KB FB10 "Toaster" radio.

[Geordie McBoyne]

I need something easy to fix, so how about this Kolster-Brandes FB10 radio?   As you can see in the second picture there is a slight damage on one side of the cabinet. That'll be an easy fix and after that job is done there is a aerosol of blue paint to finish it off.
Why blue? Because I already have red and white models in my collection.
I'll start off first with the electrical restoration. These sets are usually easy to fix.

The resto job on this little set will be light relief compared with the horror jobs I'm presently doing.
The list:    The Pye 405 line colour TV.   Pye TT1 transistor TV of 1961.   RGD 1046G radiogram.  Marconi RB12 smokers cabinet radio.   Any many more...  

Geordie McBoyne.

[Crackle]

There is not a lot to go wrong in those little KB sets, valves are nice and common.
Probably the first things to check are the output transformer, and the mains Auto transformer for the valve heaters, I have had faults on both on my radios.

Mike

[Crackle]

I forgot to mention, these little radios are the most common KB radio of all time, they were made with various modifications from 1950 to 1955. There are about 4 variations to the circuit for the FB10, and that is excluding the SW and FM versions. If you have any problems let me know, I should have one to suit.

Mike

[Geordie McBoyne]

Hi Mike,
apart from being a little bit down on sensitivity on Medium Waves the set is a goer.
There is only the damage to the side of the cabinet to sort out.

Never knew they made a version for Short Waves.

I'll remove the cabinet later today.

Geordie McBoyne.

[Geordie McBoyne]

Servicing the FB10.    As mentioned in a previous post about this set, it works in a fashion but the sensitivity on the Medium Waveband could be better.  After the cabinet was removed it was evident that this set is a late production model, the FB10/2   The output valve is a Brimar 6BW6 and the HT rectifier is a Brimar 6V4/EZ80. These valves replace the older octal 6V6GT and 6X5GT.
For starters I found that the 6BE6 frequency changer valve had been replaced by a EH90, you can get away with using this common pin compatible valve but the performance is not as good as the 6BE6/EK90.
Fitting a 6BE6 has improved the performance considerably and tweeking up the aerial and oscillator trimmers effected a further improvement.
Distortion on strong stations was caused by excess negative volts on the grid of the AF amplifier, a 6AT6.
The grid coupling capacitor C15 is leaky, replacing it improves matters considerable, but there is still overloading on strong signals.  The AVC decoupling capacitor, C9 is leaky. Now almost 5 volts of negative AVC is now available to reduce the gain on strong signals.
That taped up mains lead is definitely  not a good thing.  Sometime long ago the mains lead had been replaced with one with the brown and blue leads.  
So now there just the damaged cabinet to attend to.

Geordie McBoyne.

[Murphyv310]

Hi.
Nice easy job then!
I wonder how it'll look in Blue? Why not go for a nice metal flake finish and a stainless steel back cover, That'll soup it up a bit.

A plate of soup and some toast

[Geordie McBoyne]

Hi Trevor,
Metal flake finish? Perhaps the next FB10 that might come along. Seems there is plenty about.

Geordie McBoyne.

[Refugee]

You will need to defuse that tape bomb on the mains lead.

[Geordie McBoyne]

The mains lead has been connected directly to the switch. This set could do with a mains fuse for added safety.
Don't you just love those old style bodge jobs?

Geordie McBoyne.

[Geordie McBoyne]

An unfortunate choice of Araldite to repair the cabinet. I decided to used the quick curing stuff, the result after almost a week the Araldite was still not hard, in fact it was useless.
So today a second attempt with the ordinary slow curing Araldite. After twelve hours at room temperature the epoxy resin is already quite hard. I'll allow the Araldite more time to fully harden before any attempt to prepare the surface for sanding, priming and the application of the final blue finish.

Geordie McBoyne.