If you have a means to check it. Check it.Have a good gander at C521 when you can.
L4 to chassis groundMeasuring from L4 to R501 I get .2ohms
Still no illumination ?put in incandescent
65KOhmsWhat kind of resistance do you read between L1 and chassis ground now ?
Thats a problem... I would think it would have around 50 Ω. Figuring 15-18Ω per lamp. Times 3 = 45 to 55 Ω.65KOhms
L1 and L2 = ? Ω
L2 and L3 = ? Ω
L3 and L4 = ? Ω