Long time no see! And new tv: Stromberg-Carlson "Broadview"

i have NOT removed anything!


What next?

Picked up Sam's sheet
Replaced Hi V rect
Misc video tubes cleared

Has raster, no sound.

https://imgur.com/gallery/BloNXk0

Finally figured out how to get the chassis out.

Why is the HV rec not glowing inside the flyback housing?

[Electronic M]

The filament of the HV rect can only be seen from underneath and is not bright...the filament for it is powered off the flyback so no horizontal deflection = no glow.

The raster now flickers and it needs to be dark to see it, when you turn the contrast to an extreme you see a faint raster. If you turn the brightness knob the raster glows very bright some but then disappears.

Can I pick the brightness problem and work backwards, checking components, and the actual knob/switch? I forget what it is called, that raises/drops brightness.

How do you track whether enough voltage is getting to the crt?

Fun fact- this Stromberg has a replacement RCA Silverama 21" tube, same as the RCA console that I have. And the flyback has been replaced in the Stromberg.

[Notimetolooz]

You will need to replace the electrolytic capacitors as well as the paper capacitors. Some other components as needed. You also need a multimeter at a minimum.
The set really doesn't "work" yet.

I do have a multimeter, and some other good test equipment; vactube vm, oscope, vhf signal gen etc.

I think the smart thing to do is to trace each circuit using the pjotofact, test for capacitance and resistance, and move down the circuit. Is that a best practice?

[DavGoodlin]

I have a Hallicrafters of the same age as this SC that did this, after a complete recap. I thought I goofed in the video and DC restoration circuits.

Yet, I still did not try connecting RF and all it needed was a signal. The video was fine for a weak 12LP4, but under no signal, was almost black.

Try an analog signal before going any further.

[Electronic M]

The brightness drop sounds like HV sag. If it passes video you can confirm HV sag by watching the image expand as it goes dark.

If it is HV sag the horizontal should be recapped and the HV rectifier substituted.

All paper and Electrolytic capacitors should be changed, but do them 1-3 at a time and check performance between each group. It is easier to catch any mistakes you might make that way.

[Notimetolooz]

Originally Posted by BandDirector

I do have a multimeter, and some other good test equipment; vactube vm, oscope, vhf signal gen etc.

I think the smart thing to do is to trace each circuit using the pjotofact, test for capacitance and resistance, and move down the circuit. Is that a best practice?

That would be a way to do it. You also would become more acquainted with the circuits. Sort of an aid in learning.
However, capacitors as old as in this TV have a very high probability of being bad, not every one but most. Some bad parts cause big problems, some just cause lack of best performance. Some might be OK for the moment but soon fail. You can't tell unless you completely test each one, that takes a lot of time and effort. You really need to unsolder at least one lead to test a capacitor. You should test for capacitance and leakage at near rated voltage. The other approach is to replace all the electrolytic and "paper" internal construction (some types of paper caps have plastic cases) capacitors. Resistors are a bit more reliable and easier to test.

[Electronic M]

Originally Posted by Notimetolooz

That would be a way to do it. You also would become more acquainted with the circuits. Sort of an aid in learning.
However, capacitors as old as in this TV have a very high probability of being bad, not every one but most. Some bad parts cause big problems, some just cause lack of best performance. Some might be OK for the moment but soon fail. You can't tell unless you completely test each one, that takes a lot of time and effort. You really need to unsolder at least one lead to test a capacitor. You should test for capacitance and leakage at near rated voltage. The other approach is to replace all the electrolytic and "paper" internal construction (some types of paper caps have plastic cases) capacitors. Resistors are a bit more reliable and easier to test.

Really any cap that old should be considered shot even if it tests good. Case in point (on newer sets known for having better capacitors) I checked every lytic in my 1962 Zenith 29JC20 color set and over 2 months of regular service it blew a an original section I left in every week or two....till I eventually got pissed and changed all the lytics. Back when I was a poor college student and didn't get believe in online parts vendors I bought a NOS 3KV .001 tubular ceramic cap that the seller claimed was a film dielectric to replace the original 2KV .001 paper dielectric tubular ceramic in my CTC15 clone....it shorted in a few months and took out other stuff too.

Original caps in 50s sets like that should never be trusted and even the better 60s stuff can still crap out.

I am pretty sure a cracked flyback wheel won't make a crt jump up and shine, I think I made that happen trying to resolder the hv lead to the tube cap.

Oh well. Need to replace it. Now I can get over trying to just see it glow a bit and start the real work.

[Electronic M]

Originally Posted by BandDirector

I am pretty sure a cracked flyback wheel won't make a crt jump up and shine, I think I made that happen trying to resolder the hv lead to the tube cap.

Oh well. Need to replace it. Now I can get over trying to just see it glow a bit and start the real work.

Most flybacks windings of that era were covered in wax or tar as insulation. NOS flybacks can have that insulation cracked too.
It is no big deal that the insulation cracked the flybacks will work with it cracked perfectly fine (assuming no other problems in the flyback or horizontal system)...the worst that that might happen as a result of the crack is Corona or arcing between that point and ground....you can fix the crack by GENTLY removing any loose wax/tar around it (if there is any) and then smearing a bit of sensor safe automotive RTV silicone over the crack/bald spot.
Some flybacks that have gotten hot in opperation have melted that wax/tar coating clean off and work without it.
The key thing with flybacks is that they aren't open (check winding resistance against that listed in the sams for your model to confirm it isn't open), and don't have shorted turns (that can be checked with a ring test, but most people don't bother unless there are troubles post recap).

TLDR: your flyback is probably just fine, silicone the crack and start recapping the chassis.

[Notimetolooz]

He might mean that the HV lead broke off when he tried to resolder the rectifier tube cap.

[Electronic M]

Originally Posted by Notimetolooz

He might mean that the HV lead broke off when he tried to resolder the rectifier tube cap.

Possible. That also potentially can be fixed if he can find the winding end stub or get a solder joint on one of the wires a few turns away from it.