Ekco UL84 Voltage Issue

[Murphyv310]

Hi.
Moving the cap like you have done won't cause rasping noises. Check your work and make sure nothing is touching the speaker cone etc.

[Danndad]

The 1st pic shows it in its original position, 2nd pic shows where i moved it to.
The green wire goes to anode and the black wire to ht resistor r22, I tried it with no cap and its the same, I have now have taked the cap where it was originally and the radio is perfect.
I will put a new cap in tomorrow in the original position.
           

[Murphyv310]

Hi.
The pictures mean nothing a I don't know what tags the wires go to or from. Best idea is to draw on the circuit exactly what you have done.

[Danndad]

Not quite sure what you mean when you say the pictures mean nothing? I have explained what colour wires go where and you can see the cap connections clearly.

[Murphyv310]

I'd prefer seeing what you did on the diagram simply as putting the capacitor in parallel with the primary winding will not induce the effect you noted. I've done countless changes to this design anomaly on Ekco and other radios with no issues at all.

[Diabolical Artificer]

The cap shouldn't need replacing, it as far as I can tell acts (amongst other things) as a high pass filter together with the output transformers impedance to roll off high frequencies, IE parasitic oscillation, moving it might cause the radio to squeak. I'd leave it be. I might be wrong though.

Andy.

[Murphyv310]

Hi Andy.
I really don't see how a
0.01uf cap moved from the earthy side to the HT could make the radio squeak? Its a common mod to protect the output transformer primary. The vast majority of radios are done this way, occasionally with a series resistor.
I'm more dubious about relocating the G2 which I'd return to its original position then refit the cap in parallel with the O/P TX primary

[Danndad]

Here you are Trevor, I hope you can see where it is.

   

[Murphyv310]

Cheers.
Remove it from the top of the winding to the centre tap.
It goes from the bottom which is correct (anode) to the centre (reservoir cap) winding as this is a humbucking type of output transformer.
That should cure it and please return the G2 to the original position as per the diagram.

[Diabolical Artificer]

"I really don't see how a 0.01uf cap moved from the earthy side to the HT could make the radio squeak?" I agree Trevor, the cap's a snubber to stop back EMF but might also act as a HPF though at a quite high roll off so with a Class A SE OP stage it shouldn't effect anything. The only thing I can think of is the primary windings inductance and cap if connected wrongly (or right) might act as a tank circuit turning the OP valve into an oscillator.

Your advice of connecting everything back as was is sound. Andy.