Crate VC5310 power tube failure ,and fuse blown.

[Enzo]

Larger things like caps and the 10 watt resistors tend to vibrate and crack their solder over time, so they goop them to prevent that.

A little freeze spray on the hot melt and you can shatter it with a screwdriver. Easy off.

[Pedro Vecino]

OK, Enzo. Thank you very much for the explanation. I've gone crazy looking for the R43 resistor.
The models I've seen have always been fixed bias, with no room for adjustment. I have always used a bias circuit Vox AC50 style (for HT secondary without center tap) coated with heat shrink tube.



It can be mounted externally without extracting the PCB carrying the negative line to the junction of the two resistors of 220K previously disconnected.

[Enzo]

Of course other alternatives exist. Just as initially we suggested a voltage doubler be made in place of the straight rectifier of stock. But when looking at the board and remembering the place for a resistor was already there, it seemed a natural to stick one in for a bias boost. If you think a small outboard circuit would be easier or better than the resistor, no argument from me.


I guess if you drop in at the end, "R43" can be mysterious. I did explain where it was on the board and why it was there when I introduced it.

[Pedro Vecino]

Yes, I knew that there was a place for a big cathode resistor (R43) and an a electrolytic. Once I turned the amp to cathode bias to test it but with these resistor value bias are very hot. I imagine that 75/82 Ohms is a more appropriate value.
I think I have some kind of problem with my computer and see that there are 107 responses but appear only two pages (I can not read many messages).
The system of adding a low value resistor to the cathodes is more simple and practical.

[Enzo]

used alone, I'd pick 100 ohms or even higher.



As to not seeing the entire thread, are you viewing in linear mode? That is one of the preferences in your user profile.

[Pedro Vecino]

OK. I didnīt know the existence of such function. Now I see the whole topic. Thanks again!

[gtrplayr1976]

I plan on firing it up again this evening to see how it sounds . I'll report back after that.

[gtrplayr1976]

I put the VC5310 to work last night. It all seems ok at this point. I hear no issues. I installed the 10 ohm 10 watt resistor at R43 ,and left the rest stock. If an issues does crop up I will return Thank you for all the help.