Admiral 14R12 Restoration

[Captain Video]

You have done an AMAZING job on restoring this set!!!! My most sincere congratulations!!!

[Polaraligned]

Curious still, why did you feel the need to replace all the resistors and mica's? Most restorers only replace the electrolytics, paper caps and then resistors that measure out of tolerance.

[Crist Rigott]

Originally Posted by Captain Video

You have done an AMAZING job on restoring this set!!!! My most sincere congratulations!!!

Thank you.

[Crist Rigott]

Originally Posted by Polaraligned

Curious still, why did you feel the need to replace all the resistors and mica's? Most restorers only replace the electrolytics, paper caps and then resistors that measure out of tolerance.

Because you have to replace all the electrolytics and paper caps, there were like maybe 6 micas left. They have been known to got bad. So why not replace them too? There cost isn't too much either. Also it eliminates problems down the road. Say a mica still works, but then several hours it decides to quit. Then you have to go back and pull the chassis, trouble shoot the problem, replace the mica, maybe do another alignment, then put it back together. Seems the risks and rewards aren't worth NOT replacing the micas. Also when replacing the paper caps, most of the time there is a resistor on the terminal too. So you pull the cap lead off, why not the resistor too?

As far as the resistors go, what do they cost? Maybe 14 cents each? Some you have to lift 1 leg to measure. Half way to replacing it already. So it measures on the high side tolerance and you don't replace it. Same situation as a mica.

Also this is a hobby to me. I enjoy replacing those components, cleaning, painting, polishing, etc. This way, when I'm done with a restoration, most of the troublesome parts have been replaced with a modern (re: a better) component and I can expect a long life of excellent use.

I know some guys do a "restoration" by replacing just what is needed to get it going again. To me that is like putting 2 gallons in the tank when you can fill er up! But I'm not criticizing them it's just what they do. This is how I do my restorations. Everybody sees this hobby through their own set of eyes and gets out of it what they want to. Neither is right or wrong. But different approaches.

[Polaraligned]

I hear you. Micas rarely go bad, but I have been hearing more and more reports of them failing lately. As long as you are having fun, that is the most important thing. I was just curious. Great job on the restoration.

[Crist Rigott]

Originally Posted by Polaraligned

I hear you. Micas rarely go bad, but I have been hearing more and more reports of them failing lately. As long as you are having fun, that is the most important thing. I was just curious. Great job on the restoration.

Thank you.

[Electronic M]

Originally Posted by Crist Rigott

Because you have to replace all the electrolytics and paper caps, there were like maybe 6 micas left. They have been known to got bad. So why not replace them too? There cost isn't too much either. Also it eliminates problems down the road. Say a mica still works, but then several hours it decides to quit. Then you have to go back and pull the chassis, trouble shoot the problem, replace the mica, maybe do another alignment, then put it back together. Seems the risks and rewards aren't worth NOT replacing the micas. Also when replacing the paper caps, most of the time there is a resistor on the terminal too. So you pull the cap lead off, why not the resistor too?

As far as the resistors go, what do they cost? Maybe 14 cents each? Some you have to lift 1 leg to measure. Half way to replacing it already. So it measures on the high side tolerance and you don't replace it. Same situation as a mica.

Also this is a hobby to me. I enjoy replacing those components, cleaning, painting, polishing, etc. This way, when I'm done with a restoration, most of the troublesome parts have been replaced with a modern (re: a better) component and I can expect a long life of excellent use.

I know some guys do a "restoration" by replacing just what is needed to get it going again. To me that is like putting 2 gallons in the tank when you can fill er up! But I'm not criticizing them it's just what they do. This is how I do my restorations. Everybody sees this hobby through their own set of eyes and gets out of it what they want to. Neither is right or wrong. But different approaches.

"Another alignment"?...If you leave the original micas and resistors in the IF system it should never need an alignment after leaving the factory that made it. Micas known to go bad?...Yeah in SWEEP circuits that never need 'alignment', and aside from some early (630 era) RCAs non-sweep circuit micas are a rare exception....Changing IF micas is like swapping an engine in a GM car at 20K miles because you heard about this guy that bought a lemon that had it's block crack at 20K....Your putting a lot of time and effort into something that is a 1 in 1k issue that won't have significant odds of happening to your set for another 2-6 decades (depending on past & future storage conditions).

Resistors are a toss up I usually leave them till I've done a recap power up....Many sets are fine and have sustained years of regular use in my hands with original resistors, and often it is not worth the effort alone of changing them. Though I have had sets that spent years (decades?) outside where all resistors were off tolerance and drifty, and in that case shotgunning resistors was merited.

As for replacing just enough parts to make a set work: The merit of that depends on the age and (slightly on the) storage conditions of the set. Paper caps are like milk, film caps (such as orange drops) are like salt....Makers transitioned cap types around 1960 (there is about a 3 year margin of error by maker). Sets made before the transition need a full recap if they are to see any kind of regular duty...I can see powering up an original and if it works keeping it original and powering it up for a minute every few months to see if it still works, but expecting to last a half hour every week is unrealistic. Sets made after the transition often are somewhat immortal...They will often work as found and require approximately the same amount of maintenance as they would have in the first 5 years of their existence....That I feel is a reasonable expectation for a set of that vintage.
To me the most fun part of the hobby (except maybe for the hunt) is troubleshooting. So if a set becomes too reliable and never needs routine service it quickly fades into the wall paper. (Also every problem you solve with a shotgun is knowledge you missed the chance to learn.) I expect my daily use sets to need help every 6 months to 3 years (and it is usually something I can fix in an evening or less), and so did their original owners...IMHO If you can* achieve better than new reliability then you loose the experience of owning a classic and may as well have a box with a LCD flat panel set in it.

*I Honestly doubt you can since heat is the enemy of parts, and modern components by and large were not designed to bake in a tube set...It may be solid for 5-7 years of use but once you've baked the new parts long enough it will slide right back down hill.

[Crist Rigott]

Tom,

Like I said " Everybody sees this hobby through their own set of eyes and gets out of it what they want to. Neither is right or wrong. But different approaches."

[Electronic M]

Originally Posted by Crist Rigott

Tom,

Like I said " Everybody sees this hobby through their own set of eyes and gets out of it what they want to. Neither is right or wrong. But different approaches."

True, and if nothing else you've explored an interesting and unconventional approach to circuitry restoration in tube TVs. It definitely is a case study I can see people referencing when a majority of micas start to hit their expiration date.

[Crist Rigott]

I'm glad I can be of some help to other people. I have certainly gotten a lot of help from others on this forum.

[reichsrundfu]

Not so fast buckos! Micas arr starting to go bad with a lot more frequency today. Ask me how I know this..

George

[Electronic M]

Originally Posted by reichsrundfu

Not so fast buckos! Micas arr starting to go bad with a lot more frequency today. Ask me how I know this..

George

Are you taking about sweep stage micas, IF stage micas or all micas? Sweep micas have been known issues in TVs for years (if you put 400-1500V pulses through any cap it's life will shorten), but IF stage micas * are under very little strain (~120VDC+ a few mV of signal) and tend to be near 100 percent reliable (ignoring RCA 630 chassis).

*if you ignore the oddball ones in the IF cans that produce SMD.

In 99% of sets the IF micas are perfectly fine and will remain so...Sweep micas on the other hand if not bad are often a repair waiting to happen.

[Gregb]

I have found bad micas in the RF section of a tube radio. I used to just ASSUME they are good but after a few trouble shooting bouts I no longer feel that way.

Gregb

[robert1]

Regarding the commonly used Micamold, Sangamo, & Aerovox mica capacitors (low capacitance), These too, are injection molded capacitors & can also fail the same way as the larger paper capacitors. that is because of moisture can penetrate them & contaminate the foil that is used in them & cause it to deteriorate. although there may be no DC leakage unlike the paper types, the capacitance will change. i have seen this many times in recent years.

[reichsrundfu]

Originally Posted by Electronic M

Are you taking about sweep stage micas, IF stage micas or all micas? Sweep micas have been known issues in TVs for years (if you put 400-1500V pulses through any cap it's life will shorten), but IF stage micas * are under very little strain (~120VDC+ a few mV of signal) and tend to be near 100 percent reliable (ignoring RCA 630 chassis).

*if you ignore the oddball ones in the IF cans that produce SMD.

In 99% of sets the IF micas are perfectly fine and will remain so...Sweep micas on the other hand if not bad are often a repair waiting to happen.

I've seen it in both.

George