KB FB10 toaster

[Mark R]

Had another fiddle with this just, getting weak stations on MW but nothing on LW, there are no tunable signals with David's RF probe, so possible a coil somewhere.

Onwards and upwards, Yes Steve I changed the valve!

cheers Mark

[tiv48]

have you checked c13 ht decoupling and c9 agc decoupling
more likely to be wave change switch
rob t

[Mark R]

C 13 Has been changed Rob just on with the wave change

cheers Mark

[Mark R]

Further report on this blighter.

I found that on LW the set was not oscillating, attaching the scope to the connection of L4 showed this, yet it dis on MW. So C5 and C7 were changed. This got oscillation.

Now when you tune across to maximum capacitance on both bands oscillation stops half way over. HT on the anode of V1 was almost 250V. So now I m looking at R11 which should be 1.8k, and C9 which has to be changed. Looking at R10, that looks iffy too.

Both C16 and 17 have already been done.

By the way I am using Trader sheet 969.

further reports to follow.

Cheers Mark

[Mark R]

Oki doki, took R11, 1.8 K from the circuit and put it on the multimeter, the meter said "no", tried it on the Avo, no reading. So I changed it for a wire wound 1.8k.
Switched on tonight and stations all over MW and R4 on LW...............Brilliant!

R11 is the smoothing resistor, it seems this may be a stock fault on these sets. Set seems to be oscillating correctly with the correct HT and grid volts.

cheers Mark

[Steve_P]

Must have shot up in value. If there was something there when you scanned the dials then it can't have been fully O/C but high in value. Sometimes smoothing cap failure brings on a problem with this resistor!

I trust the one that has gone in is right for the current. Save you opening the set again.

Well done that man!

Cheers,

Steve P.

[Mark R]

Aye Sir Sydney a big 2W one. The smoothing and res caps had been done.
Forgot to mention I also changed C9 on the trader sheet the AGC decoupler.

not a scattergun in sight!

cheers Mark

[Mark R]

Here is the rascal in the cabinet which is free from damage

   

cheers Mark