Sinclair ZX80 / ZX81 / Z88 Forums

I manage to get the 12v to pin 11 but still no signal. I think the spectrum it's oficially dead.

Note, the +12V and -5V are also on the edge-connector. If you have a regulated 12V supply, you could always feed it in via either the edge-connector, or via D20 cathode connection. Of course, check, test and double check the polarity ;) You still need a nominal +9V on the power jack input for the 7...

TR9 has to be a fast switching power transistor. I'm not sure a BC548 will work (the BC548 and similar transistors are for audio frequency low power amplifier applications). Certainly a BC548 will not last long in the 16k and 48k models (although in these there is a higher load on the +12V supply)....

It's likely that TR8 (ZTX213) and TR9 (ZTX650, or ZTX651 or ZTX653) have been damaged. I suggest replacing TR9 first. If you test across C41 connections (or between D20 cathode (K) and 0V/GND) when the internal DC/DC circuit is working correctly, your meter should show about +12V even if the input ...

I'm just getting 6.5v on pin 11 mesuring from the power jack to the encoder.
I'm using a 9V power brick should I use a 12v one? If yes what is the far I can go with Amp's?

My ZX Spectrum +2 (Grey UK) was working but the connector of the PSU wasn't the correct size for the power jack. After picking um 2 PSU's I tried one and notice no power led or video. After that I cheked the PSU's and was one with the wrong poles for the Spectrum. I changed the voltage regulator and...

Hi people. My name is João, I'm 28 years old and I'm a proud (or was) owner of a Sinclair 128k ZX Spectrum +2 UK Grey version dated from 1986. My +2 was working fine but I change the PSU and i get the polarity inverted. I managed to get it working like power light drive and sound. But no video unfor...