Resistor or jumper at hv rectifer socket: Zenith 25mc30

[Zenith6S321]

Ignore the test point from my previous post. I was thinking this was a 29JC20, so your test point is probably labeled differently.

Here are pictures from Goodman of the CRT pole piece positioning for roundies.

[Tubejunke]

Originally Posted by Zenith6S321

Ignore the test point from my previous post. I was thinking this was a 29JC20, so your test point is probably labeled differently.

Here are pictures from Goodman of the CRT pole piece positioning for roundies.

Wow, small world. I have those two shots in a (one of many) book I have called "Color TV Servicing Made Easy" by Wayne Lemons and Carl Babcoke. It's a Sams publication and is wonderful. Guess that makes me look pretty bad, but there is a method behind my madness.

The book simply says to position the clover "directly over the convergence pole pieces." It even shows what that is as seen in the electron gun breakdown. My question was derived from the fact that the area is blacked out where you don't see the pole pieces. The blackened area clearly ends about where the clover should be. I thought perhaps the black line could be a reference point placed as the pole pieces can't be seen. I'm not sure of the distance toward the yoke that this black area goes.

I am trying not to move things a lot as I have pretty decent color. I have moved the clover enough to see that it's placement forward or back even a small distance makes a big difference in alignment. I guess I may as well just slide everything back and see if I can view the pole pieces. After all, I could be having to put in a new crt and be removing all of this stuff anyway. I just thought that if this were an indexing mark it would be nice and useful too.

[Tubejunke]

I went ahead and just placed the plastic edge of the clover right at the metal disc for the pole pieces which is all you can see. I loosened the yoke and pulled it back and turned all but the red screen down and tried to move the rings to get a red splotch somewhere near center. Unfortunately, I can't get a red splotch at all as I have seen in some good YouTube videos by a member of VK. It seems I can conjure up all kinds of combinations of colors and even almost totally blue, but no red center.

So I just got it as red as I could and slid the yoke back. Definitely more to do there. I had to just further manipulate the rings at that point to get a somewhat uniform red screen. I really think that I need to get a degauss-er for one thing. I wonder if some magnetization could keep me from achieving the red center on that procedure....

[Electronic M]

Manually degauss, and if that fails move the yoke farther back (even if you temporarily have to slide the convergence yoke back a bit to make it work).

[Tubejunke]

Originally Posted by Electronic M

Manually degauss, and if that fails move the yoke farther back (even if you temporarily have to slide the convergence yoke back a bit to make it work).

OK, that sounds reasonable. I will try moving the yoke back as you said and see what happens. I don't have a degaussing coil, so I may as well try whatever I can. Those weak tubes I feel still have me waiting a long time for color, but at least I know that it will usually come in.

I have an RCA WR-64A color dot bar generator that I hooked up just for the heck of it and the thing worked for a few minutes and then my sync started going whacky. So I put it on my daily watcher and the same thing happened, which to me was good as it told me that it wasn't some issue with my old Zenith. I smacked it on the side (generator) and the sync problem went away. SO, I probably need to clean up some tube pins and sockets and I will have that rather handy unit ready.

Never a dull moment in this saga! BTW, I know they make DVDs now for alignment. I'm sort of a fan of vintage test/setup equipment and it was a gift, so I may as well put it to use.

[Electronic M]

If you can find a curbed 27" BPC TV set with a single large degauss coil, then you can salvage the coil from the BPC, loop that large coil into a ~15" smaller coil, and attach a cord to it, and use it as a degaussing coil. This ad-hock degauss coil may only last 1-5 minutes of 120Vac at a time before overheating so keep an eye on the temp and work fast if you use this method. I made a backup coil that way, and it works decently.

[Tubejunke]

GREAT! Moving the convergence clover back along with the yoke allowed me better purity adjustment. Not having a true technicians degaussing coil, I just got out my Weller soldering gun and used it like a coil. The trick worked great! I'm a bit embarrassed as to worrying so much about positioning my convergence clover perfectly. I have learned through trial and error that indeed we often need a pointer, but sometimes ya just gotta jump in there and see what things do.

If you are a tech or minded as such, then you know to mark and or document in some way the way things were before you moved or adjusted this or that. Our training or experience taught us not to go 'tweaking' this or that until you have reviewed some technical data and at least have a rudimentary understanding of what a device, circuit or adjustment of either will or does do. And when in doubt, ask a question. I don't know what it is with some of us, but we would rather noodle with a $10K piece of equipment and sometimes ruin it than to simply say I don't know for sure what is going on with this, anyone got some advice. Geez!

I saw that enough in the work place to not want to be 'that guy' and it's why I don't mind asking things that may sound ridiculous to some of the seasoned veterans of the golden era of electronics. I work on high dollar automation every day, but I need help sometimes with REAL electronics that's decades old. Having this place to gather that pool of knowledge is invaluable and a blessing. Thanks again to ALL here who have helped.

I thought someone might enjoy tonight's screen shot of Cream's reunion show at the Royal Albert Hall a few years ago. Ironically, it's where they did their "farewell" jaw dropping final performance back in 1968. I tell ya, audiences of today may as well be dead people compared to the crowd in 1968. The band more or less holds it's own to be the age they are now. Great DVD if your into Blues/Jam/Rock. They were their own unique genre.....

[dieseljeep]

Originally Posted by Electronic M

If you can find a curbed 27" BPC TV set with a single large degauss coil, then you can salvage the coil from the BPC, loop that large coil into a ~15" smaller coil, and attach a cord to it, and use it as a degaussing coil. This ad-hock degauss coil may only last 1-5 minutes of 120Vac at a time before overheating so keep an eye on the temp and work fast if you use this method. I made a backup coil that way, and it works decently.

I saw a lot of them made of aluminum wire. Doesn't really make any difference, just an observation of mine. It probably takes a few more turns to produce the same amount of flux.
Maybe taking a 60 or 100 watt lamp and connecting it in series would produce enough magnetic flux to be effective, without burning up.

[Electronic M]

Originally Posted by dieseljeep

I saw a lot of them made of aluminum wire. Doesn't really make any difference, just an observation of mine. It probably takes a few more turns to produce the same amount of flux.
Maybe taking a 60 or 100 watt lamp and connecting it in series would produce enough magnetic flux to be effective, without burning up.

A variac may also do the job of limiting heat....I just hold it the whole time, and if it feels like it's getting hot pull the plug. I've done enough degaussing procedures now that unless there is a particularly stubborn magnetized region it's usually one fast fluid ~30sec action.

Interesting that they use aluminum wire. I've never removed the black plastic wrapping to check.

[Tubejunke]

I still can't believe the job that my Weller model 8200 soldering gun did. Anyone ever tried this? I found it on the web as an alternative. I will say that it didn't hugely distort the raster the way a traditional degaussing coil does. Mine is 100/140 Watts. Not sure why it is listed that way.

[jr_tech]

Originally Posted by Tubejunke

I still can't believe the job that my Weller model 8200 soldering gun did. Anyone ever tried this? I found it on the web as an alternative. I will say that it didn't hugely distort the raster the way a traditional degaussing coil does. Mine is 100/140 Watts. Not sure why it is listed that way.

Pull trigger to the first click = 100 watts
Pull trigger to the second click = 140 watts

jr

[Tubejunke]

OK thanks! I think my gun is as dated as most of my equipment. The packaging looks 50s or 60s. Great to know!

[jr_tech]

Not to derail this thread too far, but here is a nice page about Weller guns... 60s is a good guess for a 8200.
My first Weller was given to me by my parents when I was a kid (late 50s)... a 8100 K set. Later (late 60s) it was lost/stolen and I replaced it with a 8200, which I still use on occasion. My favourite soldering tool for most stuff is a WTCPN station, also shown on the page:
http://www.stevenjohnson.com/soldering/weller.htm

jr

[dieseljeep]

Originally Posted by jr_tech

Not to derail this thread too far, but here is a nice page about Weller guns... 60s is a good guess for a 8200.
My first Weller was given to me by my parents when I was a kid (late 50s)... a 8100 K set. Later (late 60s) it was lost/stolen and I replaced it with a 8200, which I still use on occasion. My favourite soldering tool for most stuff is a WTCPN station, also shown on the page:
http://www.stevenjohnson.com/soldering/weller.htm

jr

I got my Weller 8100K for Christmas, December,1956. Man! Was I proud of that thing. The next gun, I bought was the Weller D440. 150/210 watts. It uses the 8100 tip and is ideal for most soldering. I think Weller quit making it in the late 60's. All the Weller guns I have now, came from garage and estate sales. I won't buy the newer ones with the set screws.

[DavGoodlin]

Originally Posted by dieseljeep

I got my Weller 8100K for Christmas, December,1956. Man! Was I proud of that thing. The next gun, I bought was the Weller D440. 150/210 watts. It uses the 8100 tip and is ideal for most soldering. I think Weller quit making it in the late 60's. All the Weller guns I have now, came from garage and estate sales. I won't buy the newer ones with the set screws.

My D440 has a few cracks in it but makes a great degausser in a pinch.
I got a near perfect 8200 for $10, tried to keep a poker face as I dug out a note