I've noticed that a number of zenith consoles that I have
tend to have transformers that run in the upper end of warm after about an hour. Measuring them with a thermometer indicates them running about 120 degrees F.
Yet I have a couple that run notably cooler. I don't see any correlation between the radios that have had all or most of capacitors replaced and current draw seems within ratings. Anyone have thots on this? have you measured the running temperatures on these? Thanks

:I've noticed that a number of zenith consoles that I have
:tend to have transformers that run in the upper end of warm after about an hour. Measuring them with a thermometer indicates them running about 120 degrees F.
:Yet I have a couple that run notably cooler. I don't see any correlation between the radios that have had all or most of capacitors replaced and current draw seems within ratings. Anyone have thots on this? have you measured the running temperatures on these? Thanks

If you have 1920's radios they were made for 110 volt operation; the additiona 8 to 12 volts is enough to make them run hot.

::I've noticed that a number of zenith consoles that I have
::tend to have transformers that run in the upper end of warm after about an hour. Measuring them with a thermometer indicates them running about 120 degrees F.
::Yet I have a couple that run notably cooler. I don't see any correlation between the radios that have had all or most of capacitors replaced and current draw seems within ratings. Anyone have thots on this? have you measured the running temperatures on these? Thanks
:
:
:If you have 1920's radios they were made for 110 volt operation; the additiona 8 to 12 volts is enough to make them run hot.

Leno: You can build a cheap voltage reducer to run your radios designed for 110v and 117v. I did this for some of mine, and seems to work great. You can find the parts list and circuit diagram at: http://bama.sbc.edu/voltagereducer.htm
Steve

:::I've noticed that a number of zenith consoles that I have
:::tend to have transformers that run in the upper end of warm after about an hour. Measuring them with a thermometer indicates them running about 120 degrees F.
:::Yet I have a couple that run notably cooler. I don't see any correlation between the radios that have had all or most of capacitors replaced and current draw seems within ratings. Anyone have thots on this? have you measured the running temperatures on these? Thanks
::
::
::If you have 1920's radios they were made for 110 volt operation; the additiona 8 to 12 volts is enough to make them run hot.
:
:Leno: You can build a cheap voltage reducer to run your radios designed for 110v and 117v. I did this for some of mine, and seems to work great. You can find the parts list and circuit diagram at: http://bama.sbc.edu/voltagereducer.htm
:Steve

::::I've noticed that a number of zenith consoles that I have
::::tend to have transformers that run in the upper end of warm after about an hour. Measuring them with a thermometer indicates them running about 120 degrees F.
::::Yet I have a couple that run notably cooler. I don't see any correlation between the radios that have had all or most of capacitors replaced and current draw seems within ratings. Anyone have thots on this? have you measured the running temperatures on these? Thanks
:::
:::
:::If you have 1920's radios they were made for 110 volt operation; the additiona 8 to 12 volts is enough to make them run hot.
::
::Leno: You can build a cheap voltage reducer to run your radios designed for 110v and 117v. I did this for some of mine, and seems to work great. You can find the parts list and circuit diagram at: http://bama.sbc.edu/voltagereducer.htm
::Steve

I have a couple variations on the voltage reducer, altho the Bama site has a nice article and that is the more efficient design. I also include a 140 ohm neg temp coef thermister for a "soft" start. Bottom line, these
1930's radios are receiving about 112,113 volts altho the line voltage here is about 125. Just wondered if anyone else had given any serious thot to transformer temp. I also notice that the transformer in my Hallicrafters S-40a also runs about as warm on 110.
But I'm pretty sure those were run hard and continuously in real life. Just for add'l reference, I believe 140 degrees F is scalding and what you would regard as Hot water is about 120 degrees. 120 is typical temp for a lot of modern electrical gear.
Just curious. thanks

This brings up an interesting point - I had trouble aligning a Zenith tombstone and I got some "motorboating" and howling at the lower end of the AM band (but not SW bands). It had been recapped and open areas of the Candohm bypassed. I decided to try aligning again at 110VAC (I built a BAMA voltage reducer some years ago) Voila! It easily went into alignment and the "putt-putt" went away. I suspect there are some other resistances out of tolerance that become evident at higher voltages and I plan to go through the chassis once again very thoroughly.

:This brings up an interesting point - I had trouble aligning a Zenith tombstone and I got some "motorboating" and howling at the lower end of the AM band (but not SW bands). It had been recapped and open areas of the Candohm bypassed. I decided to try aligning again at 110VAC (I built a BAMA voltage reducer some years ago) Voila! It easily went into alignment and the "putt-putt" went away. I suspect there are some other resistances out of tolerance that become evident at higher voltages and I plan to go through the chassis once again very thoroughly.

I suspect that at somewhat higher voltages that interstage gain is higher also. I've noticed quite a difference between even 105 and 115 volts when bringing
a set up slowly on a variac.