Philips 28" A66EAK51X03 yoke help / Compatible chassis (SOLVED)

[perjmolsen]

Hi

Need the experts help and advise again 

I have found this old philips 28" TV.
My plan is to see if I can use this tube as an arcade monitor.

The tube in the TV is a model A66EAK51X03 - If i search online for this monitor I get this result, so maybe it can be used as an arcade monitor. -> https://wiki.arcadeotaku.com/w/File:A66EAK51X03_(2).jpg

I have tried to find the tube information on tubular, I am able to find A66EAK51. -> http://tubular.atomized.org/#s/A66EAK51
It says:
Heater 6.3V
G1: 50V
Neck: CR-23


My issue is that when i measure the yoke windings, there is 5 pins - and I am able to get three readings, so is there three coils?
I need to find out witch one there is the vertical and horizontal - normal the wires are colored from the yoke, but not this time. They are all grey 

My messurements are:
1-5= 6.4 Ohm 8.05 mH
1-4= 3.5 Ohm 1.99 mH
2-3= 2.2 Ohm 1.80 mH

My best guess is that:
Vertical is pin 1-6 = 6.4Ohm and 8.05 mH
Horizontal is pin 2-3 = 2.2 Ohm and 1.80mH

OR???

Does someone know if there is a compatible chassis for this CRT and yoke?

My universal newly fixed china 25"- 29" chassis has the following spec:

VR: 9.6 Ohm 24.6 mH
HR: 1.3 Ohm 1.5 mH

The Ohms is in range, but not the mH - will that be a chassis that I can test the CRT with?

[princess prin prin]

2 - 3 horizontal, 1-5 vertical. The vertical coils are in series and 4 is the common point so 1-4 and 4-5 are identical.

The yoke specs of the chinese chassis are practically the same as the A66ECY13X01 tube on the label I posted in the other thread. This Philips tube, like the Panasonic one, has a vertical coil with a resistance/inductance much lower, similar to the A66EAK552X11 on the label. With these tubes the picture may not fill the screen vertically. To fix this on the Polo chassis the value of R170 which is in series with the vertical size pot needs to be lowered. Whether the chinese chassis can handle the difference or can be modified in a similar way I don't know, you have to try and see yourself.

[perjmolsen]

2 - 3 horizontal, 1-5 vertical. The vertical coils are in series and 4 is the common point so 1-4 and 4-5 are identical.

The yoke specs of the chinese chassis are practically the same as the A66ECY13X01 tube on the label I posted in the other thread. This Philips tube, like the Panasonic one, has a vertical coil with a resistance/inductance much lower, similar to the A66EAK552X11 on the label. With these tubes the picture may not fill the screen vertically. To fix this on the Polo chassis the value of R170 which is in series with the vertical size pot needs to be lowered. Whether the chinese chassis can handle the difference or can be modified in a similar way I don't know, you have to try and see yourself.

Hi

Whau!!!

Again I am deeply amazed about your knowledge 

Thanks for your help with the pins - I have now put on some yoke wires, and put the chassis on my china chassis, and there is picture.   

As you mentioned I am unable to get the vertical size adjusted to the edge, the picture below is with the vertical size pot adjusted fully to the max.
I have tried to move the two jumper wires on the board to the different locations, the way they are connected now gives me the biggest picture.

So if i understand you correct, I might be able to lower the resistance on the resistor that are connected to the vertical size pot?
I guess that i can follow the trace on the bottom, from the vertical size pot to the nearest resistor?

Again  THANKS!

[perjmolsen]

Hi

I have got my vertical size adjusted fine, by using the adjustments on the chassis 

Now I am trying to get the horizontal size to fit.
I have tried to change the resistor (r911) behind the adjustment pot from the original 39k to a 22k that did not change anything - so i put in the original again.

Then i read that the horizontal size is adjusted by lowering the value of the C908 polyester cap.
Original on my chassis it is a 39uf 250V polyester cap.
I have tried to change it to a 22uf  250V ployester cap - then I got the picture wider in size, but it where too wide 

So now I have order a 33uf 250v cap to see if that fits my monitor

[princess prin prin]

You should check the anode voltage when making changes to the horizontal output circuit. Lowering the B+ could be a way to resize the picture.

[perjmolsen]

You should check the anode voltage when making changes to the horizontal output circuit. Lowering the B+ could be a way to resize the picture.

Thanks for the tip 

[perjmolsen]

Hi

An update -

I now managed to dial in the horizontal size also. 

I changed c908 to an 102nf (104J 250V)
Now the picture is perfect on the A66EAK51X03 tube 

Now I will leave it on for a couple of hours to see if anything blows up.
The last fix I am planning to do to my china chassis, is to change the 25W 140 ohm ceramic resistor to a 100W 150 ohm surface mounted resistor, and mount it at the metal on the chassis so the cooling is better.