Television 1960s 23" Weltblick 511TR

[Retro-guy]

Okay gonna try a different DY87 ...

Also a new problem has developed,I only have a raster now,the snow disappeared,but I know the tuners work cause I have perfect sound only
picture went away ,only white raster ,when I measured the voltage on the cathode of the CRT was only 14 V which is a bit low and pin 6 had 12 v instead of 80v and pin 9 had 260V instead of 210V

there is something weird going on in this TV ...

[Retro-guy]

Okay I did some further testing with it and hooked it up to the analog cable

I got perfect sound,works great only problem is picture is very weak,likes to shift up and down and there are multiple picture in the screen,when i disconnect the signal the snow comes up and is sop much brighter then the picture ...

Also the pcl84 SEEMS A BIT TOO hot,seems there are problems with the video amplifiers as well ,tuners seems to be working cause I have great sound .

were to investigate now ?? I have a scope,can that HELP ??

[Electronic M]

Have you tried adjusting the horizontal and vertical hold controls to try and get it to synch? If not, then do it.

Does your set have an 'AGC' control as we call it here in the USA? If it does try adjusting it. Miss-adjusted AGC can cause loss of synch, and poor contrast like your pictures show.

[Retro-guy]

The picture is basically cut and the two parts of the picture are switched,the bottom is on the top and top part is on the bottom as you can see more in pictures ...

Definitely has a problem with the video amplifiers and circuitry,focus and geometry is out of question at this moment !

It could either be the EHT,video amp or CRT voltages,on a grid there should be like 400V and was like 173V (measured with a multimeter)

NOW it does lock horizontally and vertically OK but the picture is still messed up not to mention the lack of contrast/brightness ...

Originally Posted by Electronic M

Have you tried adjusting the horizontal and vertical hold controls to try and get it to synch? If not, then do it.

Does your set have an 'AGC' control as we call it here in the USA? If it does try adjusting it. Miss-adjusted AGC can cause loss of synch, and poor contrast like your pictures show.

It doesn't have a AGC,I tried every adjustment on the set except for the if coils and pic related is the best I can come up with right now ...

HELP ...

[Electronic M]

It would appear that your sets vertical deflection circuit is operating at twice the proper frequency....It can obviously still synch but it is scanning the top half of the frame over the bottom half. I had this exact issue before once. What you need to do is replace all capacitors in the vertical circuit, and test all the resistors in the vertical to make sure all are within rated tolerance (if any are not in tolerance replace them obviously)....If that does not fix the issue, then get a resistance decade box and start trying different values in place resistors in that are in that circuit (which is what I had to resort to).

As for the brightness make sure the HV is correct, and the cathode grid and screen voltages are right. If any are wrong track down the problem in the circuits supplying it.

[Retro-guy]

Originally Posted by Electronic M

It would appear that your sets vertical deflection circuit is operating at twice the proper frequency....It can obviously still synch but it is scanning the top half of the frame over the bottom half. I had this exact issue before once. What you need to do is replace all capacitors in the vertical circuit, and test all the resistors in the vertical to make sure all are within rated tolerance (if any are not in tolerance replace them obviously)....If that does not fix the issue, then get a resistance decade box and start trying different values in place resistors in that are in that circuit (which is what I had to resort to).

As for the brightness make sure the HV is correct, and the cathode grid and screen voltages are right. If any are wrong track down the problem in the circuits supplying it.

Well I don't have a HV probe,there is no other way to test it right ?

To me all the caps look OK,all the paper ones were already replaced,there is a bunch
of polyester ones but they normally they don't go bad and I didn't even find one resistor off value only one that was open ...

There is another think I used a bit thicker wire to rewind the flyback secondary winding(0.30mm instead of 0.22mm wire) can that cause the EHT to be lower ??

[stusnyder]

I had a similar problem with a zenith. Try different IF tubes.

[Retro-guy]

There seems to be something seriously wrong with the line oscillation on this thing

Okay so now the PL504 sweep tube gently and slowly starts to red-plate (also it sounds like it clicks inside the tube)after 30 seconds of set turning on,which means the cathode current start to go a bit high,which could be caused by the oscillator running at a too high frequency ...(on pin 6 there is 160V and it should be 215V but I checked all resistor and they all fine)....

Now I suspect the two yellow diodes in the pic cause they are connected to the grid of the PCF801 and when I try-ed testing them,I got nothing on the meter,like they would be open,or was I doing something wrong ...


Also does the tube in pic look shot,its a mini-watt PCH200 AND IS CONNECTED DIRECTLY on the two yellow diodes ...IF you look the getter it has some sort of white stuff there,can that be a indication of a gassy/bad tube ??

PROBLEMS:

-cant get a clean picture,its cut and the two parts are switched around ,which could mean the oscillator is running too fast and if I try adjusting it there appear multiple pictures and the bleed into each other ...

-PL504 gently start redplate everything else from the EHT prospective seems to run fine,except for the blooming problem(could be the DY87,BUT THAT CANT AFFECT THE PICTURE PROBLEM)

-OSCILLATOR isn't running correctly and the high pitch is so loud that my ears hurt,which is another indication that it seems to run too high ...


I USED THICKER WIRE WHEN I WAS REWOUNDING THE FLYBACK SECONDARY WINDING,WHICH THE OSCILLATION FROM THE TUBES GOES THRU THESE WINDINGS ,CAN
THAT BE THE PROBLEM OF THE?,CAUSE OF THE CHANGE IN RESISTANCE AND STUFF ?? (0.30MM INSTEAD OF 0.22MM)

Originally Posted by stusnyder

I had a similar problem with a zenith. Try different IF tubes.

it has a solid state IF

[Electronic M]

Milk white getter means the tube has lost it's vacuum. What I see would indicate that the tube is either beginning to take on gas, or has been ran long and or hard enough to wear out the getther. I'd get a replacement for that tube or at least test it.

HO Tube redplating will quickly kill the HO tube. The horizontal appeared to be on frequency in the pictures you posted. If it is like the American Synchroguide horizontal oscillator circuit then it can be on frequency and still miss-adjusted....There is a certain waveform in the oscillator that is supposed to be tweaked such that the point is at the same height as the hump on the other side of the valley between them when viewed on an oscilloscope.

Has the horizontal section been recapped recently with good parts? What are the cathode, grid and screen voltages on the H output tube, and what does the service literature on it say it should be?

I'm no expert on rewinding, but I'll say this: They chose the thickness and turns ratio of the windings for a reason and changing that without understanding of the design process, unless you absolutely could not obtain the same type of wire, is a risky move. On things like that it is best do it right the first time.

[Retro-guy]

Okay so I probed it with my scope and here are the results,was scoping with the disconnected (G2) feed resistor to the PL504 and I heard the oscillator just a bit,not as loud as If I connected the g2 feed resistor back ...

I also measured the PL504 cathode current at first when it starts up the current is between 190-210 mA then it goes to 220-250 mA and isn't still,it jumps a bit down and up and down,when it reaches nearly 260 mA then red plating starts ...The horizontal frequency coil has a affect on the current but the current just keeps jumping around,the EHT ,both deflection seem to be stable and working fine ...

Voltages : some of them are off ... The g2 feed resistor to PL504 connected !

PL504

1. -37V
2. -36V
5. 54mV
6. 160V
7. 160V
8. 0.2V
9. 17mV

PCF802

1. 213V
2. -0.8V
3. 97V
6. 150V
7. 11.22V
8. 13V
9. 8.5V

PCL805

1. 300V
2. 230V
3. 250V
6. 258V
7. 250V
8. 32V
9. 11.6V

What would cause the cathode current to jump around like that and not be stable ?
The 500K potentiometer in pic was burnt a bit ,but when I tested it tested GOOD ..
Then I replaced the VDR resistor and it seems to be fine now ...

This TV is beginning to be a real pain in the ass ...

[Retro-guy]

Okay so I finally got a decent picture on it, after re-rewounding the flyback with correct thick wire and replacing the High Voltage winding as seen in pictures.The new HV winding measures about 130 ohm, if that maybe tells how much kV it produces, it should be 18kV, but I have a felling its a bit higher then that.

but now that I replaced the HV winding I'm thinking the high voltage might be a bit excessive which can cause x-ray radiation, is that possible ?

I used the winding from a flyback out of a 80s color TV which used a tripler.I need to get a high voltage probe to be sure, but it definitely is a bit high because brightness is very limited.Is there a way to lower the HIGH VOLTAGE somehow without to much complications ??

there is also a problem with bars appearing when there is a bright white dot or face(look at picture 3) what could be causing that ?

but overall not to shabby !

[Electronic M]

IIRC X-rays form around 25KV, and tend to be fairly weak....Unless you stand closer than ~2 feet from it for a looong time you probably are not getting hit with a dangerous or even measurable amount X-rays.

The bars are likely a symptom of the set's designers not adding DC restoration to the video chain....There are period articles on how to add DC restoration you may want to look for.

It looks like your set has got case of the cone heads... The height and vert lin controls could probably use a touch up.

On the HV there are a few solutions. A roughly 3KV IIRC pF rated cap (or change in the cap's value) across the damper tube will change width and HV, reduction of HV winding turns will reduce HV, a resistive voltage divider may be possible with HV rated resistors, it may be possible to load it down with resistors or something like a 6BK4 HV regulator tube, but that could strain the flyback if it draws too much power.
GET an HV PROBE before trying any of this! You need to know how close you are to spec before tweaking! If the HV is within 4KV of spec you are probably best off leaving well enough alone.