Help Marshall vs65r

[nickb]

No. The top of R9 looking at the schematic.

PS: Didn't you say you are in Sicily? I heard Mt Etna is erupting again. See anything?

[AL78]

Can you please tell me how to identify the top?on the board is the one connect to c5?

I live 20 minutes from etna Aci catena I live on the ground floor with building that obstruct my view,but from my bother house I see eruption in the night.Yesterday there were explosion and windows shook a lot...like when there are lighting but with the sun :-)

[nickb]

No, the other end that connects to V1. I realise that I've been saying V1 pin 3 but it could just as easily be V1 pin 7. V1 has two identical triodes and the pin numbers are not shown on the schematic.


I've never seen a volcano. It must be quite a spectacle.

[AL78]

So now that we identify the top of r9 with jack connected 0.500 mohm no jack 21.74 kohm to ground

Yeah but if you wanna see the lava you must go really really high.I saw once when I was a child.The opposite side is when It rains lava sand....

[nickb]

OK I now see that when you say "mohm" you mean Meg ohms. I was taking it as milli-ohm. Big difference. You are still on the wrong end of R9 but it doesn't matter. We now know the mute line is working correctly.

We have established there is a problem between V1 and IC5. Go back to the signal generator and ACV testing and measure the ACV on IC5 pin 2.

You may need a 10nF 400V ( 630V will be fine) capacitor to do more testing so best to figure out where you can find one now.

[AL78]

First sorry about the Mega ohm snafu LOL.About the capacitor are those the VAC type?

http://www.ebay.it/itm/10nF-630V-K-C...-/271440675234

[nickb]

AC or DC. That one on eBay is fine. Do the ACV measurement on IC5 pin 2 with the signal generator first.

[AL78]

Ok thanks I'll do it tomorrow Thank you

[AL78]

Hi I have a question about the cap(if I have to buy) are you talking about the c39 c 40 and c49 c 40?

[nickb]

It's just to allow us to make measurements in the high voltage areas.

[AL78]

So i'm giving 432mv i get 7mv

[nickb]

OK IC5 is OK, something is wrong around V1. The DCV around V1 are OK so I expect that V1 is OK too. You'll need to get that capacitor.

[AL78]

Is it possible that the tube is gone?How many caps i need?

[nickb]

It is possible, I suppose, but I'm discounting it as the DCV from earlier are OK. You need just one capacitor. I don't think we checked the ACV on V1 input- we should do that first. With the signal generator input, check the ACV on the junction of R9 and R10. Also check the junction of C5 and R9.

[AL78]

do you mean that i have to touch both sides of the r9?