Do I have bad flyback or Sams Photofact is wrong (Emerson 611 TV)

[soliman15]

Dear experts, I’m working on my first TV restoration and it is Emerson 611 with older tuner (has channel 1).
I still have no raster, but I do have high voltage, not sure how much but I have good spark. As I was going over the resistance measurements, I found that resistance of the flyback's high voltage windings is reading more than 10 times of what Sams Photofact is calling for.
In the attached schematics T4 is the flyback, as shown below it, the primary (on the left) should be 340 ohm (1 to 3) and 175 between 1 and 2 leaving 165 ohm between 2 and 3.
I’m measuring ~180 between 1 and 2 (good), and about 3000 ohm between 2 and 3?
My question is my flyback is bad or Sams Photofact is wrong.

I’m doubting Sams due to the following:
-Transformers go either short or open they don’t just go up in resistance value and keep working
-If what sams calls for is correct, the plat of the horizontal output tube (V20) will be at more that 50% if the HV which seems too much to me.

Your help is truly appreciated and stay home.. stay safe

[Electronic M]

There is a ~30% tolerance to winding resistance , but that reading doesn't make sense. Are you reading your meter correctly/is the meter accurate?
That reading is taken with a fuse and Lin coil in series... I'd check directly across the primary of the transformer and see what it measures.

How long is the spark? It should be 1/4- 1/2" long. If shorter you have HV issues. If the length is in that range you should have raster...has your CRT been tested for emission? Have you adjusted the ion trap? Is the grid cathode bias voltage on the CRT reasonable?...all those things can kill the raster despite perfect HV.

[soliman15]

Originally Posted by Electronic M

There is a ~30% tolerance to winding resistance , but that reading doesn't make sense. Are you reading your meter correctly/is the meter accurate?
That reading is taken with a fuse and Lin coil in series... I'd check directly across the primary of the transformer and see what it measures.

How long is the spark? It should be 1/4- 1/2" long. If shorter you have HV issues. If the length is in that range you should have raster...has your CRT been tested for emission? Have you adjusted the ion trap? Is the grid cathode bias voltage on the CRT reasonable?...all those things can kill the raster despite perfect HV.

Thank you so much for taking a look. The HV spark is more than 1/4 for sure, I did the resistance measurements with both tubes caps disconnected and the fuse removed using fluke MM.
Regarding the CRT I tested it and it tested good with emissions well in the green, I still have lots of work to do but I needed some assurance that the flyback is not bad as it is a show stopper.

[Electronic M]

You should not remove the fuses from your multimeter. The fuse in series I mentioned in my last post was a fuse in the TV shown as M8 on the schematic you posted. I was suggesting measuring resistance between terminals 1 and 3 on the flyback... checking resistance between those pins and terminal 2 is also not a bad idea since it will tell you which half of the winding has the most resistance.

The flyback is probably fine if you are able to draw a 1/4"+ arc off the top connector of the 1B3. You should also be able to draw the same arc off of the CRT end of the 1M R101...If not the resistor has opened (not uncommon) or there is a problem with the doorknob capacitor C88 (they can intermittently short under voltage), the 1B3 or it's heater supply (R100 can open).

If you have healthy arc at the CRT HV connection adjust the ion trap (rotate it 360 degrees and slide it fore and aft of it's current position while watching the screen for light...once it lights adjust it for brightest light) on the CRT neck in a dimly lit room with brightness set to max and contrast at 50% rotation. If adjusting the ion trap doesn't give you light check the CRT grid and cathode voltages (it may be useful to rotate brightness and contrast and give min and Max voltages varying those controls create) against those listed in the schematic and post schematic vs measured.

By the way have you replaced the electrolytic and paper dielectric capacitors yet? Running the set on original capacitors is dangerous to the other components.

[soliman15]

Originally Posted by Electronic M

You should not remove the fuses from your multimeter. The fuse in series I mentioned in my last post was a fuse in the TV shown as M8 on the schematic you posted. I was suggesting measuring resistance between terminals 1 and 3 on the flyback... checking resistance between those pins and terminal 2 is also not a bad idea since it will tell you which half of the winding has the most resistance.

Thanks Tom for taking the time to help. The fuse I was talking about is the one you have mentioned and the top part (2 to 3) of the flyback is the one reading high ~3000 ohm.

one thing I'm not sure about is if the CRT I have requires ion trap as I don't see any model number on it that I can find. anyways here is a picture of the electron gun which based on my limited knowledge requires the ion trap.

Regarding the capacitors I did replace all the electrolytic and paper ones.
thanks again Tom

[AlanInSitges]

All TVs from that era needed an ion trap; in your photo you can clearly see that the electron gun is pointing off at an angle. You'll need to find out which type of trap was used on your set and get one - they are available. I'd bet that's your problem.

[Electronic M]

Yeah there should be an ion trap in that picture but I don't see one. Bent gun CRTs will not light without an ion trap installed and properly adjusted. If you can't find one for sale I think I have spares of the single and double magnet type.

[soliman15]

Thanks guys, I do have the ion trap and just removed it to take a picture but as the TV has lots of work done on it in the past and the CRT is dated from 1959 (yes not 49) I'm not sure of anything.

Anyways just found that the screen is showing some light, can't say raster as it is supper dim that I have to have total darkness to see it and I can't see lines, looks like I have both vertical and horizontal deflections but the brightens is so low and blurry that I could not say I have picture. I checked all the controls and all are working and none could make it brighter.

To check for weak CRT I added brightener and ran the TV for some time but it did not make any difference so I removed it (hope that was not a bad idea)

I'm still suspecting low High Voltage and not sure what to do next as I checked all the components (tubes, resistors, pots, capacitors, coils....) in the horizontal and HV sections and they all seem to me good.

All troubleshooting suggestions are appreciated.

[Electronic M]

Check the CRT cathode and first grid voltages (all gun voltages should be checked but grid and cathode are the most important) in comparison to those listed in the schematic (vary brightness and contrast and see if what is listed in schematic falls inside the range the controls give)...if those voltages can't match the schematic then you need to figure out why.

Get a HV probe for your DMM or an HV meter. You need to know the value of the HV to see if it is low...

Have you optimized the ion trap for brightest picture?

You have what is considered to be a weak raster. Raster is a lit screen with horizontal and vertical deflection present. If focus is poor you won't be able to see individual scanines even if the set has an otherwise perfect picture. Poor focus on a 10BP4 CRT is either an incorrectly set focus control, bad to us coil positioning, or poor HV or gun bias issues.

[soliman15]

Thanks Tom, good timing as I just received the HV Probe that I have ordered recently. what I have found is not exactly what in the Sam's but not too far to indicate obvious problem, and here are what Sam's call for and what I have found (this when the contrast and brightness at minimum):
Cathode Grid 1. Grid 2
Sam's 2.7v 130v 240v
Actual 3.3v 136v 261v

the HV under these conditions is 8,900 v which is what the tube data sheet recommends, now when I crank the brightness to the maximum to get something on the screen the first grid voltage goes down to 8.6 v which seems correct but the HV drops down to about 6,700 v with about 700 v drop on the HV 1 M. Ohm filter resistor, indicating about 0.7 mA high voltage current. not sure if that is normal or not.

Other things I did, I tested all the tubes and in spite that they all tested good I swapped them all and rerun the voltage measurement but did not see any significant changes, in addition I checked all the components in the focus circuit including the focus coil and all seems to be fine.

[Electronic M]

The gun bias seems normal. The HV sag is interesting...I don't recall seeing HV sag due to anything but high gun current. High gun current should produce a bright picture unless the ion trap is misdirecting the current.
There are 2 things I would focus: on the trap adjustment and the 1M series HV resistor...those old carbon comp resistors can get flake in HV circuits from internal arcing and the like and despite measuring fine at 9V from a DMM not behave right at HV...I would either replace it or short it temporarily.
Have you adjusted the ion trap for max brightness? If you have you may want try to flipping the trap backwards and readjust...By backwards I mean reversing it such that the open end of cylinder the trap forms that usually faces the screen instead faces the CRT base. Sometimes these traps don't work optimally depending on which way they're facing on the CRT.

BTW what is your room lighting level and brightness expectation of this CRT? Early non-aluminized CRTs (which an ion trap usually indicates) were not meant to produce a visible raster with sun shining on the screen. Non-aluminized CRTs were meant to be used in subdued/romantic room light levels (ie no light shining directly on screen and enough light that your not tripping on the furniture, but not enough that you are comfortable reading paper media.

[soliman15]

Bingo, thank you so much for your help I was about to give up and glad that I did not just needed more time missing with ion trap. The picture is supper bright.

Back to the original question, yes the Sam's is wrong regarding the fly back winding resistance and several other things, so in my next restoration I'll take it with a grain of salt.

[Electronic M]

Happy to help. Glad it is working good now.

Always good to take Sam's with a grain of salt. I've found at least 3 genuine Sam's typos before (some have messed me up) and many undocumented production changes.