'evil' twin with no sound or pilot light

[shirbomi]

my 6 year old fender 'evil' twin has stopped making any noise. I have replaced the tubes (thanks for the advice/help) and checked all the fuses and I am now out of ideas!

The trouble lights are okay / green at the back of the amp but the pilot light is not on. Has anyone had this before - can you offer any advice as to what it is and what i need to do please? many thanks
MS

[EETStudent]

Is there ANY noise coming from the amp, such as hum or noise of some sort? Even faintly?

Well, a pilot light(power switch indicator)that is wired correctly and does not come on generally indicates a failure in the power cord or the power transformer. In a case where the power cord isnt accepting the 120vac wall voltage and triggering the primary of the transfromer, the 6.3vac windings from the secondary(assuming your pilot lamp runs off the 6.3v winding) would not be functioning and the light would not get the supply. That also means the tube heaters would not get their supply either, so if your tubes arent even lighting up then you probably have a problem with the power transformer.

[52 Bill]

If the trouble lights on the back light up, then the amp is getting some power. Do the tube heaters light up? If you don't know this, the heaters or filaments appear as small glowing orange lights in the center section of the tubes. If they do light up, then the power transformer filament circuit is probably ok and your pilot lamp is either burned out or not making good contact in the socket. Try unscrewing the red jewel from the front of the amp and then wiggle the bulb in the socket. If it still doesn't light up, remove the bulb and inspect the tiny filament inside the glass.

Try plugging your guitar cable into the FX return socket and/or the power amp in socket. Can you hear the guitar signal now? If you can then try cleaning the jacks with a little spray contact cleaner.

If you turn up the reverb control and shake the amp a little can you hear the reverb springs crashing?

Let us know what you find out.

[Enzo]

Without looking it up, isn't the pilot light on this one an LED behind the jewel? In which case looking for cracked solder comes to mind for it.

[shirbomi]

thanks for the quick response guys, the pilot bulb looked fine with no obvious damage to filament etc. The tubes are not lighting up - which from what you have said means there is a power transformer filament circuit problem, which makes the pilot light a 'by-product' of the bigger issue.

I will have a look tonight at the power section with an electrician friend of mine and also try the FX loop tip.
thanks for the help. MS

[Steve Conner]

London, England, or London, Ontario?

I ask because I heard the Canadian electrical code requires guitar amps sold in Canada to have fuses in their filament circuit. One of these could have blown or come loose in its holder. They're probably inside the chassis and not accessible by the user.

[shirbomi]

London England - & good canadian electrical knowledge!

[52 Bill]

Good Call Steve!
According to the schematic, the UK version of this amp has a fuse in the filament circuit as well, check that first. Fuse 201.

Just as a side note, this is the modern Twin with the red/green trouble led on the back panel. I normally hear the "evil" word associated with the 1980's red knob version. Is there a new "evil" Twin now?

[shirbomi]

yes - looking like a very good call indeed. I've been a bit brave and taken it apart and discovered (within a black plastic housing) a very dubious looking fuse .... I'm off to check it now.

Yes its the fender twin with separate gain channel, 'trouble' LEDs on the back and no red knobs. I've heard it called the evil twin because of the gain channel - I may be wrong - it has happened!

http://www.fender.com/products//sear...tno=0215700000

[Amp Kat]

I don't know which one they are referring to but the 94 reissue is as evil as they come. They have some ground issues and the low voltage circuit dissipates to much heat and burns crap up. Those are the ones I call evil twins.

[shirbomi]

thanks steve and everyone else for all your help. ?2.39 in Maplin later and i have a fully working amp again - it was the fuse to the power transformer inside. Is there anything nicer than seeing tubes glow in an amp again? Deep joy. Thanks so much for your help
MS