Does anybody know the typical value for R160 in a BM3300?  It's the NTC thermistor in the power fail circuit.

The receiver has had new amp module and been re-capped but the power fail keep activating at startup

The voltage values around across the load resisitors R218 & R418 look good i.e. 0v which really only leaves the bias on TR33...

Thanks

Richard

I would personally look at the transistors associated with the protection circuit! You could disconnect one end of the ntc and see if that makes a difference. Have you checked all the transistors with a meter?

The Beomaster starts and runs fine with the thermistor R160 removed.  Its value at room temperature is only 52 ohms which I think is low and would explain the behaviour I am seeing when it is in circuit.  Does anybody know the correct type or which other models similar ones were fitted to?  I have looked through my Beomaster graveyard but have found nothing similar yet...

Richard

Ah ok sorry mate well looking at the circuit I would go for a 1k ntc.

Well its colours are Grey, Yellow, Orange which I suppose would indicate 84k if it's the same as normal resistors.  Google only has a little information.  I will try my local shop tomorrow...

Richard

You are far better going too low than too high! If emailing Martin (Dillon) doesn't come up with an answer and you want to find the highest resistance that will trigger the protection circuit (very important when choosing your NTC) then you could use a potenitometer in circuit turn from high to low and determine the cutoff resistance. Then choose a suitable ntc not from it's advertised value but it's 'resistance @ 80C' specs as an example.

BTW how did you get 84k???

It was a typo,  I meant 94k ohm (should have proof read my post) 

Now I look at in in another light it could be grey yellow orange which would be 84k ohm  

Ah grey (8)  orange(3) yellow(1x104) would be 830k but silver is a multiplyer only (and tolerance) so that would possibly indicate 0.43R which again is worse than what you have now.

84k seems way too high IMO.

Martin has just told me it is in fact 330k 10%. I have to go eat my socks now :)