04-08-2011, 09:51 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.
[attachment=2725]
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.
[attachment=2725]
If we've always had that, why is the car boot open? You aren't smuggling in another old TV are you...?
