Pilot lamp falters.

[Sea Chief]

Hi chaps, brief question.

I noticed whilst playing last time, my twin reverb red pilot 'on' light falters/ dims momentarily, & did so fairly often.

Just kinda dims/ flickers every 20 secs, or so. No change in amp function whilst this happens.

I'm sort of presuming it can't be as simple as "change the bulb?" having never seen something similar ever in any other filament bulb.

Any ideas? Thanks, SC

[mikeydee77]

I find the bulb holders wear out over time and I guess heat... sometimes resoldering the bulb contact or polishing the contact helps... sometimes squeezing the bayonet fitting helps i suspect only temporarily though. I fairly often replace the bulb and fitting altogether.

I know you can led replacement bulbs but not tried them out yet.

Presumably tone impact would be limited LOL

[Sea Chief]

I find the bulb holders wear out over time and I guess heat... sometimes resoldering the bulb contact or polishing the contact helps... sometimes squeezing the bayonet fitting helps i suspect only temporarily though. I fairly often replace the bulb and fitting altogether.

I know you can led replacement bulbs but not them yet.

Presumably tone impact would be limited LOL

Hi Mikey, that seems a sensible avenue to persue.. I was dreading you/ someone might say " sounds typical of imminent PT winding X failing".

Relief. Thanks, will report back. SC

[SoulFetish]

Is it a reissue?

[Pedro Vecino]

This is the system I use to prevent the problem:

[SoulFetish]

I see this all the time with new production Fenders.
I don’t even bother using jumper wires. I tac solder the solder tab to the barrel where they meet, and another tac solder joint where the second tab meets the brass ring.
Just make sure not to use too much solder. you dont want to block the spring pin mechanism which holds in the lamp

[Sea Chief]

Is it a reissue?

Hi SF.

No it's actually a dead dog '78 UL135w.. reborn/ rebuilt with a new board (& as far as it could be with both original xfmrs), added choke & new filter board, to Blackface specs. By me.

This idea ( & the new rectifier config in particular taking a while) very kindly re-designed as we went along, by Rift Amps (who led me through final checks: so " signed off " I could call it by Rift, but it's -not- a product of theirs).


Thanks, SC

[Sea Chief]

I see this all the time with new production Fenders.
I don’t even bother using jumper wires. I tac solder the solder tab to the barrel where they meet, and another tac solder joint where the second tab meets the brass ring.
Just make sure not to use too much solder. you dont want to block the spring pin mechanism which holds in the lamp

I'm not totally on board with your idea SF.

What I have looks fairly different in general it seems:

[SoulFetish]

Its not different at all. Same type of lamp holder.
see where you soldered the wire to… folllow that piece of metal to where it meets another piece of metal. Solder those two pieces together.

But check your solder joints and check for shorts.

[Sea Chief]

Its not different at all. Same type of lamp holder.
see where you soldered the wire to… folllow that piece of metal to where it meets another piece of metal. Solder those two pieces together.

But check your solder joints and check for shorts.

Understood the same type of holder, just my additional resistors confused me.

So the principle being, there might be a bad contact between the main bigger barrel metal part ( ground presumably) & it's attatched solder tag... & a possible bad connection between the other solder tag, & the pin out the btm end ( + presumably) ? So adding a wire just in case, spanning these two respective points.

Where is the brass ring you refer to? I can't see anything brass.

Great help, thank you. SC

[Sea Chief]

I also find the base of my lamp holder touching the inside chassis. I can see it's not the positive terminal, but the outer 'C' shaped big metal thing.

SF I see you have an insulator something piece under here-?

Trouble is my chassis was crushed by courier, so had to bend back out the front angled facia. Did best I could but the lamp still isnt clear of the chassis as a result.

Thanks, SC

[Sea Chief]

Ok done the 2 small wire additions, (you may struggle to see lower one) a bit of board now under proceedings.

Will update later once amp fired up.

Thanks, SC

[Sea Chief]

SoulFetish actually this mod hasn't fixed it. I also have a huge hum introduced now too.

This amp is a never ending stream of ( noise ) problems I can't resolve so I can't sell it. And I need to sell asap.

[Sea Chief]

Chaps,

is there anything else that can cause this flickering pilot light?

Thanks, SC

[Delta362]

Did you try a new bulb? Sometimes the filaments in them break free and are just resting to make contact instead of being a solid contact. I've had similar bulb flickering and replacing the bulb solved it.