Horizontal Sweep Adjustment?
 

The horizontal went out of sync on my 1960 Emerson console,
I got a new Hor.Output tube, and now after the set warms up, it straightens out, but takes about ten minutes...

There is a Horizontal sweep adjustment on my schematic, which I never attempted before:

it says to connect a clip lead across the Horizontal Stabilizer Coil...

What does that mean? Do I use a wire with two alligator clips? Across what parts of the coil?
Thanks for any help!

Yes, a clip lead is a wire with a alligator clip on both ends. I believe the idea is to stop the tv signal sync from effecting the oscillator frequency, then adjusting the free running frequency to the right value. After removing the clip lead the oscillator will easily lock to the signal. Be very careful you will be in a dangerous part of the TV. I don't have a circuit diagram, (model #, chassis # ?) so I can't comment on where on the coil.

Why did you replace the output tube for a synch problem? The output tube should be replaced for lack of deflection width. And the OSCILLATOR tube (and horizontal AFC tube or SS diode pack) should substituted or replaced for horizontal synch problems.

does the horz hold user adj work?

Sorry, I probably didn't use the correct terms...

What happens is when I turn the set on, the screen has lots of lines, just like if the horizontal hold needs adjusting... after about 15 minutes, they get fewer and fewer then the picture pops in clear...
I replaced the Horizontal tube only because I tested it, and it failed the life test on my tube tester, so I thought that could be the culprit.
The Horizontal Hold adj. doesn't work till the set warms up for those 15 minutes...
Even still, after the picture pops in, the picture is shaky and the images bend to the left and right...

Probably a slight adjustment of the Horiz stabilizer coil would center the horizontal hold, however you say it's shaky in any case so possibly the horizontal AFC diode is bad, at least I would guess a set of that vintage uses a solid state diode, actually two diodes in one package in most cases.

They are usually a small rectangular plastic component with three legs.
Like these. http://www.ebay.com/itm/Qty-2-ECG-11...item1e9d2e8169

Just getting back to repairing this set...
Are these AFC diodes possible to find? Do I have to find NOS?
The schematic says I can use a: R-2749 or a 2N408.
I included a photo of the diode in the Emerson chassis right now...
Anyone know where I can get one?

You may be able to use a DVM in "diode" mode to test the diodes. One way should read around 0.3V, the other way an open circuit.

You could probably use a pair of 1N914 or such small signal diodes as replacements. Nothing special about the pair inside one package.

Took out the diode...the instructions for my multimeter were all in Chinese, so not sure which setting I should use to test the diode!

Just realized I don't have a "diode mode" on my meter...
So, I guess I should just replace it anyway.
If I get a pair of 1N914 diodes, how do I put them together?
There are 3 leads coming off the original diode... Or should I just look at the schematic and try to figure it out?

In all probability it's common-cathode*. Check the schematic to be sure. The banded (cathode) ends of the replacement diodes would go to the middle leg.
-
*Rarely seen are common-anode and series type.

Yes, it is a common cathode...
I installed these, just got them from Radioshk today.
No improvement, seems a little worse if anything.
I wonder If I bought the right diodes? They say: 1N914 1N4148

A few notes
First either your set is a 1964 or 5 or the diodes have been changed before
they have a date code of 1964 38th week.

Keep in mind for the future these come 3 ways. Common anode,
common cathode, & series. Common cathode is almost
always what is used.

If that dont do it a tube is next. If not a tube probably a cap is
drifting, watch out for the clear silver jobs. The tube should be cheap
compaired to a hoz out.

73 Zeno:smoke:

How's the vertical lock, nice and strong like it should be? Or drifty like the horizontal?

Vertical is working fine, like it should...
Since about two weeks ago, the picture will not lock in at all now;

When I first got this set working, even the slightest touch of the long plastic horizontal hold tube in the back would make the picture shake...
but it would be fine once you left it alone.

I put in the 1N4148 diodes, checked alot of resistors, replaced a few, and replaced a few small caps as well... still no difference.
I am wondering if I should just change all the caps in the horizontal circuit?
Maybe overkill, but it's always impossible to test any values accurately while they are in the circuit...

does the horz hold allow you to change the direction of the horz lines or just get more?

Dumb question, but you have subbed the h.oscillator tube, right?

Also my question!

When turned fully one way there are lines, and fully the other way, distorted images seem to move sideways...

Yes, I replaced it with a new 6CG7, didn't make a difference though...

Oh, be aware that it won't work right if you have the replacement diodes, one or both, in backwards. Carefully remove them from the circuit board (so traces don't peel up) and tack solder the old diode package back in.

You want to avoid creeping layers of errors and defects from making life harder.

Lets keep in mind what seems to be going on.
It seems when cold the pix has lots of lines.
This IS the hoz osc off freq. No question........
I assume as it warms there are less lines then the pix
comes in but is trying to float side to side & is very touchy.
First thing is to get the osc stable. Its probably a cap but
check all the resistors also. You can use freeze mist on the
caps. Just a little on one at a time. Too much can cause a
good cap to drift. After it warms back up move to the next cap.

After you get the osc stable if its still trying to move side to side
start checking around the diodes. Also there is a sample pulse
coming from the flyback to the phase ckt. Check that, resistors
are often stressed there.

If you can also post the hoz part of the schematic, a big help !

73 Zeno:smoke:

Okay, I took a short video of the horizontal not locking in...

https://www.youtube.com/watch?v=7Gtz...ature=youtu.be

I also added the horizontal section of the schematic...

I have replaced all capacitors, less disc caps, and replaced most of the resistors, and left in those that measured correctly.

I believe the diodes are installed correctly, the cathodes, (banded ends), as common, both ends I soldered in the middle , where the middle leg of the dual diode was soldered in. Replaced the Horiz. Oscil. tube, a few times with different strong tubes. I also used Deoxit in the hor/hold pot.
Nothing seems to be working?

this is why a video is needed. Its not the AFC diodes at all. The horz osc freq is way off and no amount of sync signal will help. in other words this is not a "locking in" issue. Locking in implies a horz freq that is near the correct freq but not synced up to the video sync signals.


I would suggest you put back what ever you took out there just to reduce the number of variables.

Next would be did you try adj the horz osc coil. if its working this should change the freq (and number of lines to fewer until it can be momemtary lock anyway).

Did you confirm the values of parts that have been replaced so far. Did you replace the cap across the horz hold coil. Did you confirm the value of that cap, did you make sure the replacement cap that was used was good?

did you make and adjustments to the trimmer cap? any parts that have been replaced should be double checked to make sure you did not make a 10x error.

EXACTLY !!

If you try the hoz coil first clean the customer control R6b &
put it dead center. Put a flag (piece of tape) on your alignment
tool so you can count the turns & go back if need be.

73 Zeno:smoke:

If the osc. coil is soldered to the board check for cold or cracked joints at it's terminals, I've had troubles with board mounted coils developing bad joints and strange problems resulted.

other thing to check, the horz hold pot, make sure one side is not open. I like to use analog meters to check the action as well as the continuity of the end terminals. Analog meter movement is a better tool for evaluating the action, than a digital meter. confrim the voltage divider resistors that feed it as well. Dont forget to confirm ground connection of that pot as well.

If the h.freq. coil has a hollow slug requiring a hex alignment tool ('diddle stick'), be sure the correct tool is used. Otherwise you'll fracture or split the slug making it impossible to turn.

The correct tool is plastic. DON'T use a metal hex key on slugs EVER.

Right you are. I shoulda mentioned the tool is plastic (nylon?).

hmmm if the sams says to clip a wire across the coil as part of the setup process, then I can presume its not really a horz freq adj as implied on the schematic, That plus the fact that it suddenly stopped working points away from the coil as an issue). a stabilizer is not the same as a freq adjustment coil.

You can try it but if you dont get instant changes the don't go tweeking. I really doubt its going to fix it.

Next up, was there any thing else that may have happened before it stopped working correctly? did you try to clean anything or do ANY other work or did you just turn it on and it stopped working?

I am presuming you already tried cleaning the pins of the sockets. The most likely error would seem to be in the feed back RC network OR the pot opening up somewhere.

Yeah, definitely recheck the reference pulse feedback loop. It goes thru a whole string of components (R81, R82, C54, C62). A break anywhere in the path, like a broken foil trace, would kill the pulse.

Thanks for all the good advise, as always!

Well, I did try to adjust both the horizontal drive, and frequency, neither made a difference.
There are not many resistors left to replace in the entire set, and I only have about 6 small ceramic caps I could replace in the Horizontal circuit, if by chance one of them may be bad...
I will also check the coil to make sure it's soldered well to the board, and no cracks anywhere... and check the hold pot with my meter...

I was also thinking, would the horizontal sweep typically have to be re adjusted after replacing caps and resistors and diodes?
If so, Sams gives me the procedure... Just not sure how to:
"clip a lead across the stabalizer coil"

I would do the procedure now. Cant find TP3, must
be at sync sep tube ? Probably the trimmer cap is
a coarse adjustment & the coil a fine adjustment.
L19 & C59 are a tank so they will oscillate when hit
with a pulse.

73 Zeno:smoke:

Took another look at the chassis today, and found this very thin cloth wire just sitting on top of the Horizontal multi trimmer loose...
The other end is fixed into the board.

Is this thread supposed to be connected to the trimmer and possibly broke off???

no.

Did you check the horz pot connections and did you confirm continuity of the pot end terminals?

That looks like coil wire. If your lucky it broke off the terminal.
If not it may have broke inside the coil. You need to pull the coil
& see if you can find the other end then make a new connection
to the proper terminal. Get any numbers off the coil while you have it
out also.

73 Zeno:smoke:

I guess that thin wire is just excess? It looks as though that wire I showed a photo of, starts where it looks "broken", goes up, is glued to the PC board, then comes back down, and into a small hole of the PC board...Yes...
I tried both the Hold, and local distance... both had continuity.
The Hor.Hold Pot read 7.05 on the end terminals, and when I tested on the center wiper and turned the pot, it went from 0... up to 7.05 with my multimeter set at 20K resistance.
I think it's a 10K pot, but unfortunately, even though my sams schematic shows basically the same chassis layout, there are different values, and some caps and resistors are in different places than my set...

I wish I could find the exact schematic for my set, but after looking for a long time, this was the closest sams had...

just check the coil with ohm meter, should be 45 per sams 1 and 3 I assume 2 and 4 are not used. You can test in circuit. You can check voltages as well, its the plate supply so if its open you would have zero.

Try not to replace any more parts until you cover the easy stuff, like voltage checks and resistance checks (see the sams for pin resistance readings).

The biggest mistake that can be made is LOTS of parts getting replaced in a shot gun manner as a method of repair. It can make for a real tough dog.

Did you go back and double check all the values of the replaced parts looking for a 10x change? did you spray any cleaning agents (specifically near that trimmer cap)?