01-17-2015, 11:00 PM
Today I was eventually able to bring myself to tackle another radio, having recuperated after the AK808A restoration - this one seriously sucked me dry of energy. Plus the closing and new house dolores de cabeza.
I chose Kirk's 62 of all the nasties that seem to creep up on me when I am not looking, like those weeping angels from "Doctor Who".
Now first I thought the power xfmr was a gonner until I realized this radio has a fuse that is also 110V/125V selector! And the fuse was open.
Now that it is bridged with a piece of wire the primary seems to be no longer open.
Which does not in itself mean the transformer is good.
The Variac-assisted test tomorrow will tell.
Meantime I am trying to make sense of the schematic.
There are two mods described in Riders, and mine seems to be the third.
I have the one where the field coil is plugged into the positive leg for filtering, but the sch in Riders shows another choke and 8uF cap which are not there, that filter plate voltage to the detector.
The first resistor to the bias filter seems to be huge wire-wound 9kOhm instead of 5kOhm shown, and I think it did not degrade as it is a wire-wound. It is a rheostat but the way it is mount I doubt it was moved.
The values shown are questionable: the two mershons on the chassis' drawing are shown to be 8uF and in the sch they are 2 and 4uF respectively.
And of course Kirk did not give me the speaker. Which has the field and the tranny. And I do not seem to have a speaker that could substitute for it.
So in fact I do not even know if the speaker is in working condition.
Oh...and the volume regulator is 18K end-to-end and all versions say 3K......minor thing, just minor......
That's my life for you.
OK. There we go.....
I chose Kirk's 62 of all the nasties that seem to creep up on me when I am not looking, like those weeping angels from "Doctor Who".
Now first I thought the power xfmr was a gonner until I realized this radio has a fuse that is also 110V/125V selector! And the fuse was open.
Now that it is bridged with a piece of wire the primary seems to be no longer open.
Which does not in itself mean the transformer is good.
The Variac-assisted test tomorrow will tell.
Meantime I am trying to make sense of the schematic.
There are two mods described in Riders, and mine seems to be the third.
I have the one where the field coil is plugged into the positive leg for filtering, but the sch in Riders shows another choke and 8uF cap which are not there, that filter plate voltage to the detector.
The first resistor to the bias filter seems to be huge wire-wound 9kOhm instead of 5kOhm shown, and I think it did not degrade as it is a wire-wound. It is a rheostat but the way it is mount I doubt it was moved.
The values shown are questionable: the two mershons on the chassis' drawing are shown to be 8uF and in the sch they are 2 and 4uF respectively.
And of course Kirk did not give me the speaker. Which has the field and the tranny. And I do not seem to have a speaker that could substitute for it.
So in fact I do not even know if the speaker is in working condition.
Oh...and the volume regulator is 18K end-to-end and all versions say 3K......minor thing, just minor......
That's my life for you.
OK. There we go.....
