ZX Spectrum +2 (grey case) modifications

After many years of using +2 I made several modifications of my +2 to refine some let's say "bugs" which brings me to mad. Now I collected them here and I highly recommending all of them.

Distorted picture on RF and video out
Due to production mistake and poor video circuitry design, picture on +2 isn't so good as it could be. First "bug" is C31 which is intended to mix sound with picture, but it brings lot of noise to picture. I decided to remove it, because I use stereo audio out. So if you want better picture on RF, and you don't bother about sound on RF, remove C31. Keep in mind that earlier boards had this capacitor underside between legs of IC2.
Video out (CVBS) is normally also unusable on some boards, because TR4 is turned to wrong position (because of silkscreen error). If you have dark distorted B/W picture on CVBS, this might be the cause of it. Simply pull TR4 out, turn it by 180 degrees (the opposite to silkscreen) and put it back. If you removed C31 also, you will be surprised by picture quality on CVBS.

SS+A, and some other keys not working when computer is cold
This is caused by overloaded addres lines. Put 82pF or 100pF ceramic capacitor over diode D35 (on some machines also over D33) and problem will disappear.

ULA snow effect (raining)
Another hardware bug. It appears when I is set to slow RAM. It can be resolved by replacing original PAL10H8 chip by new reprogrammed GAL16V8, which includes /RFSH in its equations. We call it UMBRELLA and big thanks goes to Poke, who analysed old PAL10H8 and made new equations for GAL. If you want to get rid of snowing/raining simply remove PAL10H8 chip, put UMBRELLA GAL16V8 instead of it and connect /RFSH to its pin 11. No other modification is needed.

ACB stereo output (with beep mixed in)
There is mono audio out only by default, poor quality, lot of noise. I built stereo audio output, where is ACB stereo from AY and also beep mixed, so I can fully enjoy Chase HQ music ;-) ACB mixer is here, beep is connected directly to L and R outputs of ACB mixer, through simple transistor amplifier, diode (for small voltage drop) and two 1k resistors.

Pictures:

C31 removed	TR4 position	Capacitor over D35	UMBRELLA GAL
ACB+beep ugly hack