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VCF report and photosNot sure where to put this, exactly...but here it is, what went on at the Vintage Computing Festival at Bletchley Park last weekend. Finally I've fo…
... was wrong with it was TR4 was dead and the keyboard ... -
ZX Spectrum + Issue 6A Repair attemptHello everybody! I got ZX Spectrum + which doesnt work properly. On power up I can see color mosaic, then paper goes black and i can see thin red ba…
... are good (i replaced LM7805,TR4,TR5), so I suspect upper ... -
Do ULAs die?Thought I'd start this thread as people often think their ULA is dead, when it's actually the RAM or power circuits. Searching the forum in the futur…
... memory and/or the powersupply TR4.
Does anyone categorically ... -
Fuzzy Screen On 48k Spectrum.Hi there. I bought a Spectrum off eBay last week (another for my collection lol), and it suffers with a fuzzy screen e.g. it looks like interference …
... & c25 and changed transistor tr4, but it's still the ... -
ZX spectrum +2 issue3 (gray) videoout problemHi! Have distorted flickering image on ZX spectrum +2 gray issue3. RGB connection thru sony CXA rgb->svideo coder (Good quality! but flickering) [ur…
... ]
Test connection to transistor TR4 (composite)
[url=http://img513 ... -
Newbie question about my unwell Spectrum...Hi - I have had a couple of dud 48K Issue 3 Spectrums in the loft for 20 years or more. One would initialise sometimes but could not be guaranteed t…
... has been fixed by replacing TR4.
The second machine ... -
Hi everybody! Need help trying to rescue a ZX 48K...Hi, since this is my first post, a bit of info about me: I'm an Italian guy, now living in Poland (Warsaw), informatics and electronic geek since…
... bit too low (around 8v). TR4 was the culprit, yesterday I ... -
Amperage drastic reduction in a rubber 48KWell, I am now with the approach of a drastic reduction ZXSpectrum amperage. As a first step would change the Z80 processor for other (Z80C). Unfortu…
... by the TRACOPOWER 2150, change tr4 by the ztx651 and possibly ... -
Amstrad Toast Rack?Hello there my fellow WoS'ers Recently I have been very lucky with my brother giving me a Sinclair Spectrum 128K+ (Toast Rack), it needed a little a…
... ... the board is a 1985 6U board
(click to ... -
ZX Spectrum + alive thanks to this site.I was given a dead unit several months ago. I finally had time to look at it yesterday. Using the repair guide on this site the thing is now alive.…
... . One 7805 and one ztx650 tr4 and it is all good ... -
Spectrum + and +3 Bath! Including SEXY photos!Continuing my "bath" projects: Today I repaired a 48K Spectrum + to working condition, an Issue 4 that is nice and stable. Took 4x Spectrums+ apart …
... /> Here is the PCB, version 6U (never heard of such a ... -
Help with Spectrum 128k reparationHi! I have the following symptoms with a 128k unit version 6U - On power on, black and white bars (one char width each), white background - Once po…
... with a 128k unit version 6U
- On power on ... -
Toko 7KL coils?Hello, These are the coils found onboard 128K spectrums Version 6U. Its not the coil used in the power cirquit. They are used on the picture generat…
... found onboard 128K spectrums Version 6U.
Its not the coil ... -
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…
... itself by a blown transistor Tr4. This means that too much ... direct current has gone through Tr4, and therefore also must have ... -
Repairing another Issue 2 48K Spectrum.I said at the start of the other thread that I've got another one of these and I've started investigating it. The board is more-or-less exactly the …
... PSU.
I changed TR4 for a new ZTX651 and ... . The PSU limiter operated and TR4 became warm, hopefully it hasn ... is causing excessive current through TR4. In circuit, the mini-transformer ... -
BeginnerIm having a go at fixing a spectrum which has been in the loft for 20 years and would like some advice please.... I have downloaded the 'spectrum se…
... to do is to change TR4 ZTX650?
Would I ... -
Grey +2 video output and oddities.I've been experimenting with one of the above that I acquired years ago, but had just been buried at the back of a cupboard. I've connected it up to…
... 't synchronise with it. Transistor TR4 seemed to be installed incorrectly ... -
ZX Spectrum not working... issue 4S?Hi, I've bought a "new" broken ZX Spectrum +. The idea was to put an harlequin board inside, but for the moment I'm trying to put it in working order…
... I'll try first changing TR4, TR5, C44 and C45 (as ... -
Issue 4S users... I need your help!Short story: Issue 4S spectrum don't work. TR4 seems to have pins at different places from other speccys (BCE versus EBC), and usual replacement part…
... 4S spectrum don't work. TR4 seems to have pins at ... transistors have this boards at TR4 and TR5, as they seems ... -
Difficult to find upper RAM fault.I've recently repaired an issue 3B 48K Spectrum that had a tricky to diagnose upper RAM fault, so I thought I'd post a report of what I found here. …
... identified and replaced a faulty TR4 and 7805 (that had become ... -
Issue 4S Schematics and DC-DC circuitA while ago I bought a Spectrum 4S that had problems tuning. I removed the RF tuner as I was not going to use it and did the composite mod. It worked…
... was very noisy. Then suddenly TR4 blew up, and I am ... zx a mere seconds before TR4 blows. -
Issue 3 power problemHi all, I have an issue 3 board with an odd power problem, I have no -5V in fact, measuring the voltage on this line leads to a surprising result : …
... are dead, and have replaced TR4 & TR5, as faulty RAM ... .
It think the TR4/TR5/L3 circuit must be ... -
Spectrum+ and dead keyboardI have a Spectrum+ which had no picture just snow on TV. I found instructions, that it might be regulator 7805, so I changed it. Now I saw something …
... that now try to change TR4. I did
it and ... -
Replacing ZTX650 with BD139Today I blew up one of the GALs on one of my DivIDEs while testing on my Toastrack. Shorted M1 with 12V and the 12V circuit broke. I had to replace T…
... .
I had to replace TR4
First transistor I tried ... experience with the BD139 replacing TR4 in this circuit ? -
Help me resurrecting a 128KHello to everybody. I'm really struggling along a repair of a standard 128K a friend of mine handed me over some (ok, actually a lot of) time ago. A…
... 's a very clean Issue 6U. The symptom is the standard ... -
The great 128k ConversionWell, I am not sure if it is going to be great. Hopefully it will! This evening, I set about getting my Issue 6A Spectrum Plus working. I suspecte…
... first job was to remove TR4 and TR5. I had already ... a cupboard.
Putting TR4 and TR5 on a transistor ... that TR5 was Ok, but TR4 had a short across one ... -
Issue 2 video problemHello all, Need some help with an issue 2 board that I 'm trying to restore. I've replaced all the electrolytic capacitors, changed the voltage regu…
... capacitors, changed the voltage regulator, tr4, and a Zener and the ...
