Ferguson 461

[alanworland]

Measured the speaker field coil at 1500 ohm and found it had 85v across it, giving 56mA. I don't know if that's good or not?
I measured the output transformer primary at 500 ohm although Trader sheet doesn't give a figure for this (it had 21v across it)
The smoothing caps C28 and C29 had 207v and 305v respectively across them. Once again Trader sheet doesn't give a figure but the 305v I found would suggest there is sufficient? I also measured 6v ( AC) heater supply.
Set seems to have a fair amount of volume available just. noisy and mushy?

Alan

[David G4EBT]

Originally Posted by alanworland

I measured the output transformer primary at 500 ohm although Trader sheet doesn't give a figure for this (it had 21v across it)

Trader Sheet 800 (for the AC version) gives the value of all the inductors/transformers, and states:

Field coil 1500R
Speech coil 1R5
Hum bucking coil 0.25R

Output transformer primary: 470R (Your 500R is only +6% so no worries there).
OPT secondary 0.3R

Hope that helps a bit.

[alanworland]

Thanks David, I don't think there can be a great deal wrong with it (although I have found a couple of resistors high)
I will be back on it shortly - and try and remember where I left off.

Alan

[PJL]

The current seems about right so I would guess the AZ31 is a bit low. I would avoid fiddling with the mains voltage selection as this would overrun the heaters.