KB Nocturne - UK Vintage Radio Repair and Restoration Discussion Forum

Steve_P · 4th Aug 2011, 10:48 pm

Sometimes, you have do something outrageous to get a set to work. The set pictured is a case in point.

It's an AC only set, with B7G valves. MW and LW, quite a nice little set that I paid for at the Wootton Bassett auction about a year ago. I had one as a kid you see. The valves are 6BE6 6BJ6 12AT6 EL90 EZ80. PCB built apart from the O/P valve, which is on a metal frame. Interesting design.

Anyway, got it home, laid it on it's front and took the back off. Somebody had been there first and after checking his work. I applied power and waited. It came up OK apart from the smoke from a wirewound resistor on the main board. This was burnt and so was the board around it, so I let it smoke for a while. That capacitor wanted changing but other than that, it was OK.

I was on my own here as I didn't seem to have a diagram for this set, and when this happens, the valve book is a bonus. I changed that capacitor and still the set smoked although it did sound a lot better.

This is where the outrageous repair comes in, and if you're of a nervous disposition, stop reading now.

I cut the old resistor away and sandpapered the board to get the burnt bits off. As this seemed to pass AC to the rectifier, it was carrying the entire unrectified HT and it was a very small wirewound. In my stocks was a great big 100 Ohms 100 Watts resistor, probably from a guitar amp and certainly too big to go where it's small predecessor had gone.

So it would have to go somewhere else. I found there was room for it at the side of the PCB so I got some wire and some glue (sorry) and fixed it in place where it wouldn't fall off or drop solder through the back onto a priceless carpet. Using proper solder and mechanical connections as well as the solder, I connected it up.

'Let's see you smoke now', I said to it. I often talk to radios – they are better conversationalists than people. And they don't take offence when I swear.

It didn't smoke, but amazingly the large resistor didn't get hot, but didn't stay cold either. Must have carried and still be carrying a lot of power.

Well, it's back in service now, and it's great when The Archers are on and there's no cricket blocking Radio 4 Long Wave....

Cheers,

Steve P.

JoshWard · 5th Aug 2011, 1:04 am

100 Watts?

Think that will last longer than the rest of the radio....!

Very pretty radio, well done

Josh.

mark pirate · 5th Aug 2011, 9:22 am

How about a picture of the guts Steve?

Mark

Vicboduk · 5th Aug 2011, 6:16 pm

My colleague has one of these and uses it for the cricket! It has an unusual construction in as much that it doesn't really have a case. Everything is mounted on the front board and a shaped fibre back enables it to stand upright. It looks as though it should be hung on a wall.
I'm fairly certain it shares the same PCB and circuit as the KB OB10 Minuet which in my view is a more practical and a better looking set - sorry Josh!

Vic

JoshWard · 5th Aug 2011, 8:55 pm

Quote:

Originally Posted by Vicboduk

I'm fairly certain it shares the same PCB and circuit as the KB OB10 Minuet which in my view is a more practical and a better looking set - sorry Josh!

Funny how you should say that as I have a QB20 Minuet on my to do pile (same case as the OB10 but with FM as well) and it's one of my favourite sets as far as aesthetics go.
Prettier than the Nocturne but the Nocturne does have 'something' about it which I like.

Josh.

4th Aug 2011, 10:48 pm	#1
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	KB Nocturne Sometimes, you have do something outrageous to get a set to work. The set pictured is a case in point. It's an AC only set, with B7G valves. MW and LW, quite a nice little set that I paid for at the Wootton Bassett auction about a year ago. I had one as a kid you see. The valves are 6BE6 6BJ6 12AT6 EL90 EZ80. PCB built apart from the O/P valve, which is on a metal frame. Interesting design. Anyway, got it home, laid it on it's front and took the back off. Somebody had been there first and after checking his work. I applied power and waited. It came up OK apart from the smoke from a wirewound resistor on the main board. This was burnt and so was the board around it, so I let it smoke for a while. That capacitor wanted changing but other than that, it was OK. I was on my own here as I didn't seem to have a diagram for this set, and when this happens, the valve book is a bonus. I changed that capacitor and still the set smoked although it did sound a lot better. This is where the outrageous repair comes in, and if you're of a nervous disposition, stop reading now. I cut the old resistor away and sandpapered the board to get the burnt bits off. As this seemed to pass AC to the rectifier, it was carrying the entire unrectified HT and it was a very small wirewound. In my stocks was a great big 100 Ohms 100 Watts resistor, probably from a guitar amp and certainly too big to go where it's small predecessor had gone. So it would have to go somewhere else. I found there was room for it at the side of the PCB so I got some wire and some glue (sorry) and fixed it in place where it wouldn't fall off or drop solder through the back onto a priceless carpet. Using proper solder and mechanical connections as well as the solder, I connected it up. 'Let's see you smoke now', I said to it. I often talk to radios – they are better conversationalists than people. And they don't take offence when I swear. It didn't smoke, but amazingly the large resistor didn't get hot, but didn't stay cold either. Must have carried and still be carrying a lot of power. Well, it's back in service now, and it's great when The Archers are on and there's no cricket blocking Radio 4 Long Wave.... Cheers, Steve P. Attached Thumbnails __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

5th Aug 2011, 1:04 am	#2
JoshWard Octode Join Date: Dec 2005 Location: Near Stowmarket, Suffolk, UK. Posts: 1,962	Re: KB Nocturne 100 Watts? Think that will last longer than the rest of the radio....! Very pretty radio, well done Josh.

5th Aug 2011, 9:22 am	#3
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: KB Nocturne How about a picture of the guts Steve? Mark

5th Aug 2011, 6:16 pm	#4
Vicboduk Hexode Join Date: Aug 2007 Location: S.W. London, UK. Posts: 416	Re: KB Nocturne My colleague has one of these and uses it for the cricket! It has an unusual construction in as much that it doesn't really have a case. Everything is mounted on the front board and a shaped fibre back enables it to stand upright. It looks as though it should be hung on a wall. I'm fairly certain it shares the same PCB and circuit as the KB OB10 Minuet which in my view is a more practical and a better looking set - sorry Josh! Vic Last edited by Vicboduk; 5th Aug 2011 at 6:27 pm.