My Christmas day 9T246 restoration! Almost.....

[Penthode]

Thank you for the replies! I respect your disagreements. The philosophy of simply replacing a component because everyone does it seems odd to me. I have seen my share of bad electrolytics. I just want to point out you can easily test and measure whether an electrolytic will hold up and whether it is good or bad.

The test is simple: reform the dielectric and measure the leakage current and capacitance. The reforming of a capacitor takes a few hours and I will put the full rated DC across it for a few days. If the leakage is more than 200uA, then it must be replaced. 200uA is far below the point of creating any heat dissapation from the capacitor. If you detect a 450v capacitor getting warm, then the leakage will more like 10000uA or above.

The RCA set capacitors used from the KCS28 chassis upwards are extremely good. Of the six sets of the late forties and early fifties vintage I have restored over the last 40 years, I have replaced two electrolytics. And the ones replaced never shorted, they became open. I have never had an old electrolytic explode as a result of the precautions I have taken. I have however seen newer capacitors explode.

The measure of pulling one apart and it looking crumbly and bad is no judge of its condition. Dry electrolytics use a dry paste and even a good one will crumble upon taking it apart.

Then again if you feel uncomfortable about this, by all means pull the old capacitor apart and stick in newer replacements. Also, if someone has been foolhardy to plug in the set after it has remained doment for 40 years, then you should expect explosions and fireworks. By my monitoring procedure I will find if a capacitor has been stressed.

I would just like to reitterate that I find it unfortunate that the assumption is that a component must be replaced without even testing the component to see if it is bad.