Are the above items really must haves when working on tube radios? Just wondering, I have done some work to a old motorola, without the aides of these... But only after discharging the electrolytics, and of course unplugging the radio.. If it sounds like a dumb question then let me know.. If not, then is the aforementioned items for testing your work?

:Are the above items really must haves when working on tube radios? Just wondering, I have done some work to a old motorola, without the aides of these... But only after discharging the electrolytics, and of course unplugging the radio.. If it sounds like a dumb question then let me know.. If not, then is the aforementioned items for testing your work?

Jesse:

I guess its a matter of preference. The variac is useful to bring up radios to full power slowly which can help check for shorts and let the old electrolytics re-form if possible. They are also useful for testing curtain burner sets with a bad or missing resistor cord. You can certainly prevent serious damage to the set by using a variac. Of course, you can also use the "dim bulb test" to check the power transformer. I got along without a variac for quite a while, so again its personal preference. Given a choice, I'd rather have one and they are relatively inexpensive.

The isolation transformer is another issue. This is really a safety item, especially with AC/DC sets. Its easy to burn up vintage test equipment without one, as well as getting a deadly shock. I consider both of the above pieces of equipment as "basic" and still use a GFCI circuit as additional protection.
Just my opinion, others may feel differently.

Regards,

Allan

Being new to old radios, I wouldn't work on a radio without them.

:Are the above items really must haves when working on tube radios? Just wondering, I have done some work to a old motorola, without the aides of these... But only after discharging the electrolytics, and of course unplugging the radio.. If it sounds like a dumb question then let me know.. If not, then is the aforementioned items for testing your work?

:Being new to old radios, I wouldn't work on a radio without them.
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If you don't want to purchase the above items, at least get a series light bulb and a GFCI from your local Home Depot (or whatever) and run the workbench through that. They are only about 7-8 bucks, and will lighten the shock considerably if you get caught between hot and ground. The series light bulb will perhaps keep you from generating expensive "magic smoke"
Lewis

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::Are the above items really must haves when working on tube radios? Just wondering, I have done some work to a old motorola, without the aides of these... But only after discharging the electrolytics, and of course unplugging the radio.. If it sounds like a dumb question then let me know.. If not, then is the aforementioned items for testing your work?

Hi Jesse,

One of the most important pieces of equipment on my bench is an isolation transformer. I never work on a radio unless it is iosolated from the power lines.

This protects you from a serious shock and potects your test equipment as well.

When I start a restoration, the first 2 things I do are:
1. On radios without power transformers I change the power cord to a polarized cord, ensuring the polarity is correct. (white (neutral) is connected to chassis).

NOTE: Also check your bench and make sure polarity is correct there.

2. Install a fuse in the radio. Normally I use a pig-tail fuse. I calculate the rating based on the power rating of the radio. This information is usually on the name plate.

Gary

:Are the above items really must haves when working on tube radios? Just wondering, I have done some work to a old motorola, without the aides of these... But only after discharging the electrolytics, and of course unplugging the radio.. If it sounds like a dumb question then let me know.. If not, then is the aforementioned items for testing your work?

Jesse,
I solved both problems with a US(120VAC)/European(240VAC) transformer backward, but only for transformer/switch tests, and no tubes. If all voltages are about half of normal up to the rectifier plates socket pins, then all should be well when full line is supplied.

marv

:Are the above items really must haves when working on tube radios? Just wondering, I have done some work to a old motorola, without the aides of these... But only after discharging the electrolytics, and of course unplugging the radio.. If it sounds like a dumb question then let me know.. If not, then is the aforementioned items for testing your work?