Yeah, i was a bit perplexed too, not sure if the cap in question is just missing, or just in the wrong place. :scratch2:

I'm just a bit surprised it got any HV without it! :D

The schematic pic posted is from an RCA publication specifically for 9TC-240 model

I think the WD I'm using is a bit different. Same values but different component numbers

https://imagizer.imageshack.com/v2/1...922/GwzX7c.jpg

That's weird. The one I posted is specifically for this model too - KCS28B model 9TC240

Not surprising at all. It just means the yoke is disconnected. The HV comes from an autoformer on the primary side.

Bob can you show a slightly broader picture of the WD so I can see where C190 should be? I have a 0.47 there but IDK if it's hooked up correctly. I will install C199 as shown

C190 is about in the middle
https://live.staticflickr.com/65535/...960d7128_c.jpg

Did you download that from ETF? I plucked numerous service information packets off it and I don't have a wiring diagram that looks like your's.

It's from Riders volume 4 which is a reprint of the RCA service manual.

Don't have it. OK I'll just have to check through the schematic carefully and track my work. Thanks

What are you working from? Looks like original RCA service info. Is it for chassis KCS28 or 28A. Seems bizarre that RCA would publish two sets of service info with different part designators.

This...and the Sams. My chassis says it's a KCS 28B-1

https://imagizer.imageshack.com/v2/1...923/dOMmNc.jpg

https://imagizer.imageshack.com/v2/1...922/zVVLii.jpg

Right that only covers KCS-28. Your chassis is a later revision from the following year.

Just went for it. Looks OK...off center but OK :banana::banana::banana:

https://imagizer.imageshack.com/v2/1...924/bdEE2r.jpg

Any idea Bob where I can buy and download Riders Television service volumes?

Not sure. The guy who scanned them was selling DVDs on ebay for years. He had manual other manuals too at ke3gk.com

Could be he passed away?

Edit

Yep, Tom passed away a few years ago. Wonder what happened to all that scanned content?

That would be quite a find. I looked on eBay and found a volume 4 in decent shape for $30 including shipping. Like you, most of my restoration likes are in the post-war era

Cool! :D

major step forward, now if you can get video to show up, that would be another step forward!

I don't see any adjustment for centering on the schematics, so it must be purely mechanical, and no doubt will come into play when the 10BP4 is in place.

The picture is off center because the CRT is unsupported. Support the tube with a wooden frame or some books or something ensure the neck is centered in the focus coil and it will be much better.

Looks like he has a clamp on the CRT neck. I do the same.
Centering is mechanical by manipulating the focus coil. Do you still have it mounted? It will throw the 5AXP4 image off considerably.

No I removed it

I'd like to devise a way to 3D print a cylinder, about 2" long with an OD that fits in the yoke tunnel and an ID that will accommodate the 5AXP4 neck. The issue is the ID has to be big enough to slide over the base. If it does, then the neck won't be held in the center because there will be some play. Maybe making the ID big enough to get past the base and line the ID with adhesive foam will do the job. It wouldn't be designed to mount the CRT, just to center it. I'd still use the clamp.

It shouldn't really make that much difference though. I'm literally working on one right now with the same setup.

Can you grab the CRT base while the set is running and move it around a little? Can you center the image?

https://live.staticflickr.com/65535/...42f84ec1_c.jpg

The 5AXP4 and 10BP4 have the same neck diameter from what I see, so the only issue is how the yoke meets to the 5AXP4 and it having no support, this all should be minor stuff in the debug stage, as Bob suggested, just shift it till it is centered.
No where near as tricky as with the 8YP4 I have, :p, for that I did have to use a cardboard spacer, as it has a thin neck.

I use a large clip-on clamp on the neck. Fully supported and snug against the yoke. Works just as well with the 8XP4.
https://live.staticflickr.com/65535/...bf8f02d7_c.jpg

I managed to get the image centered but not low enough. I did expect it to move more when I wiggled it but...it's not great but it's better than it was. I can tilt the image if I roll the yoke left or right. I do have a signal passing through that's horizontally stable but rolls and wont vertically lock and the crosshatch is mostly bunched at the bottom of the image...but I still have several caps to replace in the vertical circuit so, I'll get that done and we'll see where we are.

So, I don't know if there was a consensus regarding the TV/Phono switch. Since grounding the 3rd tab on the brightness control got light on the screen, does that indicate the selection switch is bad and should be repaired/replaced or removed from the circuit? I have no intention of using the phono RCA jack for mono audio amplification so if disabling it is the easier route, I'll do that. Any long term performance or safety issue with soldering in a wire from the brightness control to ground for a permanent solution?

Thanks Guys

No, none at all. The switch is supposed to connect the 3rd tab to ground. That's why I suggested you bypass it.

Better. The vertical hold is quite touchy though. I don't have all the NOS tubes I ordered yet.

https://imagizer.imageshack.com/v2/1...923/hZcp5N.jpg

I have no audio. The speaker pops when I move tubes around so I think the output transformer is OK. Other than that it's completely silent.

Could the switch be causing this? If the switch was killing the brightness, could it be diverting the phono input to the volume control and disabling the TV audio? Only issue with this theory is the speaker is still silent if I touch and probe the phono RCA jack on the back with a metal screwdriver.

Yes it absolutely could be

Fine Tuning Challenge
 

Seems like the best thing would be a fabric belt like the original because these bands slip and have backlash as the stretch from winding relaxes and moves the fine tuning wheel a slight amount. But it's the best thing I can find at this time. I used two 2 1/2" X 1/3" bands held together with a little super glue.

https://imagizer.imageshack.com/v2/1...922/rBZjLM.jpg

https://imagizer.imageshack.com/v2/1...924/MSyoc0.jpg

How in the world do you clean this tuner? It’s in a bank vault!

You have to disconnect the wires and unmount it. I wouldn't bother unless you are having problems.

https://live.staticflickr.com/65535/...57cb1f1d_z.jpg

https://live.staticflickr.com/65535/...f3f68691_z.jpg

Yeah…not gonna do that. It’s just stiff and feels like it has a lot of gunk in there. Maybe I’ll spray a bit of contact cleaner in through one of the holes and be done with it.

Couple more questions
 

I'd like some advice regarding removal of the TV/Phono switch from the circuit. It's not exactly part of the title of this thread but I don't want to start another thread on the same TV...if I understand SOP here. If I should move this to the start of a separate thread, then please let me know.

Yesterday, the Riders service manual I purchased, Volume 4, arrived at my house. In it is the wiring diagram and schematic for the 9TC-240 with the KCS28B1 chassis. The switch on the wiring diagram and schematic is pictured below.

https://imagizer.imageshack.com/v2/8...924/zkvyw5.jpg

https://imagizer.imageshack.com/v2/8...922/idADzx.jpg

So if I understand what has been described earlier in the thread, if the switch is moved to the phono position, the TV brightness control ground is interrupted and the screen goes dark. There's still HV however. The sound circuit then comes out of pin 5 of the 6AL5 discriminator as coaxial to the switch where it picks up audio input from the RCA jack and is brought back into the sound circuit as a grounded coax line. Around there I get lost! To me it seems the signal goes to terminal 3 of the volume control and out of terminal 2 as coax to pin 1 of the 6AV6 bias clamp???

Below is the WD at the volume control.

https://imagizer.imageshack.com/v2/8...923/iAgDx6.jpg

The yellow and green coax are from the switch.

I need to understand how this all works with the goal being removal of all the switch wiring and circuitry interruptions. I'd like to just cut it all out and wire the sound like any TV would be without this feature.

Yes, pretty much. They way the drew the switch is a little confusing. The switch element go left/right not up/down.

* Ground lug 3 of the brightness control.

* Connect the two ends of the coax together so that the end of R215 is going to C184.

That's what I thought looking at it. So all the capacitor and coaxial stuff going on around the volume control, all of that stays in place? That's where I got lost!?

https://imagizer.imageshack.com/v2/8...923/iAgDx6.jpg

I guess all that stays there. Just do the coax link at the level of the tube bottoms in the chassis

...and my "Noobieness" exposed...how are these pot terminals numbered again? Are they depicted from the back, non shaft side of the pot? What is that fourth terminal coming out the side of the volume pot?

Once I get sound and a decent picture on the 10BP4, I'd like to do a basic alignment on the sound and video IF circuits just to make certain everything is OK and for my own experience. I've never been able to do one successfully before. Bob, I watched your recent video doing the sound align and all of the changes small movement of the adjustment coils made in the symmetry of the traces. I certainly don't have your HP monster on my bench but I do have an Eico 369 sweep generator that can do the 20-25 mc frequencies needed. I also have a decent HP scope from the mid 1980s. I'll probably start it as a separate thread. Your alignment series on YouTube was very informative but there were some Noob things I didn't understand so as I start that process, I'll be asking the choir for their help and guidance.