-
Spectrum 48k PSU voltageI have been running into problems with my rubber key speccy. To cut a long story short I did a voltage check of my power supply. It seems to fluctuat…
... it will do to the DC-DC converter section.
Someone in ... -
2 48K speccys dead..Hey guys! I've got two of our rubbery friends with me that need some help. They've been like this for some time, but I would like to try and fix th…
... on-board voltage conversion circuitry (TR4/TR5 IIRC), but if caused by ... -
2 48K speccys dead..Hey guys! I've got two of our rubbery friends with me that need some help. They've been like this for some time, but I would like to try and fix th…
... on-board voltage conversion circuitry (TR4/TR5 IIRC), but if caused by ... -
2 48K speccys dead..Hey guys! I've got two of our rubbery friends with me that need some help. They've been like this for some time, but I would like to try and fix th…
... if I can replace the TR4/TR5 transistors tomorrow, and hope there ... -
2 48K speccys dead..Hey guys! I've got two of our rubbery friends with me that need some help. They've been like this for some time, but I would like to try and fix th…
... to get new capacitors ASAP, TR4/TR5 are out of question 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…
... supply circuitry and fit a DC-DC chip with a 5v output ... , However, you can replace the DC-DC converter section with a dedicated 5v ... -
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…
... , However, you can replace the DC-DC converter section with a dedicated 5v ... is to re-route the DC input voltage (from battery in ... the video circuitry. Then with DC-DC converter in place of the 7805 ... -
Spectrum not working, can anyone help this lady?[URL="http://www.retrogamer.net/forum/viewtopic.php?f=6&t=29734#p674152"]http://www.retrogamer.net/forum/viewtopic.php?f=6&t=29734#p674152[/URL]
OK. Then I can assume that the DC-DC converter is working. If every time you turn it on, the border is white, I'd say you likely have a damaged chip from the RAM at low bank. Less likely a problem with the multiplexers or the RAM at high bank. -
Spectrum not working, can anyone help this lady?[URL="http://www.retrogamer.net/forum/viewtopic.php?f=6&t=29734#p674152"]http://www.retrogamer.net/forum/viewtopic.php?f=6&t=29734#p674152[/URL]
... I can assume that the DC-DC converter is working. If every time ... -
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.…
... a heatsink-less high efficiency DC-DC converter IC like the ones I ... -
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 …
... regulator and use a modern DC-DC converter.
The ones I ... -
Merging romsHello, I want to flash an eprom with two roms so I can make a speccy be able to have a dual rom using an external switch. I thought i had it right b…
... be fine.
- The DC to DC converter. In my board it's ... -
Merging romsHello, I want to flash an eprom with two roms so I can make a speccy be able to have a dual rom using an external switch. I thought i had it right b…
If you read EZO forum, there are a lot of issues with incorrect voltages on Willem. My Willem has only 12V power supply, but DC-DC converter, yes it could be source of problems. Maybe one day I will give it a look again. -
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…
Never had worn out tr4 tr5. I had either working ones or dead ones.
I have come across worn out (but still working) 7805 voltage regulators causing wavy screen or even colors dissapearing. -
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…
... all the elctrolytic capacitors and TR4/TR5 chips as well as all ... -
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…
... if I order a replacement TR4, TR5 & C46 I should be ... -
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…
... if I order a replacement TR4, TR5 & C46 I should be ... -
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 suggested ... -
128k Toastrack repair advice needed..Hey all, Just got my second toast rack in a oddball deal when i visited a local farmer for some other second hand stuff. The 128 was sitting in a p…
... know where to go next.. tr4/tr5 check out ok, so something ... -
ZX Spectrum TowerHi all, i am working on a ZX Spectrum 48K build in a PC tower case. Is there anyone who did it before? I have some questions duo the PSU. I have to g…
... the voltage regulator with a DC/DC converter. I believe the 7805 is ... -
ZX Spectrum TowerHi all, i am working on a ZX Spectrum 48K build in a PC tower case. Is there anyone who did it before? I have some questions duo the PSU. I have to g…
I would use a DC-DC converter, much more effiecient than a linear regulator. -
Help changing TR4 and TR5Hi all! Please, help me! :) I think I'm not understanding the correct pins of TR4/TR5 and the transistors. So, if anyone know the correct pins, help …
... and BC307 to use in TR4/TR5.
And I found some ... original pins that?
TR4 TR5 TR4 TR5
E C |\ /|
For TR5 I use BC557 instead BC307 ... -
48k PSU UpgradeCan anyone give the definitive word on a PSU upgrade (rather than just a replacement) for 48k machines? I'm thinking of adding at least an IDE inter…
... with a molex connector, a DC-DC converter (similar to 7805) but which ... -
48k PSU UpgradeCan anyone give the definitive word on a PSU upgrade (rather than just a replacement) for 48k machines? I'm thinking of adding at least an IDE inter…
... more modern and cooler running DC-DC converter is a good idea.
48k PSU UpgradeCan anyone give the definitive word on a PSU upgrade (rather than just a replacement) for 48k machines? I'm thinking of adding at least an IDE inter…
Yes, using a better DC-DC converter would be a good idea. ... to distribute that between separate DC-DC converters to lower the load ...48k PSU UpgradeCan anyone give the definitive word on a PSU upgrade (rather than just a replacement) for 48k machines? I'm thinking of adding at least an IDE inter…
... the RECOM R-785.0 dc-dc converter I received today in my ...48k PSU UpgradeCan anyone give the definitive word on a PSU upgrade (rather than just a replacement) for 48k machines? I'm thinking of adding at least an IDE inter…
... pointed me towards a better DC-DC converter to use for my spectrums ... speccies. At least until these DC-DC converters need replacement (if ever ...48k PSU UpgradeCan anyone give the definitive word on a PSU upgrade (rather than just a replacement) for 48k machines? I'm thinking of adding at least an IDE inter…
... pointed me towards a better DC-DC converter to use for my ... speccies. At least until these DC-DC converters need replacement (if ... http://www.tracopower.com/products/dc-dc-converters/pol-point-of- ... /"]www.tracopower.com/products/dc-dc-converters/pol-point-of- ...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 …
... -transformer is part of a DC-DC converter circuit that generates the 12V ... would be a traditional switching DC-DC converter. I.e. some version of ...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…
... slightly different design for the DC-DC converter. However, the PCB layouts are ...
