Marshall Class 5... no sound from it

[ermarshall]

Hi,
I own a Class 5. I like how it sounds, but some time ago it started to fail.
I was playing trough it and suddenly it started to make a crackling sound. I tough it was a preamp tube dying.
Some days later the sound started to die until finally it did.

I replaced tubes and have tried them into a orange tiny terror, but tubes work well. Someone told me to check all the resistors and I did with an ohmmeter.
the fuses and all inside appears to be good, I checked continuity in all the parts and everything appear to be ok, I dont know what else to check!

When I play full volume, I can hear the sound very far away.
Hope you can help me.

Thanks in advance. Blessings!

[dukealexan]

When mine failed, power tube went and it also blew the small fuse inside the amp

[zen]

...could be transformer on the way out...

[ClassicRock88]

There are fuses on the board. Sometimes if a power tube blows it will take one of those fuses with it.

[ermarshall]

Hi, Thanks for the answers.

I've checked the fuses and they aren't blown. Just a fuse, seems to have a slightly brown line in the center, but I checked with ohmmeter, and it has continuity.

Should I change the fuse even when it has continuity? I've never seen a blown fuse in my life, so I don't know if it has to be completely burned?

About the transformer, how can I test it is bad without buying another?

[skinnyj]

Hi, Thanks for the answers.

I've checked the fuses and they aren't blown. Just a fuse, seems to have a slightly brown line in the center, but I checked with ohmmeter, and it has continuity.

Should I change the fuse even when it has continuity? I've never seen a blown fuse in my life, so I don't know if it has to be completely burned?

About the transformer, how can I test it is bad without buying another?

As for the fuse, I'd say change it out. A fuse is a low cost item and it's good to have spares anyway.

[GuitarBuilder]

Take the fuse out of the circuit before checking it. Depending on where it is the meter may sense a complete circuit. Brown is not good!

[zen]

if your amp is dying slowly it's probably coil winding on transformer

[ermarshall]

if your amp is dying slowly it's probably coil winding on transformer

is there a way to test everything is ok with transformer?

[surfnorthwest]

if your amp is dying slowly it's probably coil winding on transformer

is there a way to test everything is ok with transformer?

Yes, but if you have to ask you probably should not be poking around inside of an amp for your own safety. Understand it is always difficult to troubleshoot an amp over a forum. While there are some obvious and easy things to check, once you have done that it really is time to have the amp serviced.

The Class5 is pretty simple and any repair should not be anything major at all with that amp. My advice at this point is to search out a good amp technician in your area and have it looked at.


I am going to assume your amp is out of warranty.