Rca 621TS

[old_coot88]

I would be leery of re-using that casing because of leakage concerns.

[Crist Rigott]

Originally Posted by old_coot88

I would be leery of re-using that casing because of leakage concerns.

Why? When I solder in a new cap where will it leak?

[old_coot88]

Now that the innard's exposed to ambient air/moisture, seems like it'd be prone to corona and arc-over inside. Or maybe I'm just being a fuddyduddy.

[Crist Rigott]

Originally Posted by old_coot88

Now that the innard's exposed to ambient air/moisture, seems like it'd be prone to corona and arc-over inside. Or maybe I'm just being a fuddyduddy.

Maybe you are. But we will see together when I get the caps in.

[Crist Rigott]

I reassembled the TV to power it up. As a recap of what was done so far, was to replace the E-Caps, clean the on-off volume pot, clean the brightness contrast pots, clean the V and H hold pots, clean the focus pot, replace some caps and resistors.
I powered it up using my variac and all seemed good using my 5AXP4 CRT. (EDITT: I then installed the 7DP4 CRT.) After a little warm up, I adjusted the Ion Trap and had a very bright raster. The HV is good! I could hear good audio from channel 6 a local FM station, but when I had a good picture from my converter box, there was no audio. I could hear static and some clicking. A lot of hash when I changed channels. I haven't gone through the audio section yet.
Over all a decent picture and good audio but not together. Of course I have a lot of caps and resistors to replace. I'll do some more power ups as I go through each section. And I haven't even touched the tuner yet.

Here is what I have now:


A composite of before and after:

[EdKozk2]

Hi Crist,
You said you heard clicking? Does it sound more like ticking, intermittent or continuous? I ask because if you stuffed the old doorknob with a modern ceramic or mica cap, you may have arcing between the cap leads. When I repaired my Admiral last fall I used a 15kv cap as a substitute for the old doorknob. When I first tested the set I would hear ticking. Lowering the brightness would increase the amount of ticking, increasing would decrease the amount. I had to operate the set on its' side and in darkness to see the source of the ticking. Turned out the gap between the capacitor leads right at the body of the cap needed a greater gap. The proper dressing of the leads solved the problem I had. I didn't reuse or stuff the old doorknob. I mounted the cap under the chassis.
Ed

[Crist Rigott]

Originally Posted by EdKozk2

Hi Crist,
You said you heard clicking? Does it sound more like ticking, intermittent or continuous? I ask because if you stuffed the old doorknob with a modern ceramic or mica cap, you may have arcing between the cap leads. When I repaired my Admiral last fall I used a 15kv cap as a substitute for the old doorknob. When I first tested the set I would hear ticking. Lowering the brightness would increase the amount of ticking, increasing would decrease the amount. I had to operate the set on its' side and in darkness to see the source of the ticking. Turned out the gap between the capacitor leads right at the body of the cap needed a greater gap. The proper dressing of the leads solved the problem I had. I didn't reuse or stuff the old doorknob. I mounted the cap under the chassis.
Ed

Ed,
The clicking I heard was as if a mica cap goes bad. I was touching the ceramic cap on the big coil on the tuner (I forget the name) and got the clicking sound. It also could be coming from somewhere else.

I didn't have the door knob cap installed at all. I'm still waiting for them to arrive. Good info though. Thanks.

BTW, the HV on this TV is listed as only 7.5Kv so the possibility of arcing between the 20Kv leads should be reduced by a lot.

[bandersen]

Originally Posted by Crist Rigott

...
I powered it up using my variac and all seemed good using my 5AXP4 CRT. After a little warm up, I adjusted the Ion Trap and had a very bright raster...

You don't use an ion trap or focus coil with a 5AXP4. They use a straight gun and are self focusing. Not having to mess around with the trap is very handy on the workbench.

[Crist Rigott]

Originally Posted by bandersen

You don't use an ion trap or focus coil with a 5AXP4. They use a straight gun and are self focusing. Not having to mess around with the trap is very handy on the workbench.

Bob,
You are correct. I didn't make my post very clear. I used the 5AXP4 for the initial power up, then switched to the 7DP4 and Ion trap.

I correct the post.
Thanks.

[Sandy G]

Originally Posted by old_coot88

Now that the innard's exposed to ambient air/moisture, seems like it'd be prone to corona and arc-over inside. Or maybe I'm just being a fuddyduddy.

Uhh, yeah...I'll be the 1st to admit that I know "Bupkis" about the ins & outs of this stuff, but on a set as rare & valuable as this one is, don't think I'd be trying to "cut Corners" or anything like that. Maybe searching 30 yrs B4 a 621 dropped into my lap, as it were, has made me a bit Jaded. That's just ME, however, YOUR experience likely is far different.

[Crist Rigott]

Originally Posted by old_coot88

I would be leery of re-using that casing because of leakage concerns.

You're right! In full disclosure the re-stuffed cap leaked. I didn't even mess with it. I took it out and replaced it with a similar cap. Oh well.

[decojoe67]

Originally Posted by Crist Rigott

You're right! In full disclosure the re-stuffed cap leaked. I didn't even mess with it. I took it out and replaced it with a similar cap. Oh well.

It certainly was a good try! I'm a novice, but would've expected it would have worked.

[Crist Rigott]

OK, I'm ready to do an alignment. I want to do the Video IF and Sound alignments. Any words of wisdom?

Thanks.

[miniman82]

If you have a crystal stabilized rig you can run through video first, then go through audio and make sure it matches up channel for channel. If you don't have crystal stability it doesn't much matter, since you'll likely wind up doing both multiple times till they get close.

[Crist Rigott]

OK, here is where I am on the alignment.

The video IF response curve is a bit peaked but I'm getting a great picture.
The audio curves look real good too.

When I'm playing a DVD the picture and sound are great.

When I'm OTA using my converter, the picture is great but the sound is pretty muffled. When I change channel 3 or 2 I get real good strong audio from the local FM stations.

I can't play OTA using channel because there is too much interference with the FM stations.

I tried adjusting the slug for channel 4 and the audio improved but there is still a marked difference between a DVD and OTA audio.

Any suggestions as to where to look? Does the tuner frequencies need tuning on channel 3 and 4?

Thanks.