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The rescue of a coil.The problem at hand was a known defect transformer from the switching convertor inside a Spectrum. Both windings are not interrupted and not intercon…
... How to identify a defect coil, as nothing special is ... self inductance, a good coil showed some 50 uH for ... winding of the defect coil showed just some 5 ... real test. Removing the coil from a working Spectrum took ... one takes 3 seconds. 12V measures 11.98, minus ... -
Spectrum +2 grey 12v railHello everyone, I have this grey +2 with no video from tv. After much reading and testing i realized it was the internal power supply. At the 12v ra…
... internal power supply. At the 12v rail to tea2000 and serial ... suspicious thing was the t1 coil. I measured 9.xx volts ... from the same type of coil by touching 2 terminals with ... DMM.
The +2 suspicious coil is in impeccable visual state ... -
Spectrum coilFerrite bobbin, two coils wound on top of each other. Bottom coil is 15 turns, top coil is 36 turns. This is the coil found in the 48K spectrum. Ok…
... each other. Bottom coil is 15 turns, top coil is 36 turns ... . This is the coil found in the 48K spectrum ... /> Ok, I want build a coil to the same spec, using ... bobbins? The rest of the coil construction is simple, it's ... -
+12v/-12v/9v and peripherals?Do any peripherals use the +12v, -12v or 9v lines exposed at the edge connector? Firstly, if they use +9v they won't work on a +3, since the +3 does…
Do any peripherals use the +12v, -12v or 9v lines exposed at ... traces down to pass the +12v/-12v through, so I'm looking ... -
Issue 3B problemHi! I have an issue 3B board that is having a strange problem: when I got it it didn't had the -5V and +12v, as usual. After replacing TR4 and TR5 t…
... 't had the -5V and +12v, as usual. After replacing TR4 ... -5V came back, but the 12V are actually 11.10V... :-?
coil buzzes but I have no ... -
Microdrive using simple coilWhile listening to my iPod using cassette car adapter I came to idea - why not doing the same for the microdrive? Anyone ever tried that? Do you thin…
... ? Do you think a simple coil in the cartridge could do ... 120 kb/s and the coil would produce magnetic impulses to ... -
Replacing coil with other component?The purpose of the coil transformer, from what I gather in the schematics of the issue 2 spectrum, is to create 5V from about 9-10V. Would it not be …
The purpose of the coil transformer, from what I gather ... -
12V -> 9VI found this simple dc-dc converter: [url]http://www.mcrent.com/workbench/dcdc1216/[/url] it converts 12V to 16V, can it be used to produce 9V by mod…
I found this simple dc-dc converter:
[url]http://www.mcrent.com/workbench/dcdc1216/[/url]
it converts 12V to 16V, can it be used to produce 9V by modifying R1 and R2?
is there some better solution? -
+2 coils: a bit smaller, but compatible with 48K coilsThe coils in the +2 seem to be compatible with those from the 48K. Not that strange of course, as all ZX Spectrum models (except +2A, +2B and +3) sha…
... you can see an 48K coil in a +2.
Notice ... feed the +2 5V and 12V directly, e.g. from a ... -
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…
... /> I do however have a 12v 2amp PSU, if I reverse ... -
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 …
... attention is drawn to the coil. Continuity-wise - it checks 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 ... -
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 ... a wire on the inductor coil was broken! So I desoldered ... -
128K Toastrack - Missing coil?Hiya! I recently acquired a fleabay 128K, and before putting power through it, I thought i'd open it up to see if anything looked obviously wrong (e…
... it was missing the massive coil that sits in the circle ... have one? Is it the coil I've read about that ... -
Joytsick Interface damaged SpectrumHello All, Sob.. I am a plonker, I did the cardinal sin, I was testing a bunch of joystick interfaces that I got off ebay and one didn't have the ke…
... I have lost -5v and +12v. Does this mean the lower ... now toast?
My coil has some modification (done prior ... two outer pins of the coil. A second modification goes to ... bottom inner pin of the coil. Does anyone know what this ... -
12V Rail - Spectrum 48kOkay - I may just be having a senior moment here, but I'm running out of ideas. I'm working on a Spectrum Issue 4S board,and have had to remove al…
... -5V are fine, but the 12V rail is at almost 25V ... , and the rail there was 12V as expected.
Has ... -
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…
... on and measured the voltages, 12v was giving me an extreme ... on with the ram removed. 12V line was fine with a ... the picture. Looked at the 12v line and there is a ... lower ram ic's the 12v line is ok but when ... causing the instability in the 12v line, it's ruining the ... -
Spectrum issue 4SI have an almost completely depopulated issue 4s board. Wondering what to do, repairs or spares? I hooked it up and the voltages are off, 5v is fi…
... about 0 I think and 12v is somewhere around 4v or ... fine and so is the coil, any suggestions? -
Toastrack - faint monochrome displayHi all, I've got a Toastrack with a video issue on both RGB and RF. I get a faint monochrome screen: on one LCD display it is predominately white,…
... 'm getting about 2V, not 12V, so this is the likely ... to think that either the coil that is the issue, as ... -
Issue with TV signal + Inductor Coil (16K Issue 2 Speccy)Hello guys, I just got a 16K Issue 2 Speccy from eBay. It was sold as not working so I knew there would be some work needed before it's working ag…
... to be with the inductor coil which gives me +9V on ... -
48k Issue 6a Very sick indeed.Hi Guys. I have a 48k Issue 6a board that shows a white screen with grey border. The white screen has three black squares spaced equally on the le…
... right there? Also, the coil has also been replaced at ... Both the LM1889N and coil I will remove and replace ... hear any whine from the coil.
My ... 7mV, 5V = 4.96V and 12v = .908V. I know that ... the previous LM1889N and coil jobs and report back.< ... -
ZX Spectrum Issue 2 - 12V badHey there, I'm currently attempting to fix a ZX Spectrum issue 2 that I recieved. Overall the machine was generally working when I recieved it, bu…
... vertical lines. Turned out the 12V line is bad (along with ... (eliminating the need for -5V/-12V) according to this http://www ... cathode of D15 and feed 12V with a second PSU. However ... D15 soldered in place, the 12V line gets ~8.4V-8 ... -
Sinclair 16k Ram pAck Issue3 schematicsHi guys, I am willing to repair a 16k ram pack for the ZX81 but I cannot find any schematic of the ISSUE 3 ram pack. I could only find a schematic…
... have is probably a bad coil as I saw the magic ... I am missing -5V and +12V. I would like to get ... -
12V missing on an issue 3I’ve been working on an issue 3 Spectrum +. It shows thin distorted vertical stripes on bootup. +5 and -5V are all right but the 12V line measures ro…
... are all right but the 12V line measures roughly two volts ... the other place that uses 12V is the LM1889, which is ... -
zx spectrum +2A power supply missing -12v voltshey.. i'm looing at a zx spectrum +2A power supply that the -12v rail seems to be missing .. it has the 12 volts and 5 volts .. it is the version wit…
... +2A power supply that the -12v rail seems to be missing ... ok, i have changed the -12v regulator (79L12) no change then ... to the 5 volt and -12v rail ,,, confused.com
i ... realize that the -12v is not strictly required for ... -
is my ZX Spectrum + finished :(When i turn it on the screen i get the usual gray border all around but in the screen area i get yellow and some orange lines with a black background…
... , ULA, coil and voltage regulators transistors for the -5V and +12V are ... -
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…
... remember, and it does need -12V to work, but the rest ... words, the computer should work, -12V or not. However, one thing ... , else you'd get the -12V.
How are you ... a buzzing noise from the coil, but that's about it ... -
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…
... remember, and it does need -12V to work, but the rest ... words, the computer should work, -12V or not. However, one thing ... , else you'd get the -12V.
How are you ... a buzzing noise from the coil, but that's about it ... -
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 …
... again. This will eliminate the +12V (22A) line.
Check ... the primary side of the coil, and eventually into the base ... -
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 …
... RAM. +/- 5V and +12V. If not, check the coil, ZTX650 AND the ... -
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…
... RAM. +/- 5V and +12V. If not, check the coil, ZTX650 AND the ...
