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Lower Memory - Why Multiple Voltages?Having spent much of the weekend working on getting my old Spectrum working, my Dad (who is visiting) and I were chatting about the schematic. Given…
... , supplied the whole machine with 12v to run the LM1889 and ... -
+3 Floppy drive helpHi guys, I recently found my old spectrum gear and started to see if it all still works, now i had/still have a floppy disk system - Thurnall disk d…
+3 stereo mod againIs there a way to get stereo audio without cutting any traces? BTW, I don't understand why two pins are used for +12V on DIN connector. one of those…
Is there a way to get stereo audio without cutting any traces?
BTW, I don't understand why two pins are used for +12V on DIN connector. one of those would be perfect for stereo.+2 (Grey) and AT/ATX PSUAny ideas on the best way to power a grey +2 board from an AT or ATX PSU? Looking at the schematic, I could do this one of two ways... 1: Bypass th…
... with connecting it straight to 12v and making the regulator get ...Speccy PSUI've grabbed a Speccy PSU from fleabay and it looks like a Speccy Plus PSU. After testing it with a multimeter it's kicking out 12V rather than the …
... multimeter it's kicking out 12V rather than the 9V I ...ZX Spectrum Hardware Standards stickyHi I would like to propose that we add a ZX Spectrum Hardware Standards sticky. I should contain all the voltage, current, power and frequencies st…
... range of the +5, -5, +12V of the power supply, power ...48k Issue 4A power supplyHi, I just repaired a 48k Spectrum+ with an Issue 4A board. The computer worked but the picture was mono with bad contrast and bad synchronizing. I …
... /> I found out that the 12V where only 1.7V and ... types and therefore removed the 12V and 5V from the Rams ... . So only the 12V where needed for the color ... capacitor C44 was cut from 12V output of the transverter. After ...another faulty zx spectrum +2 to fix!!!Hello to all, I'm new here... I have got a faulty +2 (gray) and start to try fix it... I have read the treads of xaris_sm and Pluto63 as background…
... the ZX i found that 12V aren't present... the ZTX650 ...Issue 3 board... How to resurrect?Dear Everyone, Now I have a working 48k Issue 3, a sort of working Speccy+ (still having problems with the keyboard, more of that in another post) a…
... right side of zero)
12V pin: -0.001V (that surely ...Spectrum+ Noisey Picture ProblemHi fellow Spec-chums I need your help! I've recently brought a 48K+ Spectrum(issue 6A) that I'm trying to repair. I did all initial tests on it prio…
... read online this was the 12v line that the feeds the ...Spectrum +3 PSU questionCan I use a +2A/B PSU to power a +3? I noticed the +2 is 12v@200mA and the +3 is 12v@700mA so I thought I'd ask you lot if it will work before I fry…
... /> I noticed the +2 is 12v@200mA and the +3 is ... 12v@700mA so I thought I' ...ZX spectrum 128K + 2 (Grey one :)Hi all, I'm trying to revive a dead ZX 128K +2 (the grey one). The regulator was damaged and seemed to be feeding 7.8Volts onto the pcb. Yikes ! I…
... is not getting it's 12V and I suspect if it ... . I thought without it's 12V it would just not function ... area to ensure the -5/12V came up and then proceed ...+3 on GT65I got the green Amstrad monitor GT65 and I was wondering , it can be connected to the spectrum +3, completely (power supply and video)? I saw that th…
Spectrum Missing -5vMy Spectrum is "almost" booting, just when you expect the (C) 1982 Sinclair Research to appear it just displays flashing squares on the screen :( I …
Interesting 48K failureI thought I'd recount a failure I've not seen mentioned before that I saw tonight while fixing a 48K issue 6 board. The background: The initial fail…
... 's right next to a +12V pin on the edge connector ...Issue 3B suddenly goes black and whiteAnother 3B I have here had a faulty ULA, swapped that out for another and hurrah! Works! New keyboard membrane and composite mod later I load a game…
... (on pin 12 I think) 12v present. Im a bit stumped!Fixing my old ZX Spectrum 48K issue 4AHi Guys, I trying to fix my old Spectrum 48K. Looks like my dad used a wrong power supply as the ULA had a bit missing and so did the 7805. So I rep…
Spectrum +2 (Grey version) RGB SCART QuestionHi Guys, A quick question for you. As the new owner of a 128K Spectrum +2 (grey version), I'm using a cable from Retro Computer Shack which tries to…
... can be reconfigured to provide +12v down pin 5 of the ... not entirely sure where the 12v is coming from and whether ...Issue 4S differencesI decided to buy an Issue 4S PCB after reading much about them on here. It was originally in a plus case which didn't come in the sale. I've been run…
... I expected to be. The 12V and -5V power supply is ...Sinclair 128k available?Hello there, Spectrum fans! Let me introduce myself. I am from Russia, my name is Dimitri. In the 90-s I was working for a firm producing ZX Spectru…
... to melt them, probably feed 12v instead of 5v or something ...Harlequin - usefull mods and addsHello, I start here a thread regarding mods and adds for the Harlequin. It was found: * that the Sinclair Interface 1 does not fully work at the Ha…
... 5V at B20 and the "-12V" (indeed it is a ... voltage to be directed to -12V) at B23 especially for ... -DC-Wandler from 5V to +/-12V (2 x 82mA) (type: ... a 79L05 regulator reducing the -12V.
Each of the ... Spectrum but leads the -12V of the harlequin to the ...populated Harlequin Rev.D -> Rev.FHi, I like to sell my Harlequin Rev. D board. I modified it to be identical to Rev. F: * switching regulator instead of linear regulator for DC in …
... at SCART output
* 9 ... 12V at pin 8 of SCART ... needs about 100 mA at 12V DC input.
[IMG ...ZX Spectrum 48K Issue 3, loss of -5V rail.Hi all, I've googled this problem and poured over the electrical diagrams for the circuitry concerning the power supplies and I believe I know what …
... out fine. However, I have 12V on one side, and -1 ... should be. The diagram suggests 12V on one side, but suggests ... 100K ohm resistor drops the -12V to -5 and the surrounding ...Can someone help me...Hey all Well after my second complete cock up off ebay I'm feeling pretty deflated now regarding spectrums... First one I ordered was a +2A which h…
... running it on a AC 12V adaptor...
Anyway, the ...What is this disk interface (and how to use it)?Anybody seen this floppy disk drive interface before? It uses an MB8877A and the rest is 74XX-logic, no GALs/PALs. And an EPROM. [IMG]http://i1373.p…
... , what seems needed is just +12V and +5V. It looks like ... the 12V is also fed through 2 ...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…
... 5v going to it. The 12v is also absent from the ... 12v rail. I was thinking along ...Pictures of 48k ZX Spectrums Showing the Important Voltages[SIZE=6][B]Pictures of 48k ZX Spectrums Showing the Important Voltages[/B][/SIZE] [URL="https://farm4.staticflickr.com/3841/15005543009_7bcf3b3031_o…
... be between +8V and +12V
[*]The +12V (for the "lower" 4116 ... +11V and +13V
[*]The +12V (for the LM1889N colour encoder ...How important is the 9V line?I'm in the middle of resurrecting an Opus Discovery. The transformer is gone so Im using a small switched mode PSU from a PC. My plan is to bypass …
... rectifiers and LM317 regulators with 12v and 5v feeds. However, the ... Spectrum, can I use the 12v input to feed the 9v ... way be to reduce the 12V to 9v? Would some diodes ...
