break in period?

[radio nut]

I have read stories about how stereo amplifiers seem to have a change in sound quality after being run for a number of hours.
Is there a break in period for electronics?
My muntz television had an issue and I have not run it in a couple of months not too mention that it does not have much time on it since being repaired.

I fixed the issue yesterday and have left it running. All new caps and nos tubes. A LOT of resistors also changed.
It seems to need an adjustment here and there since. As an example Verticle size and linearity and contrast.
Is this Normal?

[marty59]

I've never really been comfortable with the term "break in", but I do believe components can and do change in live circuit applications, and maybe not always for the better. We've seen here many times when replacement parts will fail/drift out of spec, be tested out of value, or maybe an unchanged component after sitting idle for many years will now become unstable. It happens.

Components will "settle in" or stabilize so to speak.

Now you're at the point with your Muntz when it's time to "work the bugs out"!

[radio nut]

So far this set has been a pain.
The discriminator coil for the sound went out. The flyback burned up. The left side of the picture stayed fuzzy no matter what I did so I put in a new yoke and that cleared up that issue. I had to have Moyers make up the volume/contrast control since the volume control broke.
The original crt had slight burns on the screen so I put in a replacement 16rp4 and that went gassy after use quick.
So I have a lot of cash in a very low end set.
But the set has very good contrast and the sound is very nice since it (table top) was mounted on a home made base with a large speaker.

[Phil Nelson]

Maybe I lead a charmed life, but I've not had significant problems with new parts failing or changing value soon after installation. Much more often, an old marginal part will give up the ghost soon after it experiences full operating voltage and the heat of normal operation for the first time in decades.

In my experience, it's more of a "shake down" period than a break-in. That's why restorers give a TV a nice, long bench test after they think they're finished. It's not unusual for a few more little problems to surface during that phase.

Some of the things you mention sound like old parts that finally gave up. The discriminator coil and flyback might have been in bad shape when you got the TV. Breaking in had nothing to do with it -- they finally broke down. It sounds like the old yoke was bad and remained bad. No mystery there, either.

Just my $0.02.

Phil Nelson

[Eric H]

These things broke down frequently when they were relatively new, add in 50-60 years and the problem can only be worse. Muntz probably opted for the least expensive parts available to boot.
Caps are the worst but things like a Flyback that has to handle 10-25kv with decades old insulation, well it's a wonder they works as well as they do.

[VintagePC]

I'd agree with the "letting problems surface" shake-down. We still see it even with semiconductors today. Generally, if it's going to fail, it will do so within the first 24 hours of use.

Other than that I can't think of any sort of physical manifestation or effects related to a break-in period like you have for mechanical things (e.g. motor bearings or belt drives getting used to their particular quirks and wearing in to be "comfortable") except for maybe electrolytic capacitors "forming up" as they get used to their operating conditions, which may differ somewhat from the conditions under which they form the oxide layer in the factory.

Then again, electrolytics in bias circuits could very well alter sound slightly if they develop small amounts of leakage as they are worn in... someone more familiar with amplifier theory would be better able to comment on that, I think.

[radio nut]

Originally Posted by Phil Nelson

Maybe I lead a charmed life, but I've not had significant problems with new parts failing or changing value soon after installation. Much more often, an old marginal part will give up the ghost soon after it experiences full operating voltage and the heat of normal operation for the first time in decades.

In my experience, it's more of a "shake down" period than a break-in. That's why restorers give a TV a nice, long bench test after they think they're finished. It's not unusual for a few more little problems to surface during that phase.

Some of the things you mention sound like old parts that finally gave up. The discriminator coil and flyback might have been in bad shape when you got the TV. Breaking in had nothing to do with it -- they finally broke down. It sounds like the old yoke was bad and remained bad. No mystery there, either.

Just my $0.02.

Phil Nelson

I have done radios for years and not had this type of problem. I did not know to expect a settling in period. The more I run this set the less I have to adjust the height and contrast. Well now I know for next time not to be in a massive hurry to say its done and put it back in the cabinet.

[radio nut]

so, last question, when I turn this set on it comes up in horizontal lock fine. after that for about 30 seconds the picture gets wavy then goes back in lock and stays fine. should I try to adjust something or is this normal for vacuum tube technology?

[old_tv_nut]

Originally Posted by radio nut

so, last question, when I turn this set on it comes up in horizontal lock fine. after that for about 30 seconds the picture gets wavy then goes back in lock and stays fine. should I try to adjust something or is this normal for vacuum tube technology?

Might be normal for Muntz technology.

[Chip Chester]

The break-in period in audio gear mentioned isn't "infant mortality" or spec drift. It's stuff like a capacitor changing sound characteristics in apparently perceptible but possibly unmeasurable ways. And cables being directionally oriented to signal direction thru use or by design. Stuff like that. The audiokarma site (and many others) are rich in conversation on such matters.

Component value change due to heat does indeed happen, of course.

Chip

[Eric H]

Originally Posted by radio nut

so, last question, when I turn this set on it comes up in horizontal lock fine. after that for about 30 seconds the picture gets wavy then goes back in lock and stays fine. should I try to adjust something or is this normal for vacuum tube technology?

Without seeing a schematic I can't say for sure but there may be some adjustments for the horizontal besides the normal Hold control.
Many sets have either a frequency coil or a trimmer that can be adjusted for better stability.
It also could just be the Oscillator tube drifting a little as it warms up.