Dead Amp

[Jamie89]

I was playing on my Orange Tiny Terror #4, switched it off and went for something to eat. When i came back to switch it on, I can't quite remember if it actually briefly came back on or not, its not working. Its completely dead. I have changed the fuse in the IEC lead which didn't do anything. I have taken the HT fuse out of the back of the amp but it looks completely intact. I have ordered some more though just in case. Are there any other obvious things it could be?

[Dmoney]

Do the valves light up but you get no sound?

I've never seen inside a #4 but I think in a normal TT they have an internal fuse. There is always a fuse built into the IEC socket on the back of the amp.

[Jamie89]

Doesn't light up at all. Is the HT fuse the one that is built into the IEC socket on the back of the amp? Its close in proximity to the IEC socket. I might have to have a look inside if the new HT fuse doesn't solve it.

[Dmoney]

The HT fuse is to the side of the IEC socket,

The IEC socket should have a little bit in the bottom that slides out containing a fuse. That is an additional mains fuse, I say additional because it's in line with your IEC cables fuse... This is good because a lot of peoples IEC cables have 13Amp fuses, would probably let the amp set on fire before they blew.

If nothing lights up at all, it could be a mains related issue. The filament circuit which lights the valves is separate the to the HT circuit. So if the HT fuse goes, it's entirely possible for the valves to still light up but make no sound. If nothing lights up, it sounds more like power isn't getting into the power transformer. But 'why' that has happened could be another issue entirely.

If it has an internal fuse like i can see on some normal TT photos, I'm not sure what the internal fuse does. It could be in the filament circuit and something could have happened to blow that too. I don't have a schematic for the amp. Obviously don't open it if you aren't comfortable, and the internal fuse (if it has one) probably has exposed metal parts which could be potentially be linked to high voltages. If thats to case, you don't want to touch it!

I don't have a schematic or a photo of the PCB, so if it has an internal fuse I can't tell you to take it out as I'm not sure it's safe.

[Jamie89]

Didn't realise it had another IEC fuse! Just taken it out, was a bar-steward to prise out, it doesn't look healthy at all! Looks like the culprit has been found. Thank you for the help, much appreciated.

[Dmoney]

No worries.

Obviously if you replace it and it blows again you have a serious issue and you need to get your amp looked at. Hopefully nothing too bad has happened.

[Jamie89]

Hopefully the fuse blew due to some less than serious reason. Its not due a service yet but if anything else arises I will take it in as I would have no idea what I am doing. I imagine the amp/me/both will end up worse for wear if I attempted anything...

[Jamie89]

The IEC fuse was to blame. The power comes on, but there is no sound! No hiss, nothing. Power tubes failed?
All the tubes seem to glow, not so sure about the tubes in the metal cylinders, there seems to be a faint glow from inside them

[Dmoney]

Reasonable guess it might be a power tube. If they failed and blew a fuse though and now you have no sound, you should probably get the amp looked at. The high voltages in the power valves can end up causing collateral damage if the tube failure is bad enough. I've seen LOADS of 5150's for example with only 3 working power tubes because one has broken and fried a resistor and then people just put 4 new tubes in but one socket won't be working. All the valves will light up, but that light doesn't mean they will be functioning at all unfortunately. 

[Jamie89]

Alright thanks. I shall take it to someone as soon as finances allow.