motorola vt71 ts4j 3rd if issue- it wont light

[bandersen]

According to Sams, yes, pin 4 of V5 goes to pin 3 of V6 via a choke.

TS-18 is pretty darn similar but don't know if the tube wiring in that area is 100% the same.

[kramden66]

I see a resistor not a choke. I guess someone wired it wrong bypassing it and this would explain why the tube wont light.

[timmy]

IIRC I think that resistor is a 1 ohm between sockets. The ts18 versus the 4d or 4j are different, I would stick with a print of that chassis not others. But they are very similar .

[Zenith26kc20]

Looking at my schematic of a TS-4J, pin 4 of V4 goes to pin 4 of V5, connectd between those two is R-F-C L-46, a choke. Also on pin 4 of V4 is a 250mmf to ground. Does V-16 (6AL5) light?

[bandersen]

The chokes look a lot like resistors. Here's a photo of one of mine you can use for reference. It's hi-res and you can zoom in for a closer look: https://flic.kr/p/f3QtaC

Here I've circled a couple of the chokes.

[kramden66]

Ah ha thanks for the pic. One of those chokes Has a resistor on it like it was added and looking at this pic I can see it was wired wrong explaing wht it wont light. When I hook it right I will expect the house to light up lol. Ok I will update what happens for real.

[kramden66]

Thanks now the tube lights and there is a signal withe usual minor touch ups to make the buzz go away etc. I'd like to report that the house lit up too but it didn't.

[wa2ise]

The manufacturer may have decided that resistors were cheaper than coils, and it being a series string they probably had excess string voltage to burn off. The resistors were probably chosen to act like decoupling coils (resistance = coil reactance at the IF frequency) to avoid unwanted feedback in the IF strip. They'd then reduce the ohms of the dropping resistor between the high side of the powerline to the top tube of the heater string.

[kramden66]

This resistor looks like someone added it to the one choke so I checked the choke and its not open. .... also removing the resistor might increase the signal but wont know for sure till I do more....... I don't know how or why the choke was wired wrong but without that tube lighting there would be no signal.