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Back | Last edited: 2007-09-23 kio |
All connectors of the ZX Spectrum are at the rear side of the body.
This is the connection for the power supply unit. This is no longer a 3.5 mm mono jack as for the ZX80/81, but a 5.5 mm holow plug with 2.5 mm inner diameter, so it can no longer be confound with the audio jacks. But still the unit has to be reset by unplugging the power cord.
The PSU delivers unregulated, nominal 9 Volts DC. The tension without load is about 15 Volts. Center pin is Gnd, shaft is +9V.
The expansion bus offers a direct connection to many Z80 CPU signals. It is intended to connect the Sinclair ZX printer and other peripherals to the ZX Spectrum. It has been widened by 2 x 5 pins compared to the ZX80/81 expansion bus and some signals have been relocated. All Sinclair ZX Spectrums up to the grey +2 and most clones used the same expansion port. The following chart shows the connector layout of the expansion port.
Expansion port connector layout of the ZX Spectrum
| Uss | is the +9V from the power connector. |
| –12V | is the widely drifting voltage from the switching regulator (chirping coil). |
| FBAS | this is the complete colour video signal. |
| /Y | is the BAS signal, the inverted b&w signal including sync. |
| U and V | are the colour difference signals including PAL coding. |
| IOULA | is the ULA address select signal for the incompletely decoded i/o port 0xFE. |
It should be noted that the upper (component) side is referred to as side A on the issue 1 and issue 2 PCB and docs, but as side B since issue 3. This lead to some errors and ambiguities in subsequent documentation. The best is to double check each time which side – upper or lower – is actually meant by side A or B.
This is the audio output for saving programmes and data to a tape recorder. It is a 3.5 mm mono jack. It can be connected to the Mic or Line in input of the tape recorder or HiFi equipment.
This is the audio input for loading programmes from a tape recorder. This is a 3.5 mm mono jack too. It can be connected to the Ear or Line out output of the tape recorder or HiFi equipment.
This is a Cinch socket which should be connected with the supplied cord to the TV antenna input. The signal of the ZX Spectrum should be on UHF channel 36.
Page source: The Sinclair ZX Computers Archive <k1.spdns.de>
copyright & courtesy of kio@little-bat.de
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