...and back on this!
I had this box since 5 years!
![arrow :arrow:](http://www.dragonslairfans.com/smfor/Smileys/default/icon_arrow.gif)
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_1.jpg)
It's time to give a try...
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_2.jpg)
...to this brand new
20" CRT Free Voltage Monitor Chassis Entech 15020 CGA.
I have here two tubes that should be compatible with that chassis, which is basically supposed to work with almost all 20"CRT in arcade CGA monitor tubes :
- HITACHI 510UJB22 :
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_3.jpg)
- ELECTROHOME? / 19VMNP22 / 17-7198-12 :
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_4.jpg)
So I tried that chassis with both tubes, and I got the same issue with both of them, see that picture
![arrow :arrow:](http://www.dragonslairfans.com/smfor/Smileys/default/icon_arrow.gif)
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_5.jpg)
The bottom of the picture is 'stretched', and top is 'compressed' !
![Ghost :ghost:](http://www.dragonslairfans.com/smfor/Smileys/default/smiley_ghost.gif)
... which gives this with a game plugged
![arrow :arrow:](http://www.dragonslairfans.com/smfor/Smileys/default/icon_arrow.gif)
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_6.jpg)
Of course I've tried all the geometry/position/size potentiometers, and none can't remove me that strange problem.
As I said, I've tried that chassis on two different tubes, and got the exact result!
Here's a view of the chassis :
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_7.jpg)
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_8.jpg)
Any idea why this chassis has
TWO rows for the tube deflection connection? I mean one row of 4 pins is enough? What is the purpose of have TWO of them?
![arrow :arrow:](http://www.dragonslairfans.com/smfor/Smileys/default/icon_arrow.gif)
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_9.jpg)
Of course I plugged the tube on both of them, and didn't noticed any difference...
Oh, and what is the purpose of this selector :
![](https://www.dragonslairfans.com/forforum4/entech_crt_chassis_cga_150020_10.jpg)
...it can be set on "W" (factory setting) or "N". What does this mean? I didn't try the "N" position.
Any idea about the whole problem? Could this be because this chassis is built as 20" and I'm using 19" tube? The production description is not totally clear :
Technical Features:
Power Input: 96-240VAC Free Voltage (Power Consumption <60W)
Input Signal: RGB Comp Synch GND (Colours Max 5V P-P) (Synch 2-4V Neg Edge)
Focus: Electrostatic
Convergence: Self Convergence
Deflection Yoke Match: LH - 1.92mH LV - 30mH RH - 2.0 Ohm RV 13.5 Ohm
H Synch: POLARITY 1Vp-p ~ 5Vp-p : FREQUENCY: 15.75 KHZ : PLUSE LENGTH: 3us ~ 7us
V Synch: FREQUENCY: 48HZ ~ 55HZ : PLUSE LENGTH: 190us ~ 500us
Tube size: 48cms/ 20"I guess I should check the deflection yoke tube values. How to to that?