I need instructions for alignment of a 1940 Zenith 6D525. I have the schematic and have replaced all the rubber-coated wiring, caps and outof spec resistors. I can receive a number of stations at a couple of places on the dial, so I want to check the alignmant but cannot find the instructions.

:I need instructions for alignment of a 1940 Zenith 6D525. I have the schematic and have replaced all the rubber-coated wiring, caps and outof spec resistors. I can receive a number of stations at a couple of places on the dial, so I want to check the alignmant but cannot find the instructions.

Hi David,

You may check on this site in resources for a Zenith 6D520 which has alignment data. It seems to be pretty much the same as the 6D525.

Radiodoc

::I need instructions for alignment of a 1940 Zenith 6D525. I have the schematic and have replaced all the rubber-coated wiring, caps and outof spec resistors. I can receive a number of stations at a couple of places on the dial, so I want to check the alignmant but cannot find the instructions.
:
:Hi David,
:
:You may check on this site in resources for a Zenith 6D520 which has alignment data. It seems to be pretty much the same as the 6D525.
:
:Radiodoc

Hey Doc,

Thanks, I printed the 6D520 schematic. The set looks very similar to mine and should work great. I appreciate the tip. Oh, one question, where do I hook the "ground" clip from my sig gen. I think the chassis is hot on this set.

David

Dave

:::I need instructions for alignment of a 1940 Zenith 6D525. I have the schematic and have replaced all the rubber-coated wiring, caps and outof spec resistors. I can receive a number of stations at a couple of places on the dial, so I want to check the alignmant but cannot find the instructions.
::
::Hi David,
::
::You may check on this site in resources for a Zenith 6D520 which has alignment data. It seems to be pretty much the same as the 6D525.
::
::Radiodoc
:
:Hey Doc,
:
:Thanks, I printed the 6D520 schematic. The set looks very similar to mine and should work great. I appreciate the tip. Oh, one question, where do I hook the "ground" clip from my sig gen. I think the chassis is hot on this set.
:
:David
:
:Dave

Hello David,

I would connect the ground clip to the radios B minus. On my 520 the electrolytic is mounted vertically on top of the chassis on an insulated electrolytic mounting plate. For alignment I connected my negative gen lead to one of electrolytic ground lugs. I don't remember if there were 3 or 4 lugs. These lugs are all connected together. One caution is in order. If your sig generator has a 3-wire cord it will be a good idea to use a 1-to-1 isolation transformer (120 V to 120V)to power the radio to prevent possible damage to the radio and/or the sig generator. I would replace C9 with a new cap of the same value and a voltage of at least 1000 volts.

Radiodoc

Though this is an AC-DC set, the chassis is isolated from the line via a condenser (C9). You may successfully connect the "ground" lead of your generator directly to the chassis provided that C9 is in good condition (no leakage). Though no damage would occur if this next measure was not undertaken, it is wise to plug in the radio so that the chassis is on the neutral side of the line. If it is not, you can introduce hum into the radio when the chassis is connected to the generator. Also, though you won't likely be killed, never touch the chassis and the generator or its associated leads at the same time. If the generator has alligator clips on the leads, connect the leads without touching the radio. Once the leads are connected, you may touch both with no troubles. If the radio is plugged in with the chassis on the cold side, there is no risk of shock, but if it is plugged in so that it's "hot," you can receive a nasty shock if you touch the generator leads and the chassis at the same time when they are not connected together.

An isolation transformer is always a plus, but by following the above directions, you may align your radio successfully without one even if your generator has a 3 wire cord with the ground wire connected to its chassis. I've aligned radios in this way many times with my generator, though as a precaution I disconnected the ground wire of its cord from its chassis. This way I could also align radios with chassis which are connected directly to the line. In this case, when I removed the ground wire from my generator, I connected a condenser to the chassis from the ground wire instead. Again, even with this modification, with either type of AC-DC radio (hot chassis or condenser isolated chassis), it is good practice to plug in the radio so that the chassis is on the neutral side. This eliminates shock risk and reduces hum problems.

If you do not quite understand what I have said above, it is wise to use an isolation transformer at all times.

Thomas

Thomas