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Homebrew keyboardGuys, just a quick question. I really should know, but I don't :( I've built keyboards for the standard layout before now, and was hoping to expand…
... voltage drop across a silicon diode, and b) will the ROM ... Shift key.
The diode voltage drop I can sort ... -
Opus Discovery OddnessHi everybody, I'm busy trying to repair an Opus Discovery for a customer. It's proving to be quite frustrating. First off, the LM317T regulator fo…
... what I presume are the diode bridges BR1 and BR2, but ... -
Spectrum +2 power supply replacementI bought my first Spectrum the other day, a grey +2, but it seems that the power supply is busted (I've tested it with a multimeter and tried replaci…
... work, if I reverse the polarity so it's centre negative ... -
PlusDlite problems with 128K modelsLast year I developed the PlusDlite, and already shipped out a couple of them. Only recently I discovered some problems with 128K models. I remember…
... can imagine because of the diode, the voltage level (2.6V ... -
12v in a Spectrum +2My Speccy 128 +2 requires a 9v 2.1a PSU, all my 9v PSU's are much below 2.1 amps :( I do however have a 12v 2amp PSU, if I reverse the polarity so t…
... PSU, if I reverse the polarity so that negative is on ... -
DivMMC EnJOY! I do enjoy!!!!!Hi all! Ok, so I grew up in the UK in the 80?s and convinced my parents to buy a 48k Spectrum ?to help with homework? lol. Well now I am older and ha…
... has now got the correct polarity. ( inner being negative, outer positive ... -
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…
... has to be soldered a diode (1N4007 or similar) parallel to ... that the anode of the diode is at the minus pin ... of C1.
This additional diode does not change the behaviour ... -
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 …
... connector (Rev D has same polarity as at CPU)
* smooth ... -
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…
... the right leg of a diode that sits on top of ... /> The middle leg of the diode attaches to the middle pin ... /> Does anyone know what this diode is for?
Using an EPROM in a 48K SpectrumThere are plenty of guides as to how to do this floating around, however I didn't like the fact that you can't then plug in the standard 27128 ROM ch…
... 's a shot with the diode/resistor circuit installed, so if ...ZX Spectrum+ DivMMC EnJOY! Grundig 16" LCD TV and books.The Spectrum is in very good condition. Composite video mod. New mambrane (bought in November 2014 from rwap_software [url]http://www.sellmyretro.co…
... to output socket with correct polarity.
- Replaced DC input socket ...Grey +2 - DOA and no power lightTook a punt on a grey +2 at the weekend to be a spare. It was "untested" although so were all my other +2's which are all fine. Tried to power th…
... ? Perhaps someone stick the wrong polarity in it or something? Any ...Help: Not loading anythingBought a ZX Spectrum +, having some problems with it. The ear is not working at all, not even a searching tone (not sure of the correct terminology) …
... I have done. Replacing D9 diode (will soon as possible), if ...ZX 48K power plugHi! I'm a newbie, this is my first post. I have a ZX Spectrum 48K, which has been lying around for ages. Its psu lacks a plug. The Psu is 9v and 1…
... need has to have 'revesed polarity'.
Do any of ...48K Issue 3B ROM to EPROM methodsHi folks, While fixing up a completely dead Commodore PET I needed a way of testing the 4116 RAM chips that make up its 32K, some googling found a…
... ROM - EPROM replacement, either the diode+pullup resistor method using the ... have an idea WHY the diode+resistor approach won't work ...12V ripple with lower ram installedI repaired a speccy this week. Before doing anything I replaced all caps and measured the transistors in the power section. When doing this I found t…
... section and found one failed diode (can't remember the number ...Issue 2 48k Yellow DisplayHi guys. As the title says, I have an issue 2 that's displaying the typical yellow/green colour screen at switch on. The picture is clear and stab…
... good. Installed in the correct polarity.
TR4 TR5 removed, checked ...Issue 2 48k Yellow DisplayHi guys. As the title says, I have an issue 2 that's displaying the typical yellow/green colour screen at switch on. The picture is clear and stab…
... good. Installed in the correct polarity.
TR4 TR5 removed, checked ...No CLK on issue 2 ULA pin 32I'm trying to fix an issue 2. The symptoms are as follows:- Black and white bars on screen, colours near impossible to tune in, although these po…
... and starting to suspect the diode at D14 coming into play ... like a resistor not a diode. see post below.
How to connect universal PSU?A fleamarket find! Spectrum+ without PSU. :) I don´t know if it works. I have universal PSU, please confirm which is the correct polarity? [b]A)…
... confirm which is the correct polarity?
[b]A ...No Keyboard after recap - ZX Spectrum 48kGuys I am desperate. I did a recap of the ZX 48k board and now the keyboard is not responding to any keypress :-(. I paid attention to the capacitors…
... paid attention to the capacitors polarity of course and used sometimes ...no sound from speaker when trying to load games from tape and games are not loadingcould this be a blown component like a diode or something? it must be something simple. any help would be appreciated as im sure it wouldnt be that h…
could this be a blown component like a diode or something? it must be something simple. any help would be appreciated as im sure it wouldnt be that hard to fix.Tracking down a favourite Spectrum Adventure gameHello everyone - a new joiner here - looking to pick the collective Hive mind. I was an avid Spectrum gamer, and owned one of the very first 48K e…
... 40 years!! I remember I diode;t complete this game, but ...Bit of fun - one change onlyI also posted this on another marque's forum (for their products) to see. Its just a bit of fun really. OK, if you could of made one change to a S…
... "a reset switch" or "reverse polarity protection", but after a bit ...The trials and tribulations of the external tape recorderAnd you may find this a strange topic, because having been a +2 owner for the last 31-and-a bit years, it's not something I've had to deal with in th…
... -millimetre between utterly inaudible and diode-splittingly deafening.
This ...Finding a good (UK) external switch mode power supply for the basic 48k and 128k ZX SpectrumsThis idea has probably "done the rounds" by now . I think I have heard about it a bit late . This thread with look at replacing the original "heavy l…
... quality one with the right polarity . I am hoping that as ...zx spectrum 48k low -5volt raili have just received a 48k issue 3. initial tests show that all voltages are there but the -5V rail is only showing -4V. it does boot but i have tur…
... it worth changing the zener diode? maybe bad lower ram chip ...General PSU repair guidesNot Speccy related. I'm just looking for a guide as such as to where to begin with a power supply repair. Realise this is a bit of an odd thing to as…
... the mainboard even a tiny 'diode' size one, unless its a ...doubt about swapping ULA in an issue 2 boardIs it possible to swap a 6C001E-6 ULA type with a 5C112E ? I have this issue 2 board that is not booting, it shows me a black border with horizont…
... , the working machine has a diode/resistor mod on the Z80 ...
