Quote:
Originally Posted by David G4EBT
As to 'not getting anywhere with the Nostalgair tests and your signal tracer', in fact you were, because the tests showed that the oscillator wasn't working, just as if - for example - you put an Ohmmeter across a fuse and 'get no reading', it proves that the fuse has blown.
|
Apologies David, poor wording on my part as the tests did indeed show that the oscillator wasn't working - a crucial step in finding where the actual problem lay i.e. a poor solder joint on the underside of V2.
Nostalgia Air: Signal Tracing is a very good resource so thanks again for the link.
Quote:
Originally Posted by crackle
I am assuming you changed C39 (trader).
|
I know it's been a long Thread but way back in Post #2 I mentioned: -
"Next Step is to replace both C38 and C39 – A.F. coupling capacitors - before our first live test, with the lamp limiter of course.
The Service Sheet shows C39 as 0.02μF although what has been fitted in my set is 0.001μF. On the assumption that Kolster-Brandes made this change for good reasons (?) I'm going to replace like for like ..."
Both C38, C39 (Trader) and a number of Hunts Mouldseals and waxy paper capacitors have all been replaced - like for like.
I note what you write about removing, dismantling and cleaning the Tone control - something I have been avoiding but now know I have no real choice.
I have looked around for an appropriate 250k with double pole switch but can't seem to find an exact match, specifically in relation to the d-shaped metal spindle.
The KB Museum Service Data sheet lists this as: -
Component: Potentiometer 1/4 M.ohm and D.P.S.
Part No. : 80670 / 5
Price : 8/-
I make that 40 New Pence as we used to say back in 1971!