This is Part 2 in this series on this 1937 Grunow Teledial model 588. This radio was made around the time of the Hindenburg disaster.
In Part 1 we carefully checked out the radio's transformer to be sure it was not damaged, and then began carefully adding power through a current limited isolation power supply with additional fusing.
In this Part 2, we reinstalled the tubes and began to power the radio up. We were able to get the same conditions reported by the previous owner when he plugged it in: some tubes lit, but there was no sound from the the radio at all.
Let's start some in-depth troubleshooting on this radio by checking the field coil winding in the electromagnetic speaker, and then using signal tracing with a frequency generator. So where is the problem with this radio?
Please review the safety information in Part 1. Tube type equipment has very high voltage and is very dangerous. Take the time to research this for yourself. I mean this video for entertainment, not instruction; if you follow what I do, you are at your own risk.
References:
Excellent video discussing some basics of bench safety and power mains isolation by Mr Carlson's Lab: [ Ссылка ]
Grunow and Grunow Teledial are brands of General Household Utilities Co., Chicago, Ill. Closed 1938.
Frequency generator modification to add an inexpensive frequency counter:
Thanks Tony B. for the video and description - it works very well! Here is the link to the xraytonyb video (he also demos it by doing an alignment):
[ Ссылка ]
Vintage Signal tracer: EICO 147a
Modern Frequency/Signal Generator: Lodestar SG-4160B
Hindenburg disaster video: public domain at archive.org
Camera: Canon G7X Mark III
Mic: Rode VideoMicro
Video Editing Software: Power Director
