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Spectrum & ZX81 PSU Strange VoltagesHi all I've just refurbished my ZX spectrum PSU after i accidently broke one of the wires i soldered the joints to the PCB nicely and all seems to b…
Hi all
I've just refurbished my ZX spectrum PSU after i accidently broke one of the wires i soldered the joints to the PCB nicely and all seems to be well.
That was until i tried it on my multimeter... The speccy PSU is putting ... -
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 …
... not seem to be missing voltages I am afraid whatever killed ... -
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 -…
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 - it would just display the black square in the middle and not initialise itself to the ... -
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…
... buzz'. So I took some voltages around the 7805 regulator and ... should be.
The voltages around the lower RAM ICs ... -
Video fault on issue two ZX boardI've trawled the Internet and drawn a few blanks as to where to look to resolve the fault with my issue two board. I'm hoping a few of you knowledgea…
... />
I've checked the voltages are within specification coming from ... -
ZX81 internal RAM board?Just a quick question to Zorn (amongst others). What would the issues be with fitting one of Zorn's RAM boards into an unexpanded ZX81? Seems to me…
... generate and distribute the three voltages required by the 4116 chips ... -
Modern PSUHello everyone, I'm looking for a modern PSU for my Spectrums and my dual set of 3.5'' floppy drive+HxC floppy emulator. The one for Spectrum should …
... it to select between different voltages?
Also wouldn't ... -
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 …
... . However, the feed from the rectifier connecting to the 5v regulator ... -
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…
... , nothing goes into the LM1889. Voltages are correct, pin 3 (chroma ... -
Issue with Issue Two[img]https://dl.dropboxusercontent.com/u/25300140/Spectrum/Edited_ImageEasyImageEditor_20141111_84.jpg[/img] I'm working on an Issue Two that was sh…
... the picture above. The relevant voltages are -4.5, 4.9 ... -
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…
... getting power and all the voltages tested OK, so I thought ... -
I broke my 48k Speccy!!!!Hey guys, I am looking for some advice, I hope you can point me in the right direction. So, I went about replacing all the capacitors on my issue 4…
... . Totally corrupt.
The voltages on the lower ram are ... made no change to the voltages or display.
I ... now due to the weird voltages also.
Question.
voltages required for each cap? Or ... -
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…
... 's fine.
The voltages on the lower RAM are ... -
DivMMC Enjoy! Works on 3 of 4 48k Speccy's I own?Hey guys. I have a DivMMC Enjoy! Which is absolutely awesome! Love it to bits. It works perfect on three of my 48k Speccy's, but something isn't rig…
... is getting all the correct voltages/comms etc from the speccy ... -
ZX Spectrum+ video ? red on green problemThis is my first post on the forum, so let me introduce myself. I am retired for several years. For 30 years I have been a fan of the ZX Spectrum. I …
... /> I measured the power supply voltages at the relevant circuit points ... . All voltages are in line with service ... -
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…
... operation. All expected power supply voltages present.
- Confirmed CPU /M1 ... -
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…
... ?t=48605[/url]. Testing the voltages on the lower RAM IC ... /f6du3Ti.jpg[/url]
Voltages are still wrong on the ... -
Voltages from Original ZX Power suppliesHi. I've recently picked up a few power supplies in boot sales, one for a ZX81 and another for the ZX Spectrum. For the first time ever I decided …
Hi. I've recently picked up a few power supplies in boot sales, one for a ZX81 and another for the ZX Spectrum.
For the first time ever I decided to test the voltage on the jacks since I've just bought a multimeter.
The ZX81 ... -
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 …
... , so rebuilt the inverter. All voltages now OK. Still no colour ... -
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…
... new RAM, I checked the voltages, and the 5V and -5V ... -
Faulty Issue 1Hi all, thought I'd document my efforts in getting another speccy working. I've never done this before so please bear with me... I recently took a p…
... flashing paper area. Check all voltages are present as I've ... -
Issue 3B woesHello there, I currently have a Issue 3B for repairs around, it used to have broken upper and lower RAM, which I replaced with 41256-120 DRAMs (hac…
... " for a few minutes.
Voltages are at 5.1V & ... -
Testing 4116 type DRAMsHappy New year All! I'm managed to find some time to repair some more Spectrums :) woo hoo. I have a couple with busted lower RAM, Sooo, I appr…
... bread board with the correct voltages to the four pins whether ... .g. can I apply the voltages manually?
If not ... -
128 +2 grey, no video but still beepsGot a grey 128 from ebay, im using a 48k spectrum powers supply, all voltages seem ok. I cant get compostie video using the normal mod or from the 8…
... 48k spectrum powers supply, all voltages seem ok.
I cant ... -
Issue 3b boarddiode ID5 and cap C47 are missing from my board will these have any effect on system powering up. I have checked the voltages on the 7508 and its …
... />
I have checked the voltages on the 7508 and its ... -
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…
... back on and measured the voltages, 12v was giving me an ... -
Issue 4A, tests complete fine but get odd crashing problemHi all, I've got an issue 4A which has had all of its lower RAM replaced, TR4, TR5 as well as its CPU. It originally had quite high voltages (20-3…
... . It originally had quite high voltages (20-30v) on its 12v ... lot better. Figuring the high voltages wouldn't have been doing ... another set, no difference. The voltages on the RAM appears fine ... -
48K Issue 6a wobbly and flickering TV outputHi folks, Found an untested issue 6A Spec whilst tidying up and it had a warranty sticker on it from a past repair which seemed to be a socketed L…
... as usual I've checked voltages, TR1/TR2, the left-hand ... -
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…
... hooked it up and the voltages are off, 5v is fine ... -
Upper memory issueZX Spectrum 48K, issue 2, boots fine. Lower RAM OK. When tested with the new test ROM in the Diagboard, for all upper RAM tests "FAIL" is shown. I…
... the lower RAM, are the voltages:
4116 pin 8: [b ... don't see why the voltages could be related, the 4532 ...
