Rca 621TS

[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.

[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.

[Crist Rigott]

I worked on the Horizontal and Vertical sections today. They have been recapped and recarbed for the most part. I forgot to take a picture of my progress before starting this post.

Here is a picture of what I was working with. Caps and resistors seemingly wired "in the air"!


Anyway here is a picture of the picture as of tonight. Some change. Getting better. I think the audio will have to be aligned before I get any audio that matches the CRT.



Next up the Sync Separator and on to the Audio section.

[Crist Rigott]

Here is a after picture of what was worked last night.

[Crist Rigott]

I finished with the Sync Separator and audio sections. All sections are done except the IF strip and tuner. I still have to go through the back chassis control pots to clean them up and check them.

Here is a picture of the completed Sync section.


And the audio section:

[Crist Rigott]

I did the IF strip today. The chassis is basically been re-capped etc.



I installed some Y2 safety caps and one of them went to the switched AC power from the on-off switch to the transformer. Remember when I redid the volume pot? The one wire was chaffed pretty good on the chassis and I cut out that section and installed about a 4 inch piece of new wire under the chassis. That wire was the one that needed the safety cap. I installed a terminal strip and spliced a wire into the switched AC power and ran it to the terminal strip. I then installed the safety cap.






I'm in the middle of cleaning, lubing, and checking the back panel pots. When those are done, then the speaker and mount gets cleaned up and re-installed.

BTW, I have a APB for a electrical dual coil Ion Trap in the classifieds. Mine came with a resistor across the leads and a Dual PM Ion Trap.

[miniman82]

Yours for the cost of postage.

[Crist Rigott]

Originally Posted by miniman82

Yours for the cost of postage.

Check your PM. Thanks.

[Crist Rigott]

The back panel pots are done. On to cleaning up the speaker, then the tuner.

[Crist Rigott]

I cleaned up the the speaker and re-installed it.

I then decided to clean up the bottom of the chassis a bit. Cleaning up the dirt, rosin splashes, etc. I was thinking how can I get down into the tight spots with my Q-Tips? Then I had the idea of making an extension. One thing about Q-Tips is that they bend when you're really trying to scrub something clean. My extension worked perfectly!

Here are the details.

I used a piece of 5/32 aluminum tubing by K&S. You can get the tubing at a hobby shop, or hardware store. Not sure if Lowe's or Home Depot has this stuff. I then used my round nosed pliers to crimp some detents. I crimped twice and the second set of crimps was 90 degrees to the first and about 3/8 between them. I cut a Q-Tip in half using my cutters and then I push the Q-Tip into the tubing. The detents hold the Q-Tip in place yet it is easily removed and another inserted. The aluminum tubing is small enough in diameter to get the Q-Tip down into some pretty small places.

Another thing I tried with my cleaning tool was to use some lacquer thinner to clean. I used acetone before but lacquer thinner works much better. From now on I'll use lacquer thinner to clean off the rosin on a newly soldered joint.

Here are some pics to show you what I mean.

A close up of the crimped end.


Q-Tips and tubing.


Ready to dip into the lacquer thinner!

[Crist Rigott]

Finished the tuner today. I managed to changed out all the resisters. I changed out the shielded wire for some nice aircraft grade wire.

I'm almost done with the chassis. Left to do is the doorknob cap, finish mounting the high power resistor in the HV cage when the parts arrive, the dual coil Ion Trap has to be installed, mount a fuse block, and use the correct hardware for the yoke mount.

[Crist Rigott]

Took care of some details and this is the picture I have. It seems that the vertical sweep isn't high enough. I changed out the V. Osc and V. output tube (6SN7GT). My V. height pot is maxed and my V. Lin pot is very near maxed out (full CW). There appears to be some rollover at the top. B+ checks very good, HV is very good. I double-checked the component locations and values and they are correct.

Any ideas?

Here is MeTV:


Here is my 4:3 test pattern:


And here is video:

[miniman82]

Most common offenders tend to be drifted height/lin pots, but you can also futz with the values of the dropping resistors feeding the vertical section B+ to squeeze more height out of it. I have to do that with color sets sometimes, not sure why. For example if there's a 1.8 meg fixed resistor feeding boost voltage to the vertical section and it's in spec but the picture isn't tall enough, I'll stick a 1 meg in there and see what happens. Could be that the magnetic parts of the circuit like output transformer are getting tired, so compensation is required. Not sure, but it seems like giving it a little more voltage to work with is a sensible solution.

[Electronic M]

Originally Posted by Crist Rigott

Took care of some details and this is the picture I have. It seems that the vertical sweep isn't high enough. I changed out the V. Osc and V. output tube (6SN7GT). My V. height pot is maxed and my V. Lin pot is very near maxed out (full CW). There appears to be some rollover at the top. B+ checks very good, HV is very good. I double-checked the component locations and values and they are correct.

Any ideas?

Here is MeTV:

You see the ~4 dashes above the man's head, and the 1 above the kid's head? those are closed captioning data which is placed at the VERY top of the picture...The bright part of the picture should be ~3-10 horizontal scan lines away, but is is not (it is much farther). Your video source is giving you a letter boxed and pillar boxed signal (you can see the extra horizontal black bar faintly on the left side as well). It looks like the below where the picture is shrunk by the signal source and black is added around the edges (please excuse the lack of right perimeter VK's posting system dislikes ASCII art making a right border impossible).

_______________
| b  ___________ 
| l | picture      
| a |                
| k |___________
|______________