Emerson U4B

7/21/2009 3:15:09 AMVinny

Greetings to all,

I have an Emerson U4B (Chassis type) http://www.radiomuseum.org/r/emerson_chassis_u4b.html

According to Radio Museum (“This model is named like its chassis. The chassis is also used in models 118, 120, 126”). So there is no model#, just chassis U4B.

My question is:
According to schematics, (http://www.nostalgiaair.org/Resources/555/M0004555.htm) 118,120,126,
there is a Combination bypass filter and combination block C5,C9,C10,C11, ---Are these electrolytics????
In the radio chassis there is what appears to be a hard cardboard box with the readings—
16-8 MFD 150WV and 5-5 MFD 25WV

This radio chassis also has a 20MFD Electrolytic 150WV, I do not see it on the schematic however.

Vinny A

7/21/2009 6:24:45 AMEdd

Sir Vinny. . . .

HEY ! your set choices are getting more "antiquated", lately . . .

Indeed, they are electrolytics, and enclosed is a mark up of their use, with C5 and C9 being cathode bypass electrolytics and C10 and C11 being the DC main power supply filters.

If my unit to be re-doing, I would be using modern day values of 22 ufd @ 150 VDC or above, in the power supply and 4.7 upwards to 10 ufd @ 25VDC for the cathode bypass functions.

This radio chassis also has a 20MFD Electrolytic 150WV, I do not see it on the schematic however.

I feel that at some time in the past, that the two power supply electrolytics were dropping in value and some one merely shunted one of them with the tubular electrolytic to bring any encroaching . . . . . HUMMMMMM . . . . .back down to an acceptable listening level.

73's de Edd

Mini-Schematic for the EMERSON U4 Chassis

7/21/2009 2:43:01 PMVinny

Dr. Edd,
Greetings, thank you for your help (again and again) and easier to read illustration. A great flea market find in great shape at $20 (I think); I believe a rarer radio than usual. The more antiquated the more beautiful and challenging with great learning potential.
As soon as I saw they were electrolytics I looked for the differential diagnostic key, I wanted to know what I missed. The symbol, I should have referred to the symbol chart I have in a book, I think I overlooked the symbol for lack of a (+/-) indicator. However, those symbols after careful review were different but appropriate. The electrolytic I found in the radio sent me down the wrong path and made me question if I had the correct schematic. A great learning post for me, refer to the schematic and read it carefully.
Dr. Edd, if I replace the schematic electrolytics with modern day values, should I remove rather than replace the electrolytic that was added but not on schematic, or do you think it was factory added from the get go?
Thank you again,
Vinny A.
P.S. Doc, do you take all insurances?

7/21/2009 9:07:59 PMVinny

Dr.Edd, now I know why there is a electrolytic (Paper) in the chassis and not on the schematic. One of the wires from the condenser block was cut and that electrolytic evidently was put in it's place. Now to trace out the others.
Vinny