:Hope someone can help me. I have just done a lot of work to a Zenith H725Z1. When received from ebay, bakelite cabinet broken. repaired that. Emptied the origional electrolytics from the can, restuffed, then re-capped with orange drops, as the chassis is fairly busy in some places. The Orange drops are a little smaller. Checked the resistors and they seemed to be in tolerance. Turned radio on, and plays well but the plate and screen DC voltages are really low. Output tube plate 67 volts and screen 56 volts insteald of 120 nd 90 respectively. All the other tube DC plate and screen voltage is down by the same comparable amount as the output tube. 35C5 in this chassis. tested the AC before going into the selenium rectifier and its 118 volts. Checked the DC on the other side, and it is 74 volts (To chassis ground). Took a carefull walk through the B+ to see if I could find a component out of tolerance, but have not found any.Checked all the components to chassis ground in that circuit, and cant find anything wrong.
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Selenium rectifiers have a naturally high drop in voltage, and they tend to go bad. Yours is bad; you will need to replace it with a modern rectifier, and also place a 5 watt resistor in series with the ouptut. You can start with a value of about 100 ohms and check B+; you may need to experiment a little to get the correct value.
Johnnysan-