reduced capacitance, increased ESR, etc).Īs such, I always replace all the original electrolytic capacitors with high-quality modern equivalents, which usually improves the video quality noticeably.Īnother method of improving the video quality on the 48k (specifically, to reduce the “jailbar” effect on the background) is to increase the filter capacitance on the 12Vdc power rail, by installing 220nF ceramic capacitors in place of C5 – C8.Ĭircuit board stripped, and with new components installed.Ĭase Restoration (Including Keyboard Membrane)
#Monitor for a sinclair zx spectrum install#
As such, I always install a new DC power jack and new EAR / MIC 3.5mm mono connectors, and carefully clean both sides of the edge connector with a white eraser.Įlectrolytic capacitors are often used in electronics for decoupling and filtering, and are typically made from wound aluminium foil with a liquid electrolyte spacer – this electrolyte can dry out or leak over time, meaning that these kind of capacitors suffer from age-related effects which reduce their effectiveness (i.e. I/O ports and edge connectors on computers see a lot of use, and can corrode in storage.
Modern drop-in replacements for the 7805 are available, such as the Traco Power TSR-2450 – I removed the original regulator and heatsink, and installed one of these in its place. Linear regulators are inefficient, unreliable, and produce a lot of heat – this builds up inside the case, increasing the inside temperature and reducing the lifetime of the electronics. RF modulator interior following video modification.įrom the factory, the ZX Spectrum uses a 7805 linear regulator (attached to the large heatsink at the top of the board) to regulate the 9Vdc input voltage to 5Vdc. I removed it and cleaned everything up, then installed the modification more neatly and professionally inside the RF modulator, using a low-profile 100uF 10V electrolytic capacitor instead of a wire jumper – this blocks any DC offset on the video signal, improving display compatibility and reducing power consumption. The original video modification had been installed poorly, and in an irreversible fashion.
#Monitor for a sinclair zx spectrum mod#
The electronics seemed to be original with no signs of previous work, except for a DIY composite video modification – this is a common mod which makes the Spectrum output composite video over the RF jack, meaning the computer can be used with modern televisions and monitors. I buy most of my ZX Spectrum parts from Retroleum.
There are several steps which I like to take when performing a complete restoration on a ZX Spectrum, which include fixing factory or age-related problems, and future-proofing. The board was a 1984 ISSUE 3B, with 48k of factory-installed RAM. I bought the Spectrum as partially tested from a chap in Hull – it was in good, if a bit dirty, condition, and seemed to be all original aside from a DIY composite video modification. The ZX Spectrum in its original condition. This April, I’m raffling off a refurbished ZX Spectrum 48k bundle for charity – I recently bought a boxed Spectrum that would be ideal for this purpose, but obviously for this to be “refurbished”, it required refurbishing.
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