Framus Ruby Riot 2 blowing mains fuse

[DrGonz78]

I guess that is with power tubes pulled?

Oh thank god!

[Emetal]

Could be a problem with the rectifier tube.
Pull the GZ34 and try again.

BTW, I just saw that the first filter cap is 220µ/350V. Way too large capacitance for a GZ34, especially with hot-(standby-)switching as used here.
GZ34 limit is 60µF. Also a 350V cap rating is too low. What a poor design!]

Yes, I pulled out only GZ34, all other tubes are in, and no problems, fuse does not blow up! So I should get the new GZ34 before doing anything else?

[Helmholtz]

Please answer post #15.

[Emetal]

Please answer post #15.

Honesty, those are voltages I wrote down on the paper schematic 6 months ago when this amp was with me last time, I do not remember under what conditions. But here are the plate voltages from this very moment, all preamp tubes and GZ34 are IN all power tubes taken OUT:
V1a=196v, V1b=254v, V2a=241, V2b=332v

[Helmholtz]

Yes, I pulled out only GZ34, all other tubes are in, and no problems, fuse does not blow up! So I should get the new GZ34 before doing anything else?

Yes, but I recommend to also replace C19 (220µ/350V) with 68µ/450V.

[Emetal]

Yes, but I recommend to also replace C19 (220µ/350V) with 68µ/450V.

OK I will (by the way C18 and C19 on the board are different then schematics, they are 220u/400V) And should I also upgrade that cathode resistor for power tubes R82, to cool them down as you suggested before? I can not find 68R/10w as wire wound version but have found cement version 68R/11w would that be OK?

[The Dude]

Yes, that is fine. A "cement" resistor is a wire wound resistor. 11W is fine, but 10W should be more readily available and cheaper. Surprised you can't find them. Here, for exmple:

https://www.digikey.com/en/products/...1068RJ/2365737

[Helmholtz]

And should I also upgrade that cathode resistor for power tubes R82, to cool them down as you suggested before?

Definitely.

[Emetal]

Yes, that is fine. A "cement" resistor is a wire wound resistor. 11W is fine, but 10W should be more readily available and cheaper. Surprised you can't find them. Here, for exmple:

https://www.digikey.com/en/products/...1068RJ/2365737

I'm in Serbia things are always weird here, I looked in few stores and that's what I'we found, will order from another country if possible, shore.

[The Dude]

Oh, like I said, 11W is fine if that's what you have available. My apologies for not considering the Serbia part of the equation.

[Emetal]

OK guys, rectifier tube GZ34 came in, installed, everything works, I could take the amp off the limiter bulb plug in normally and play. Well, then I did suggested improvements, changed C19 to 68uF/450v and R82 to 68R/11 watts and I think there is a problem, as soon as I turn on the Stand By switch, bulb limiter lights up and STAYS lit very bright! That's not good ha? Bulb should light up and then gradually go down right?

[Helmholtz]

I think there is a problem, as soon as I turn on the Stand By switch, bulb limiter lights up and STAYS lit very bright! That's not good ha? Bulb should light up and then gradually go down right?

What wattage is the light bulb?
I expect the amp to draw a lot of current, so a low wattage bulb will light up.

[Emetal]

What wattage is the light bulb?
I expect the amp to draw a lot of current, so a low wattage bulb will light up.

It's 100 Watt bulb. I don't think it stayed lit before like that in any case before, I mean I do not do lot of repairs but don't think it ever stayed lit much when everything is OK. If I take the amp of the bulb limiter what's the worst it can happen - fuse blowing up or something worse?

[Helmholtz]

!00W is not low wattage, so be careful.

[Emetal]

!00W is not low wattage, so be careful.

I know, so I am thinking of putting everything as it was, first the resistor since it's the easier part, then capacitor, but in between the changes I will try with bulb to see if I can catch witch change causes the bulb to light up and stay lit....