• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

roberts c r portable


2012-07-16 8:56 pm
Hello all.

I have been working on this Roberts c r portable and its very deaf.
I can only tune in 2 stations and it volume cranked flat out to get a whisper.
I have replaced its DAF91 and DL94 with new ones .
I have replaced all of the caps and most of resistors.
I am curious about the selenium rectifier,its outputting 60v dc and wanted to know if this would be too low for good operation,as its a 90v ht battery/mains set.

The LT is good at 1.4v dc


2012-07-16 8:56 pm
No they are way of on the dl94 the schematic show 81 anode and it has 51 and its screen 85 and it 0.6.
the daf91 its anode should be 11 and its 18.its screen should be 4v and its .003.

df91 should have 85 anode and its 52,its screen should be 28 and its 0.2