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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 ... -
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…
... transistors are located near the coil, so at a different location ... -
Timex Compute TC2048 loading problems solvedHi everybody, I've just finally fixed a TC2048 that had numerous problems. Once I'd changed all the RAM, the CPU and the ULA (surface mounted, for a…
... /> Change the ZTX750 by the coil, though, and you get a ... -
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! -
TEA2000 mod for better CVBS quality?Has anyone tried this before? :confused: [URL=http://s1063.photobucket.com/user/JRT480/media/Evenmoreperfect_zpse2505ab9.jpg.html][IMG]http://i1063…
... with various values for the coil and the ceramic capacitor and ... * that a 15~18 uH coil and a 47pF ceramic capacitor ... -
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 ...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 ...'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…
... /> [*]Regulator & Heatsink
[*]The Coil
[*]C47 capacitor
[/LIST ...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 ...Dodgey R62 / D16 on Issue 2?Hello all, I am still beavering away trying to work out why my Issue 2 fails and after a much closer visual inspection I noticed what looks like som…
... the current from 9v to 12v, however when I performed resistance ...ZX Spectrum +2 (grey case) voltage converter circuit oddity.I'm working on repairing one of these and have encountered a possible problem and I'm not sure what I can best do about it, if anything needs to be d…
... />
Good Spectrum: 12V -> 11.3V ... -12V -> -12.4V
Spectrum under repair: 12V -> 11.7V ... -12V -> -13.9V ... only thing that uses the -12V supply). Removing IC3 lowers ... particularly hot. The reduced 12V supply still seems to be ...Issue 1 oddityHello to everybody, I have a very first under my hands - a broken Issue 1. Apart from the classic "broken lower RAM" syndrome which will be easily t…
... I can tell.
+12V is operative after the obvious ...Issue 3 ULA ProblemsI've been given an Issue 3 48k to fix. It was producing no video and no picture on the TV. The coil was buzzing so it was getting power and all the v…
... picture on the TV. The coil was buzzing so it was ...New Floppy Interface for the +2a/b (black case)Hello everybody! For a long time I wondered about the posibility of adding a FDD to the +2a/b (black). I knew it was possible; All the logic is alre…
... floppy drives that uses the +12v line unless you have a ...TR4/TR5 replacementHi guys, I've got another Spectrum I'm working on now - an Issue 4S this time. When I originally got it, I powered it up and did the basic tests a…
ZX Spectrum issue 6a - yellow border problem<p>Hello!</p><p>I have problem with my Sinclair ZX Spectrum issue 6A, 48K. </p><p>I have changed low memory (all 4116 IC's) and coil, all electrolyti…
... (all 4116 IC's) and coil, all electrolytics capacitors, TR4 and ...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] …
... good :) I don't have 12v and don't have and ... after this i get back 12v but not and this time ...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…
... speccy do.
we have 12v and 5v and don't ...48k not startingHi team, I have 2 48k's, one works (Issue 4s), one doesn't (Issue 4a). The non-working one appears to start, but not finish the RAM test. The pape…
... .5V out. -5V, 5V and 12V are all present and within ...No colour - Issue 2 SpectrumThis one is driving me mad - any suggestions appreciated. I have an issue 2 Spectrum with no colour at all. I found the 12v rail was at just over …
... at all. I found the 12v rail was at just over ...Another hardware question - lower 16k bad?Like in my last question, I am referring to this video from JoulesperCoulomb (https://www.youtube.com/watch?v=IzgCmldm2H4), this time, it is with the…
... is with the lower-right (12V) resistance.
The video ...
