Sony KV1320/1300UB - UK Vintage Radio Repair and Restoration Discussion Forum

Paul Godley · 23rd Apr 2017, 9:52 pm

I have just restored both a KV1300 and a 1320UB (thanks to members of this forum for parts help!)
On both these sets, the picture size /EHT regulation does not seem great.
At a reasonable Brightness/Contrast settings, the picture size increases and the raster crumples and the sides become bowed. at low settings the geometry is very good. I remember I has a 1320 many years ago with the same effect.

Is this normal for these early sets?
The picture quality otherwise is very good.
The KV1320UB is a Mk1 with the 3AT2 EHT rectifier and the Kv1300UB has a silicon rectifier. The results are the same on both sets. The emission of the 3AT2 seems good.
Just need to check before I go investigating a possible issue.

best regards

Paul

Welsh Anorak · 24th Apr 2017, 9:37 pm

I've had this when the CRT is getting a bit low emission and takes too much current, though it's pretty obvious from the poor picture you get if this is the case.
I'd hang a meter on the HT line to see if it's dropping.
Glyn

hans · 25th Apr 2017, 4:07 pm

Quote:

Originally Posted by Welsh Anorak

I've had this when the CRT is getting a bit low emission and takes too much current,

Wouldn't low emission lower the current?

Welsh Anorak · 27th Apr 2017, 2:13 pm

Good point, Hans, but you'd turn everything up to get a reasonable picture so that may well load the EHT. Possibly it might be a leak in the CRT rather than low emission.
Glyn

23rd Apr 2017, 9:52 pm	#1
Paul Godley Pentode Join Date: Jan 2014 Location: Doncaster, South Yorkshire, UK. Posts: 158	Sony KV1320/1300UB I have just restored both a KV1300 and a 1320UB (thanks to members of this forum for parts help!) On both these sets, the picture size /EHT regulation does not seem great. At a reasonable Brightness/Contrast settings, the picture size increases and the raster crumples and the sides become bowed. at low settings the geometry is very good. I remember I has a 1320 many years ago with the same effect. Is this normal for these early sets? The picture quality otherwise is very good. The KV1320UB is a Mk1 with the 3AT2 EHT rectifier and the Kv1300UB has a silicon rectifier. The results are the same on both sets. The emission of the 3AT2 seems good. Just need to check before I go investigating a possible issue. best regards Paul

24th Apr 2017, 9:37 pm	#2
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,918	Re: Sony KV1320/1300UB I've had this when the CRT is getting a bit low emission and takes too much current, though it's pretty obvious from the poor picture you get if this is the case. I'd hang a meter on the HT line to see if it's dropping. Glyn

27th Apr 2017, 2:13 pm	#4
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,918	Re: Sony KV1320/1300UB Good point, Hans, but you'd turn everything up to get a reasonable picture so that may well load the EHT. Possibly it might be a leak in the CRT rather than low emission. Glyn