Marshall VS65R powers on ..No Sound

[DrGonz78]

You might want to consider the idea of building a home made signal tracing device since you don't have a scope. Very simple to just inject some sort of audio into the input of the amp and then trace the signal through the amp. If you have a cheap practice amp you can build something like this where you plug the tracer output plug into the little amp. In regards to the picture shown I would make sure the ground clip wire was longer too.


Here is something similar and with an actual picture. This one is from the billmaudio website. Do a search for more info on it too.

[Begbie]

Thanks DrGonz78
I will try that when I can find a suitable cap.
As this is my practice amp ill have to try another avenue to listen to the signal I'm inputting. Would love an excuse to buy a scope but I dont think i'd get enough use from it!

Where I'm at now is the 15v-+ rails are good again.
I get a really weak signal through the FX loop input but its not much louder than the one I get maxing the OD volume pot.
I bi-passed the reverb box and had no luck there so I'm figuring its somewhere between the 15v rails and the reverb which doesn't narrow it down much!

[m1989jmp]

Thanks DrGonz78
I will try that when I can find a suitable cap.
As this is my practice amp ill have to try another avenue to listen to the signal I'm inputting. Would love an excuse to buy a scope but I dont think i'd get enough use from it!

Where I'm at now is the 15v-+ rails are good again.
I get a really weak signal through the FX loop input but its not much louder than the one I get maxing the OD volume pot.
I bi-passed the reverb box and had no luck there so I'm figuring its somewhere between the 15v rails and the reverb which doesn't narrow it down much!

Excuse me if it's a dumb question, but are you *ABSOLUTELY* sure the ECC83 tube is 100% functional?

[g1]

I get a really weak signal through the FX loop input but its not much louder than the one I get maxing the OD volume pot.

On this model, when you plug your guitar into the FX return jack, you have to set the FX mix pot to full (10).

[Begbie]

On this model, when you plug your guitar into the FX return jack, you have to set the FX mix pot to full (10).

The "really weak signal" is with the fx loop pot on 10.

[Begbie]

Excuse me if it's a dumb question, but are you *ABSOLUTELY* sure the ECC83 tube is 100% functional?

Oh take it from me there is no such thing as a dumb question. I am beginning to believe that the solution to this problem is something that simple! That said though I have replaced the replacement valve so effectively I have three valve that I am swapping around when I'm testing. I figure they cant all be bad, but stranger thing have happened.

[The Dude]

Plugging a guitar into the effects loop will be weak. It expects a line level input and you are giving it an instrument level. It's just a test to see if the amp works. If you feel the need to verify the level, try plugging something in with a line level or variable level (like a CD player, mixer output, your phone, etc.) into that jack so you can give it a bit more juice.

[Begbie]

Ive been using the drum machine function on an FX pedal for the test signal. I will try with something else today!

Update: using an iPod I can vary the volume through the FX loop but even at max volume on iPod and amp its still really low.

[The Dude]

Have you tried a known good speaker or tested the speaker in the amp with something else? I know, ...... you can call me Mr. Obvious if you like. Just want to make sure before we go chasing all over the amp. A shifted speaker magnet would/could cause very low output.

[g1]

Also try headphones.
Do you still have T16 (muting fet) removed?

[Begbie]

Dude, the speaker works fine, but was something I hadn't considered thanks!

g1, Headphones produce the same weak signal, I put T16 back in after testing it originally but will remove it and try again. Thanks.

[Begbie]

Tested with T16 Back in and out no change!

[g1]

Have you built that tracer/probe yet?

[Begbie]

Have you built that tracer/probe yet?

No I haven't yet. Its my next step but work has been sapping my time hopefully I will get a chance in the next couple of days. Thanks!

[Begbie]

Ive built a tracer probe. It is working as it should (the probe the, not the amp).
I'm afraid I'm going to miss the fault though as I'm not sure sure where I am supposed to get a signal and where I shouldn't.