Zenith 7S558 - Videokarma.org TV - Video

AlTinkster92 · #1 01-28-2016, 05:51 PM

Hi folks, kinda new in this Forum but active in AK. Thought I would ask a question. I have the radio that I bought (supposedly restored) off The auction site. I have not plugged it in for over 2 years. What size variac do I need to safely bring this radio up? Its the same radio shown in my avatar. Thanks very much. Also, is there anywhere close to Charlotte NC I could take this radio to have it looked at should I need to? AL

Electronic M · #2 01-28-2016, 08:10 PM

Any size. I've got a 2A variac, and I've used it with 4 and 5A loads. A variac is a variable auto-transformer Transformers main enemy is heat. You can run 1.5-3X rated continuous load on a transformer until it gets too hot to hold your hand on for 5 seconds (turn it off at that point), and no harm will come to the transformer or load. 3X load may reach overheat in 5 minutes, 1.5X load may give over 5 hours.

P=IV P=Power(in W), I=Current(in A) V=Voltage You can use rated wattage and line voltage to calculate current.

Some don't like this, but some dimmer switches can be used as a variac in a pinch.

Olorin67 · #3 01-29-2016, 10:13 AM

Another cheap way is the "dim bulb" tester, put an incandescent 100 watt or so light bulb in series with the set, or start smaller then go up. I've even used grid from an old toaster as a series load, to apply a bit more voltage, but still less than 120v. You can slo monitor the current the set draws as it warms up, the wattage rating on the radio will let you calculate what the 'normal' current draw for the set is. Sitting 2 years isn't that long, for a set that probably has already been recapped, it should be OK.

AlTinkster92 · #4 01-29-2016, 06:25 PM

Thanks guys, I love this radio and want to start enjoying it again. I didnt want to just plug it in and hope for the best. By the way, this has a Wave Magnet antenna in the bottom of the cabinet. They any good? Also, if I connect a long wire antenna does the antenna lead to the radio need to be grounded to the chassis? Hope I said that right.

Thanks! Al

Electronic M · #5 01-30-2016, 12:53 AM

The wave magnets are the next best thing to a long wire. You do not connect the long wire the the chassis, but rather an antenna terminal. The set may also have a ground terminal THAT is where you would connect a ground. A long wire may help with "DX" long range listening, and a ground may help, but unless you are in the exact middle of nowhere they should not be needed for local/regional reception. An antenna is more beneficial than a ground in most cases. If you plan to use a ground make sure (with the set on) there is no measurable voltage between the ground terminal of the radio and the ground you want to connect the radio to.

Titan1a · #6 01-30-2016, 01:48 AM

I highly recommend the CCrain twin-coil antenna. I does wonders for my 7S363!

AlTinkster92 · #7 01-30-2016, 05:59 PM

Thanks a bunch, the radio does have the connections for the wave antenna but when I used it last I sure didn't pull much in. I thinks I got 2 Hispanic local stations is all. When I get a variac and fire it up again we will see. I comparison. my GE Super radio pulls in stations very well, AL