Television 1960s 23" Weltblick 511TR

[Retro-guy]

I just picked up this set as you can see from the pictures its in mint condition,very low hour,I only went for its cause of its nice wood finish,but when I got to it,I saw in what great condition it actually was.The
seller told me it was pretty much put out use as new,maybe cause the flyback failed on it and they never fixed it.It comes from Austria which means its a European set .When I went there to get it
the guy even had the original box in which this TV was bought new .

When I got it there was no raster only sound,so after further investigation I found out that the flybacks secondary winding had a short winding.

After rewiring and re-wounding it the set came alive but I wasn't ab-lee to adjust contrast and brightness,but the picture tube is very bright and seems healthy,which would make sense if its very low hour ...

After further testing I found a open winding on the secondary winding of the flyback,but more deeper inside then the shorted one ,open winding doesn't show on scope ring test,if it were a short then I would find it earlier .... The open winding is used in the voltage supply circuitry that goes to the grids of the picture tube (which could explain the brightness and contrast problem ...

So I had to rewound the flybacks secondary windings AGAIN (the non high voltage ones )
Now we will see if the problem goes away ...


Also what is the most simple way to inject signal/video in this thing ? I tried a vcr but didn't get anything ?? gonna try a different VCR later ...

[Tom Albrecht]

Beautiful set with that nice wood. I also like the way the European sets have the CRT glass bulging out the front a bit and minimal or no mask around the CRT face. Now that you've rewound two different windings on the flyback, is it closer to working properly?

[Retro-guy]

Well after rewinding it (also used better quality wire,with better insulation) and removing the short I got the results(see pic) but I wasn't ab-lee to adjust the contrast or brightness or very limited,the sound tuners worked okay

But then later I found a open winding that supply a voltage to one of the grids of the crt,so I had to rewound it all again (PAIN IN THE ASS) still in progress .

The pics tell more ... there you can also the the flyback before and after the re-wounding ...

[old_tv_nut]

For your signal input problem, give us some more info:
Is the VCR a European one? Are you trying to use RF or baseband composite?

[Electronic M]

I'm impressed that you were able to rewind the flyback.

I believe that there is a forum section specifically for non-North American region sets that this thread better belongs in.

[Retro-guy]

Okay some update ...

After I fixed the open winding by redoing everything again the problem went away and now I can adjust brightness and contrast no problem,but I still think that like 25 % of high voltage is missing ,cause I get a dim spot in the middle of screen when I turn the brightness up and it even goes out of focus a bit in the middle ...

Also I replaced a very burn resistor that got hot,but checked OK on multimeter,is it possible if a resister gets hot it jumps of the correct value ??,cause when I replaced it
the picture got slightly better ??


I also used a smaller cap for the boost capacitor a 47000 pf INSTEAD of a 56000 pf
can that cause it to have low high voltage ? almost like the voltage supplying the high voltage circuits is low ??

[old_tv_nut]

Originally Posted by Retro-guy

Okay some update ...

...

I also used a smaller cap for the boost capacitor a 47000 pf INSTEAD of a 56000 pf
can that cause it to have low high voltage ? almost like the voltage supplying the high voltage circuits is low ??

If that cap is part of a resonant circuit (not just a filter) it could affect things.

[Edit - I also am impressed you could rewind parts of the flyback.]

[Electronic M]

If that boost cap is on the damper tube, then it's value effects the horizontal width and HV....It was a common trick on American sets to add extra capacitance by putting another capacitor in parallel to increase width when the H sweep tubes were running low on usable life.

[Retro-guy]

Okay I did some searching

I think I have A CONDITION CALLED blooming which causes the raster to expand by 10 % if I turn the brightness up,loses focus in middle to,which it does and is caused by poorly regulated EHT ??

Also when I clunk thru the channels the dim spot goes away and the tube is flashing very bright so I know its a good tube,which means either poorly regulated EHT,B+ maybe...someone mentioned to me that
the B+ that goes to vertical deflection,that the fault might be there ??

Which means if poor regulated EHT ,would cause the tube to not operate at its fullest and I could have a much brighter tube if the things driving it would work properly :d

Originally Posted by Electronic M

If that boost cap is on the damper tube, then it's value effects the horizontal width and HV....It was a common trick on American sets to add extra capacitance by putting another capacitor in parallel to increase width when the H sweep tubes were running low on usable life.

I just tried it with a 68.000 pf cap which is more then enough in the place of the 56.000 pf but results are pretty much same ...

[wa2ise]

Originally Posted by old_tv_nut

[Edit - I also am impressed you could rewind parts of the flyback.]

How did you know how many turns of wire for each winding? I suppose one way is to keep count as you undo the old windings.

Coils usually used a criss cross winding pattern, the wires taking a pattern of \ and / as they go round the circumference of the winding. Hard to do by hand. This pattern is to reduce winding to winding capacitance.

You're lucky that the very high voltage winding wasn't atop the other windings.

[Electronic M]

Originally Posted by Retro-guy

Okay I did some searching

I think I have A CONDITION CALLED blooming which causes the raster to expand by 10 % if I turn the brightness up,loses focus in middle to,which it does and is caused by poorly regulated EHT ??

Also when I clunk thru the channels the dim spot goes away and the tube is flashing very bright so I know its a good tube,which means either poorly regulated EHT,B+ maybe...someone mentioned to me that
the B+ that goes to vertical deflection,that the fault might be there ??

Which means if poor regulated EHT ,would cause the tube to not operate at its fullest and I could have a much brighter tube if the things driving it would work properly :d




I just tried it with a 68.000 pf cap which is more then enough in the place of the 56.000 pf but results are pretty much same ...

Most monochrome sets lacked any HV regulation circuitry, And 'HV regulation' (more like HV sag) were usually caused by excessive load on the HV circuit, or the horizontal deflection system being miss-adjusted or having defective parts.

[Retro-guy]

Yea I made a machine that helped me to unwound it and at same time count the turns and length of wire.., very handy


Ive used some kind of special tape for insulation between layers that I got from a guy who re-wounds motors and the flyback seems to be working GOOD ,no shorts/overheating/smoking so the hard part seems to be over

You can see from pics I stripped it completely down ...
But this dim spot and blooming,poorly regulated EHT is bothering me quite HARD

Originally Posted by Electronic M

Most monochrome sets lacked any HV regulation circuitry, And 'HV regulation' (more like HV sag) were usually caused by excessive load on the HV circuit, or the horizontal deflection system being miss-adjusted or having defective parts.

well maybe just a little but IF I turn the brightness close to max the dim spot gets even more visible and the focus goes away(raster stretches for about 10%),gonna take some voltages tomorrow and put a signal into it
and then well see where we are ...

[old_coot88]

Have you substituted the HV (EHT) rectifier tube? It is the most frequent cause of blooming.

Even if it tests 'good' on a tester, it can still fail in operation. The only valid test is subbing with a known good tube.

[Retro-guy]

Originally Posted by old_coot88

Have you substituted the HV (EHT) rectifier tube? It is the most frequent cause of blooming.

Even if it tests 'good' on a tester, it can still fail in operation. The only valid test is subbing with a known good tube.

Well at this moment I don't have a spare one but the DY87 in the set seems to be OK ALMOST LOOKS LIKE NEW ...


it probably has bad EHT regulation,what components can I check ???
Also where can I found some lecture on how these things work,so I would know a bit more what I'm doing ??

[Electronic M]

Originally Posted by Retro-guy

Well at this moment I don't have a spare one but the DY87 in the set seems to be OK ALMOST LOOKS LIKE NEW ...


it probably has bad EHT regulation,what components can I check ???
Also where can I found some lecture on how these things work,so I would know a bit more what I'm doing ??

A tube can LOOK PERFECT and BE COMPLETELY DEAD....However if it looks dead (white getter, hole or crack in the glass, etc) it is dead. The only sure test of an HV rectifier is to get another HV rectifier and try it in the set. No tube tester made comes close to testing HV rectifiers under real world application conditions.

Also there is almost certainly NO HV regulation circuit in that set. Usually they design the horizontal deflection system, flyback, and HV rectifier system to produce varying, but acceptably varying HV output. However if the HV/horizontal deflection system is loaded beyond design (as I suspect yours is on the edge of, since increasing the brightness pushes it over the edge), or the oscillator/output is not preforming correctly it will vary outside the acceptable range.

There have not been lectures on this subject in decades. You can find some TV troubleshooting videos on youtube (Banderson has many good videos) which may be helpful, but you are best off getting some TV servicing books off the internet, and reading them. Also google searching this forrum and others like it will dig up some good info on horizontal troubleshooting. Unless you can find someone with the same set and issue the info will be general, and possibly not completely apply to your set.