A few months ago (hope it´s not to late) I was loading a game into my speccy and from one moment to another it stopped working! I unplugge…
... plastic square bearing the number 7805 with a metal tab on ... -
128k dead, no TV signalI got 128k spectrum (heatsink model) from a friend of mine. He told me that speccy is dead, and he doesn't know what's wrong with it. When I plugged…
... is also +5V line from 7805 so I guess something should ... -
48K Speccy not workingHey, A few months ago (hope it´s not to late) I was loading a game into my speccy and from one moment to another it stopped working! I unplugge…
... .tkk.fi/Misc/Electronics/circuits/7805.gif[/url]
We need ... of the following:
1. 7805 is dead => replace it ... only pin 3 of the 7805, powering it up (connecting the ... +5V appears on it, then 7805 is good and one of ... -
Unconventional way of diagnosing a faultHi everyone Some time ago I got a 48k Spectrum (issue 3B board) in a pretty bad condition. I believe the power supply transistor TR4 failed, causing…
... enough to blow up the 7805 and blow up the coil ... -
Unconventional way of diagnosing a faultHi everyone Some time ago I got a 48k Spectrum (issue 3B board) in a pretty bad condition. I believe the power supply transistor TR4 failed, causing…
... enough to blow up the 7805 and blow up the coil ... -
Spectrum Diagnostics Board - 25th Anniversary projectWell, I said I'd try and get something online about this by today, and I have indeed done so. This web page still needs finishing off (in particular,…
... couple of transistors and the 7805), wouldn't it be interesting ... -
ZX Spectrum 128+ problemsHello!I recently purchased and got myself a spectrum 128+ from ebay.The item did not have an original power supply so i got a power supply of 9volts …
... VRegs, and does cover the 7805 VRegs used by the 128K ...
