trio amp up in smoke-ya really up

[karma]

man it stinks when a old amp finally goes. good thing i have the camera next to me so i can take a shot. smoke sparks speakers are ok. but i think its time to retool.

i turned it off right after the fast shots. it fixable

[karma]

i took em so fast the last one had smoke but its out of focus o well

[karma]

total damage

2 12ax70 toast
4 7189a toast

[PeteMcK]

only managed to acheive it once many moons ago when I was kid,
when I didn't realise the TX I was using had a 110 v primary instead of 240v, the 80 rectifier valve had a permanent purple haze after that...at least I lived to tell the tale...
Pete McK

[karma]

i should have replaced the tubes when replaced the sockets
there super old original the geter was dark brown on some
i live close to the tube store so it will be a easy fix. from what i can see it was only one resister that is bad. we shall see

[ALBQ]

Karma,
I have a Kenwood KW-70 (Trio = Kenwood) receiver that almost suffered the same fate. Question, have you replaced any of the coupling caps tot he 7189s? When I first fired up my receiver, the plates of the 7189s would glow red hot in a matter of a couple minutes. Was caused by leaking coupling caps - bias voltage would drop to ~10V-12V. If this is the cause, is an easy fix
-ALBQ

[Sch3mat1c]

Yeouch! Had that happen to a 6L6GC (brand new Valve Art) once, it was within ratings... the oddest part was it still works to this day! Must've been a loose bit of screen wire that vaporized itself into working again...

Tim

[karma]

its weird how it all started. can u kill a tube by moving the amp when its powered up? the amp was on a speaker wire so i dragged
it over thats when the tube started shooting sparks in the filament.

anyway im looking at replacing em with this type

http://store.yahoo.com/thetubestore/russianel84m.html

heres a pic of the guts integrated->

[Frank Berry]

I looked at the first photo and saw a milky white color on the top of the tube that is glowing. That color indicates that the tube has lost it's vacuum seal.

Before your install new output tubes, make sure to check the d.c. bias supply (if the amplifier has fixed bias) and replace all coupling capacitors that have a d.c. potential across them.

[karma]

sure i will. the white is brown my camera is old. i allso found a

lot of bad wires that where coming apart and touching the case. it needs a lot of work

i started with the sockets just got to open the holes abit.
and ordered the tubes today