[Skip]

I am working on my 15X, not sure which production run I have, only number I found on the chassis begins with E61. Below is what I have done so far:

•Replaced all caps and resistors, except #66 (50Ω, 50Ω, 205Ω)

•Repaired an open primary coil on the second I.F. Now reads 4.5Ω, does that sound right?

•Jumped across an open coil on the shadow meter for now

The radio does play good, still need to peak the alignment.

I have some odd readings for the voltage on some of the tubes. I will start with the R.F. tube, below is the voltage readings took with a VTVM and 115AC line voltage:

P to K: 280vdc should be 165vdc
SG to K: 90vdc should be 55vdc
CG to K: 4.3vdc should be 15vdc
K to F: 9.7vdc should be 10vdc
Filament: 6.0ac

I have checked the caps and resistors, they look right based on the schematics I got from Chuck. So any idea where to start looking next?

http://www.nostalgiaair.org/PagesByModel...013138.pdf

[rghines1]

The power supply while filtered are not regulated. The B+ voltage is largely dependent on the load. The big load comes from the audio output section. If there is a bias problem or only half the push-pull is working that could explain a lot.

Make basic voltage checks on 42 output tubes with emphasis on the bias. Voltage chart is saying 15V of bias (K to CG). Low voltage on one of the plates could mean a open section in the audio output transformer.

[Skip]

Voltages across the 42’s look good:
• P to K: 273, SG to K: 284, Cg to K: 16, K to F: 16

Voltages across the 37’s look good except the K to F:
• P to K: 78 (1st) and 102 (2nd), Cg to K: 5, K to F: 6

Here are the other notable voltages, way outside of the specs:
• 1st Det CG to K: 3.9 should be .85
• OSC CG to K: 5.5 should be 15
• 2nd I.F. K to F: 6.0 should be 10

The audio transformer looks fine. Any idea what is dragging down my CG voltages? I am sure it is obvious but it is not clear to me yet.

[Skip]

Well I have checked each cap and resistor, all good and correct. I have traced each wire and check each coil, again all test fine. I have fixed the shadow meter and aligned the set. I still have voltages outside the norm. I am running the set at 115 AC and took all voltage tests with a VTVM. Below is what the manual says the voltages should be and what I have tested. Most are within specs but the RF tube volts are very high. The radio plays very well and sounds good, just wondering why my voltages are way out of spec. Am I just chasing ghost and should leave it alone?

   

   

[Steve Davis]

Skip, your VTVM does not load the circuit as much as the low impedance meters used back when your radio was built. This can give some unexpectedly high readings.

Steve