These sets are very difficult to work on. If you've tried, you will not forget the experience! They probably saved Philco big bucks, but became a headache for repairmen.

This design concept was the brain-child of David Grimes. Here is an excerpt from the Philco history website:

"His most notable contribution to Philco history was the 'Unit Construction' of the 1937 and 1938 models, using a separate RF sub-chassis housed in the center of the main chassis. He became Chief Engineer in 1941, and Vice-President in charge of engineering in 1942. He died in a plane crash in Northern Ireland on September 4, 1943."

If David Grimes' only contribution was the wedding-cake chassis, he would not rate for much, at least in my book. But wait.

Before his own company failed in the 1920s, he was a pioneer of the "inverse duplex" radio circuit, an example of which I am now working on. It was basically just a reflex radio, but his idea was to put the 2nd audio on the 1st RF tube, and the 1st audio on the 2nd RF stage. So, the lower-power RF tube is reflexed with the higher-power AF, and vice versa. Seems pretty obvious now, but it 1924, it was rather novel.

Later, as Philco's chief engineer, he died in a 1943 plane crash, supporting the U.S. war effort during WW2.

So, when we cuss those wedding-cake chassis, remember David Grimes.

:These sets are very difficult to work on. If you've tried, you will not forget the experience! They probably saved Philco big bucks, but became a headache for repairmen.
:
:This design concept was the brain-child of David Grimes. Here is an excerpt from the Philco history website:
:
:"His most notable contribution to Philco history was the 'Unit Construction' of the 1937 and 1938 models, using a separate RF sub-chassis housed in the center of the main chassis. He became Chief Engineer in 1941, and Vice-President in charge of engineering in 1942. He died in a plane crash in Northern Ireland on September 4, 1943."
:
:If David Grimes' only contribution was the wedding-cake chassis, he would not rate for much, at least in my book. But wait.
:
:Before his own company failed in the 1920s, he was a pioneer of the "inverse duplex" radio circuit, an example of which I am now working on. It was basically just a reflex radio, but his idea was to put the 2nd audio on the 1st RF tube, and the 1st audio on the 2nd RF stage. So, the lower-power RF tube is reflexed with the higher-power AF, and vice versa. Seems pretty obvious now, but it 1924, it was rather novel.
:
:Later, as Philco's chief engineer, he died in a 1943 plane crash, supporting the U.S. war effort during WW2.
:
:So, when we cuss those wedding-cake chassis, remember David Grimes.

I have an attorney's copy of that David Grimes patent (2,168,984) and have a small blurb on it in my Service Tip No. 2 regarding the Unit Construction servicing:

http://www.philcorepairbench.com/tips/svctip02.htm

Good concept for a manufacturer; lousy for service personnel, as we all can atest. :-)

Chuck