Valvestate 8040 Intermittent

[Cygnus X1]

Intermittent.

So I accept this job from a Cygnus amp owner, and it cuts out to no volume after warmup.
Changed THE TUBE.
No difference.

Banged it on the bench, now it doesn't cut out anymore.
Guess I'm screwed now!
Nothing worse than troubleshooting something that seems to work when it's supposed to.

While we're at it, same with My son's 760GLE Volvo.
Idle air controller works when it feels like it wants to.
Even after replacement.
But it doesn't work when it needs to...sometimes.

Herf....I'll be back.

[xtian]

I call these Singing Frog issues. Only sings for the owner, everyone else thinks he's nutso.

[Cygnus X1]

Looks like someone used that sticky type of industrial spray cleaner on it.
All of the pots are scratchy.

Methinks it's the common EFX loop issue.

If I'm lucky that gunk is reversible.

[Cygnus X1]

And my son gently twisted the contacts on his Volvo idle air control motor.
Seems to be fine again, for now.

[Reeltarded]

Tie a yellow ribbon round the old ok tree it's been three long years do ya still want me...

Weird things people say just before they freak out for $800, please.

[Richie]

Mostly look for cold solder joints, or bad or loose connections to the board from the pots. Also the speaker hookup. And clean any jacks. i think this amp has a preamp out, power amp in. Might also want to plug into those and check them,and clean the jacks.

HAHA.. the 8040 and 8080 are good amps to use for building a tube amp.
Find broken ones cheap, gut them and build a tube amp into the chassis.

1x12 combo, and nice large chassis to work with.. just throwing this in .

[HeeBGB]

I call these Singing Frog issues. Only sings for the owner, everyone else thinks he's nutso.

http://www.youtube.com/watch?v=NRnX4quv5W4

[Cygnus X1]

Mostly look for cold solder joints, or bad or loose connections to the board from the pots. Also the speaker hookup. And clean any jacks. i think this amp has a preamp out, power amp in. Might also want to plug into those and check them,and clean the jacks.

HAHA.. the 8040 and 8080 are good amps to use for building a tube amp.
Find broken ones cheap, gut them and build a tube amp into the chassis.

1x12 combo, and nice large chassis to work with.. just throwing this in .

HeeBGB, great stuff.
Chuck Jones is a hero of mine.



Miles...oh Miles...

Richie,
I thought you were going to help with the Volvo until you wrote "speaker".
That car has an exceptional sound system.

Owner might actually go for conversion.
He also has an 8080 that he bought "caught up in a fever, hotter than a pepper sprout".
I think he just wants it fixed to flip it.
Playing with the "Power Amp In" seems to be the culprit.

[Richie]

Hey, on the volvo, well not a volvo, but i had a Honda, the AC or Heater and vent controls. You can actually look this up on the web, to people that had the same similar problems.

No one knew what the heck it was that was causing it. I changed the relays in the box under the hood, which were a bit expensive. The most problem was spring or fall. If in the morning it was cool, and needed heat or defrost, it might work, it might not. And if it was working and then went off, it kept the heat open or on. Changing the control did nothing. Where ever it was when it went off, it stayed there!.

Same in summer. Needed AC. it might work or might not, or come on when it felt like it. It was a pain in the arse. I talked to all kinds of honda techs. Finally i went to a junk yard, and got another control. The part thats in the dash that everything hooks to. Once it was changed, it worked like brand new. Never a problem. I don't know if it was a manufacturing fault, but many people had the same thing happening. Could have been a chip on the board, to maybe a bad circuit board run. So maybe this might give you an idea on your volvo..lol

Oh yeah, when it had the problem, i could bang the dash, and it might come on, or if it was on and hit a bump it might go off. plus it might go off it it was cool, and then finally warmed up, it would go off.. After i changed the control panel for the heater /AC. I never had another problem.

[Cygnus X1]

One part of the challenge is the idle air system gets signal from the ECM.
ECM is not throwing any abnormal codes.
So if we chase that rabbit down the hole we are going to wind up getting a replacement ECM...which are reputed to be "not so good" compared to the originals.

Board repair could be in the works.

We have already reflowed the solder joints on the fuel pump relay.
It was obvious their process had left cold spots right at the junctions.

[Stratoblaster]

Intermittent.

So I accept this job from a Cygnus amp owner, and it cuts out to no volume after warmup.
Changed THE TUBE.
No difference.

Banged it on the bench, now it doesn't cut out anymore.
Guess I'm screwed now!
Nothing worse than troubleshooting something that seems to work when it's supposed to.

While we're at it, same with My son's 760GLE Volvo.
Idle air controller works when it feels like it wants to.
Even after replacement.
But it doesn't work when it needs to...sometimes.

Herf....I'll be back.

Cygnus, on the valvestate . Ive reluctantly been inside 2 before for friends. Same symptoms as you explain.
Both times the culprit was almost non existent solder joints on those big ceramic resistors to the board in the power amp stage. I found one had even fallen out & was rattling around loose inside the amp. Seems that they get very hot & cause that problem over a period of time.


Cheers,
Mark

[Cygnus X1]

Thank you Strat.
Right now it just seems to be the "Power Amp In" jack that causes it to cut out.

[Cygnus X1]

Problem solved.
It was the dirty jack.
Proper cleaning and it's good to go.

[Reeltarded]

This dirty jack is obviously an englishman..

Just pointing that out.

[Cygnus X1]

This dirty jack is obviously an englishman..

Just pointing that out.

Well I gave him a nice sponge bath but did not inquire about his existence.
I was feeling a bit out of my element (creepy, Wally) during the short time we shared the bench!