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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 …
... short circuit)
The COIL between TR4 and TR5 (does it look / smell ... voltages are present before the TR4 blows. Check one at a ... />
I replaced tr4, tr5 and the coil but tr4 keeps blowing.
I ... question, can i use the coil of a +2 gray spectrum ... -
Spectrum 48K with a thyristor PSU possible?Is it posssible to use a Spectrum 48K with a thyristor switched PSU? I have a PSU with a thyristor, 4 diodes, one electrolyt capacitor, some resistor…
... the schematic for a small DC/DC-converter.
Not to be confused ... to use (and make) one coil... -
Issue 2 voltage troubleDear all, I got my hands on an old issue 2 from a friend. Price was close to zero so I did not hesitate to take it. After powering it up I was sur…
... :
[LIST]
[*]TR4 or TR5 [I]almost[/I] dead to ... .
[*]Shortened turns in the coil, such that the voltage swing ... just go ahead & replace TR4, TR5 and electrolytic caps.
Colour blocks on displayHi all, I have just acquired another Sinclair product, my first one being a C5, it's a 48K ZX Spectrum. It shows colour blocks on the display when p…
... a problem with the voltage converter circuit or power supply connections ... of the Issue 2 voltage converter circuit failing. If that has ... possible one or both of TR4/TR5 have failed. Carefully note the ...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 …
... is clearly something wrong if TR4 fails.
You may ... drawn from one of the DC-DC converter's outputs; either a failed ...RECOM pin compatible DC-DC 7805 regulator replacementsFinally got myself sorted out now. If you want to purchase chips send me an email to [email]alistair@alistairsserver.no-ip.org[/email] with your payp…
... 's still the board, caps, coil + shipping. So I don't ... to order more than that DC-DC converter.48k + Spectrum Issue 4S Display IssueHi all! Brand new user here. Growing up I had a zx spectrum for a little bit, and recently I have bought a working 48k + Spectrum (Issue 4). I was…
... br />
It seems the DC-DC converter is basically working as -5V ... buzzing noise from the inductor coil (though you may not ... waveform of the output inductor coil will be coupled straight ... coil itself or something wrong in the feedback part of the converter ...Issue 4A repair attemptI think I need some help. I have a nice Issue 4A main board here, which does not give out any video signal. I checked some voltages (the ones that se…
... regulator, the coil, the entire lower RAM and TR4/TR5 all show expected ...Issue 4A issuesHi all, I've been trying to get the Issue 4A board that came DOA with the case I purchased for my Frankenspectrum to work. I've recapped and socket…
... , 7805 and coil swapped out, and TR1/TR2/TR4/TR5 swapped for spares ...Almost no picture on a toastrack Issue 6UI?d need some help with a toastrack, that hardly shows any picture on both the RF and RGB. It?s totally distorted. I had this before and I remembered…
Best to renew the electrolytic capacitors in that area, recheck TR4/TR5, then check the coil if all else fails?
BFixing 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…
Hmm, TR4 shouldn't be running that ... oscillation circuit formed by the coil/TR4/TR5.
BFixing 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…
[QUOTE=balford;776165]Hmm, TR4 shouldn't be running that ... oscillation circuit formed by the coil/TR4/TR5.
B[/QUOTE]
Help put this back to 16kSo this issue 2 arrived today and ive opened it up just to nosey and confirm that infact it is an issue 2. Now from the help offered in an earlier po…
... the condition of TR4 & TR5 and the inductor coil. Replace any components ...Next step for fixing my speccy?Hi guys, I've picked up my faulty Spectrum aiming to fix it. So I followed the excellent JouledperCoulomb videos on Youtube for the basics and I am …
... - this means the voltage converter circuit based around TR4 is fine. Since ... volt. At this stage, replace TR4/TR5 if you don't get ... , check the associated circuitry around TR4/5 as the Zener diode ...Next step for fixing my speccy?Hi guys, I've picked up my faulty Spectrum aiming to fix it. So I followed the excellent JouledperCoulomb videos on Youtube for the basics and I am …
... - this means the voltage converter circuit based around TR4 is fine. Since ... volt. At this stage, replace TR4/TR5 if you don't get ... , check the associated circuitry around TR4/5 as the Zener diode ...Faulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
... have no buzz from the coil (sick Spectrums with bad voltage ... they don't make the coil resonate - a Spectrum should have ... buzz).
1) Change Tr4/Tr5
If that doesn't ... joy:
3) Change the Coil and Tr4/Tr5 again.
If ...Faulty 48+ Help NeededHi, This is what I get when I plug in the spectrum, this is tuned in. Vid shows a reset. Any ideas, or pointers on the first thing to check. Keyboa…
... have no buzz from the coil (sick Spectrums with bad voltage ... they don't make the coil resonate - a Spectrum should have ... buzz).
1) Change Tr4/Tr5
If that doesn't ... joy:
3) Change the Coil and Tr4/Tr5 again.
If ...'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
TR4, TR5, a coil, a power socket, an sr10s05 regulator and some capacitors ordered... exciting! :D'Interesting' Issue 2 modSo I've been lurking on this forum for a while and I've got to the point where I want to see if I can repair a speccy.. so I bought me a 'broken' one…
... mode power supply circuit (TR4, TR5 and the coil etc.).
Also ... the state of TR4, TR5 and the coil. If TR4, TR5 or the coil is faulty ...ZX Spectrum upper RAM module (4532/4164 replacement)Following the [URL="http://zx.zigg.net/LRR/"]lower RAM replacement module[/URL], there have been quite a lot of requests for something similar for th…
... +5 to +12v dc-dc converter fitted and the Speccy coil removed (disabling the ...Short Circuit Damage?Hey Spectrum fans, Currently trying to diagnose what is wrong with my 48K Issue 4B ZX Spectrum. The initial problem was the fact it would not boot -…
I always change TR4 and TR5 at the same time, as if one is bad it can take out the other.
The official advice is originally to actually change TR4, TR5 [i]and[/i] the coil, but that may be difficult these days!Smokin... more 48k woesHi, it looks like I've converted another Spectrum 48K+ into a smoke machine. I'd been rebuilding an Opus Discovery unit and everything looked good. …
... voltage inverter formed by TR4, TR5 and the coil, the voltage on +12V ...Cooking toastrack... the dreaded smellI powered up my Spectrum 128 (heatsink model) yesterday only to see what looked like an out-of-tune picture on the television. I'm using a scart adap…
... refer to the coil, is that the little coil next to the ... , it's right beside TR4/TR5, and marked 'COIL' in your photo above ... four corner pins of the coil. Test both left hand pins ...Spectrum 48K Ferranti ULAIs there anywhere to get hold of the ICs in the subject? Martin
... or with the DC-DC conversion circuitry (primarily the TR4/TR5 transistors).
Then replace TR4/TR5, see if all voltages are ...not working issue 3Hi all, I received this mobo from ebay, after start i have this on screen [img]http://forest.no-ip.org/wos/issue3_01/20150728_135908.jpg[/img] …
... in the voltage converter circuit have failed, though TR4 is by ... the diodes in the voltage converter circuit too.
... new transistor you fitted for TR4 has burnt out, unless ... /> - Check TR4, TR5 and the diodes in the voltage converter circuit.
another non working issue 3 48kHi all, next! :) I don't have good filings about this speccy :) https://youtu.be/D9qpCR18-kI here is short video what this speccy do. we hav…
... , but is the inverter working (TR4 & TR5), or is the +12V ... the secondary winding of the coil?
Other causes of ...Power issues on a 6A 48 K SpectrumHello all! I decided to take another look at my 6A Spectrum that I broke via a bad joystick adapter, I’ve removed the bottom 16K ram and replaced…
Sisce you did change TR4 and TR5 "to no avail", I assume ... power supply section, and specifically TR4, TR5 and coil, are working properly. Stop ...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,…
... difference with new transistors in TR4 & TR5. I put in sockets ... same result applies - TR4 keeps popping and TR5 is unscathed.
I'll look to disassemble the coil ...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…
Swapped TR4 with a ZTX653 - Speccy is ... the 7805 with a Traco DC-DC converter and removed the heatsink. Now ...Faulty ZX Spectrum 48kHi guys, I just got around to doing a composite mod on an old ZX Spectrum 48k that I got from Ebay a while back. It did say it was untested and b…
... ). I am sure that the DC-DC converter doesn't work at all ... a high chance that the TR4 has been "cooked". It is ...
