2015-03-29 - Several ZX Spectrum repairs

ZX Spectrum 48K with random colouring blocks
This ZX Spectrum also had some display distortion, so I started with replacing the 100 uF capacitors first.

The machine worked perfectly after that.

ZX Spectrum 48K with non-white border when booting
This was caused by replaced TR4 and TR5 with non-equivalent parts.

The 4116 RAM didn't power up quickly enough by this, causing the coloured borders.

After replacing TR4 with a ZTX650 and TR5 with a ZTX213, problem was solved.