KB FB10 Toaster - UK Vintage Radio Repair and Restoration Discussion Forum

nigelr2000 · 24th Jul 2021, 9:43 pm

I recently have been doing spillover repairs for a local classic radio shop as he is inundated with them. My main interest is Hi-Fi and the like from the 80's and 90's so this was a bit of fun for me.

It came with the fault card saying no LW and smoothing cap needs replacing.
In fact it needed all the waxies removing and replacing as well so once all this was done it worked.....sort of. After a quick re-alignment it performed very well but totally quiet on LW so I checked the LW coil on the ferrite rod as a finger produced interference, it was actually not connected the fine wires were missing from the coil. I removed the coil, found the ends and cleaned them up but still no continuity. A call to my friend about it and he only had the earlier loop aerial type for spares. I then spotted a Roberts R707 chassis and thought what have I got to loose, nabbed the LW coils and wired it in despite it being a centre tapped one and the wrong diameter for the rod. Imagine my surprise when radio 4 came blasting out. All it needed was sliding along the rod a bit to peak it and it was there, even the pointer was pretty close to the right frequency so a quick dab of glue gun to hold it in position and it was job done. Just goes to show that it's worth trying a wrong bit just in case.

Pics here ******************************CiMPgtCiGkErWLnUA

Robert Gribnau · 26th Jul 2021, 11:48 am

Nice job!

lightning · 26th Jul 2021, 10:45 pm

Good work, although the customer will probably never know the ingenuity that went into their repair.

FStephenMasek · 27th Jul 2021, 3:46 am

Is is indeed fun to get them working!

Isn't that cylindrical thing next to the band switch also a foil & paper capacitor?

nigelr2000 · 27th Jul 2021, 7:00 pm

Quote:

Originally Posted by FStephenMasek

Is is indeed fun to get them working!

Isn't that cylindrical thing next to the band switch also a foil & paper capacitor?

Nope ones a 2 watt resistor the the little one nearest the chassis front is also a resistor, had me worried for a moment thought I had missed one

See layout here http://www.kbmuseum.org.uk/kb_servic..._FB10-2_kb.pdf

telstar · 30th Jul 2021, 3:35 pm

One of those large 2 watt resistors had gone very high in value in my radio.
Cheers
Mike

Leon Crampin · 30th Jul 2021, 6:09 pm

A problem I had with my FB10 was broken valve socket forks due to brass dezincification. Several were missing one tine, giving rise to highly intermittent results and sometimes, no heater supply to the 6BE6.

Luckily they are easily replaced individually, but in any instances of intermittent operation of these sets, it's well worth gently probing the socket connections. In the "hints and tips" section, I suggested a means of improving the friction-prone tuning drive.

Leon.

nigelr2000 · 31st Jul 2021, 8:12 pm

Quote:

Originally Posted by Leon Crampin

A problem I had with my FB10 was broken valve socket forks due to brass dezincification. Several were missing one tine, giving rise to highly intermittent results and sometimes, no heater supply to the 6BE6.

Luckily they are easily replaced individually, but in any instances of intermittent operation of these sets, it's well worth gently probing the socket connections. In the "hints and tips" section, I suggested a means of improving the friction-prone tuning drive.

Leon.

I have had the same problem on record players with forked valve sockets, always keep a few sockets in stock just in case, I don't replace individual pins though it's possible as I figure the rest won't be far behind in failure

slidertogrid · 31st Jul 2021, 10:41 pm

Nice job and an ingenious solution!
I had valve holder problems with a PYE black box amp every one just crumbled or snapped when it was touched I suppose it is down to storage as other examples have been fine.
I have an FB10FM somewhere I really must dig it out !
Rich

24th Jul 2021, 9:43 pm	#1
nigelr2000 Heptode Join Date: Nov 2008 Location: North Walsham, Norfolk, UK. Posts: 900	KB FB10 Toaster I recently have been doing spillover repairs for a local classic radio shop as he is inundated with them. My main interest is Hi-Fi and the like from the 80's and 90's so this was a bit of fun for me. It came with the fault card saying no LW and smoothing cap needs replacing. In fact it needed all the waxies removing and replacing as well so once all this was done it worked.....sort of. After a quick re-alignment it performed very well but totally quiet on LW so I checked the LW coil on the ferrite rod as a finger produced interference, it was actually not connected the fine wires were missing from the coil. I removed the coil, found the ends and cleaned them up but still no continuity. A call to my friend about it and he only had the earlier loop aerial type for spares. I then spotted a Roberts R707 chassis and thought what have I got to loose, nabbed the LW coils and wired it in despite it being a centre tapped one and the wrong diameter for the rod. Imagine my surprise when radio 4 came blasting out. All it needed was sliding along the rod a bit to peak it and it was there, even the pointer was pretty close to the right frequency so a quick dab of glue gun to hold it in position and it was job done. Just goes to show that it's worth trying a wrong bit just in case. Pics here ******************************CiMPgtCiGkErWLnUA __________________ https://www.facebook.com/gntrading

26th Jul 2021, 11:48 am	#2
Robert Gribnau Heptode Join Date: May 2017 Location: Konongo, Ghana Posts: 513	Re: KB FB10 Toaster Nice job! __________________ Robert

26th Jul 2021, 10:45 pm	#3
lightning Heptode Join Date: Nov 2008 Location: Stockport, Cheshire, UK. Posts: 712	Re: KB FB10 Toaster Good work, although the customer will probably never know the ingenuity that went into their repair.

27th Jul 2021, 3:46 am	#4
FStephenMasek Pentode Join Date: Jul 2011 Location: Mission Viejo, California, USA Posts: 144	Re: KB FB10 Toaster Is is indeed fun to get them working! Isn't that cylindrical thing next to the band switch also a foil & paper capacitor?

30th Jul 2021, 3:35 pm	#6
telstar Octode Join Date: Dec 2003 Location: Leeds, West Yorkshire, UK. Posts: 1,592	Re: KB FB10 Toaster One of those large 2 watt resistors had gone very high in value in my radio. Cheers Mike

30th Jul 2021, 6:09 pm	#7
Leon Crampin Octode Join Date: Nov 2005 Location: Surrey, UK. Posts: 1,870	Re: KB FB10 Toaster A problem I had with my FB10 was broken valve socket forks due to brass dezincification. Several were missing one tine, giving rise to highly intermittent results and sometimes, no heater supply to the 6BE6. Luckily they are easily replaced individually, but in any instances of intermittent operation of these sets, it's well worth gently probing the socket connections. In the "hints and tips" section, I suggested a means of improving the friction-prone tuning drive. Leon.

31st Jul 2021, 10:41 pm	#9
slidertogrid Octode Join Date: Apr 2005 Location: Peterborough, Cambridgeshire, UK. Posts: 1,898	Re: KB FB10 Toaster Nice job and an ingenious solution! I had valve holder problems with a PYE black box amp every one just crumbled or snapped when it was touched I suppose it is down to storage as other examples have been fine. I have an FB10FM somewhere I really must dig it out ! Rich __________________ The rotation of the earth really makes my day...