UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Oh no

Steve_P · 12th May 2010, 3:34 pm

If the power supply is down then everything will be down. It's fairly simple on these, two PY82's in parallel and a few resistors to check. Make sure the PY82's are OK and if not, change them both.

Then get the horizontal hold within range. There are a few 0.1 caps here and an electrolytic, 12uF. Also R121 and R122. There's a trimmer cap too marked 'pre-set horizontal hold' that may need a tweak.

Put the Horizontal Hold in the middle, tweak the capacitor and pull it in. And use a scope for checking frequencies. Not your ears. If it's off, then the line output stage will not work properly.

Cheers,

Steve P.

12th May 2010, 3:34 pm	#35
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Oh no - another V4! If the power supply is down then everything will be down. It's fairly simple on these, two PY82's in parallel and a few resistors to check. Make sure the PY82's are OK and if not, change them both. Then get the horizontal hold within range. There are a few 0.1 caps here and an electrolytic, 12uF. Also R121 and R122. There's a trimmer cap too marked 'pre-set horizontal hold' that may need a tweak. Put the Horizontal Hold in the middle, tweak the capacitor and pull it in. And use a scope for checking frequencies. Not your ears. If it's off, then the line output stage will not work properly. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?