13-08-2012, 05:02 PM
(This post was last modified: 13-08-2012, 05:04 PM by Robert Darwent.)
(11-08-2012, 01:35 PM)Geaney Wrote: I can't imagine I'd find such baby tfo's locally though I might try the site you mentioned - for future reference.
Bardwell's isn't just a local shop, it is mail order as well and also has an eBay shop outlet. The transformer information I gave in the earlier thread is a link to their website if you click on it. I'm sure it won't be a problem to ship to you in Switzerland.
(11-08-2012, 01:35 PM)Geaney Wrote: I still have the voltage anomaly; where it says -7.8V at one end of R12 I have over -17V but at the pin of the 25L6 the grid 1 bias measures -7v versus the spec'd -7.5V so I'm not going to spend to much more time on that.
Thinking about your "voltage anomaly", I believe it isn't an anomaly at all. If you look at the part of the circuit diagram around R12, it is connected to the low voltage end of the heater/dial bulb chain.
You stated earlier that your set didn't have the correct 7V, 0.1A bulbs fitted. As a consequence the voltage drop they are intended to produce isn't as high as it should be and, together with other component tolerances, probably accounts for the extra 10V or so you are measuring at R12.
I don't believe it is an issue to worry about though, the bias circuit as a whole is obviously compensating, you are measuring near enough the correct voltage value at the 25L6 grid.
Regards
