EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Hey Y'all, I am finally getting to finding out why my power supply is smoking.  When I pulled everything out of the cabinet I also found I do not have the 2 Voltage Regulators.  So if anyone has any for sale please let me know.  

Thanks

Mark

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Mark:  the regulators are NE42’s. A quick check of e-bay lists several sources available for them. I have restored one allwave 23, and will soon work on a second 23 chassis, that up until a week ago was working well. I have had the second radio since 2011, and it is complete in the Waverly cabinet. The one I just finished I got in 2015, and is the receiver only, no power supply or speaker.  It had been badly messed with, and the chrome is rough, but it came out well, better than I thought it would. 
Restoration of one of these is a major task, but with full documentation and careful work, the result is worth all the time and effort it takes, you will have a great radio when you are done. 
Thom. 

I doubt missing voltage regulators are related to a smoking power supply. The two VRs are in series and regulate the voltage only to the oscillator tube.

Be aware the speaker with good field coil must be plugged into the power supply as well as the receiver plugged into the power supply. Absent those loads, expect the amp B+ voltages to spike past design limits.

However, if you pull both rectifier tubes and without the speaker and set plugs inserted, then you can verify high voltages are present without damage to the power supply chassis. Be aware, an end-to-end voltage measurement of each high voltage winding will be very high, so be sure your meter is on a sufficiently high range, but safer to just check each to its center tap.

So, be sure you have a functional B+field coil in the speaker. And figure old filter caps should be replaced first.

Note that several of the filter caps negative ends are NOT connected to chassis ground, but to the "below ground" center tap lead of rectifier plate circuits. These certain filter caps were mounted originally on non-conductive washers to isolate them from the metal chassis. A mistake here will produce horrible sound and hum.

Lastly, check that the 100 MFD 50 volt filter cap has the POSITIVE end connected to CHASSIS ground, because the bias circuit off the rectifier center tap is below chassis ground.

Suggest using a Variac to apply moderate voltage to the radio and start checking for reasonable voltages trends in the major high voltage circuits before applying full voltage. It you use a dim bulb tester, use a 200 to 300 watt incandescent - I have used a vintage floor lamp with 3 way Mogul bulb.

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AND do you have that short cable on the speaker inserted in the correct socket on the speaker base? depends on whether you use the field coil tweeters - read the owners manual for this - available in the 

Scott Info Archives above, open Set Folders, select ALWAVE-23.

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