Hantarex Polo 20 image problem

baritonomarc

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Hi all,

I have just bought a working (O_O) 20' Hantarex Polo... not working.

Essentially the image is present only in the upper part of the screen (let say 10-20% from the top of the monitor) and spread outside down to the bottom of the screen (see attached images).

The problem IS 100% NOT the video signal or the harness because i tested everithing with another (working for real) Polo.

Consider that the monitor has only few hours of work (the Fly area is not browned, nor any other high temperature zones)

Thanks!!
 

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The problem IS 100% NOT the video signal or the harness because i tested everithing with another (working for real) Polo.

Something about that part stuck out to me... ... I've never heard of such a thing.

Just a bump I guess, no real advice as I stay as far away from Polo's as possible.
 
Something about that part stuck out to me... ... I've never heard of such a thing.

:)

joking apart, Polo's are great monitors when they are ok. I have never seen images better than those (crisp and clear), and i can say that i have seen almost every (common) arcade monitor in action.

Hewitson, shotgunning the caps of the vertical deflection circuit you mean?

Notice that the image is correct only in a very limited range and stretched in the lower part AND in the upper part

Any other idea?
 
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Ok, made some progress today. I turned the vertical linearity pot RV102 full clockwise and anti-clockwise: the image spread changed, but i could not regroup the full image on the screen area.

At this point i suppose that all the resistances on the vertical deflection circuit need some check
 
Let me check my notes because i just had the same thing going on with a Polo 33". I had to replace a diode and a resistor going to one of the IC's. I'll check.....
 
Let me check my notes because i just had the same thing going on with a Polo 33". I had to replace a diode and a resistor going to one of the IC's. I'll check.....

Thanks, i will wait for your log :)

just to add another test result: i tested the tube with another chassis i have and the image is ok, so it's not the tube (or joke), but definitely the chassis.
 
Still sorting thru my notes at home but, I do have the schematic on my phone and looking at it I remember a few key points-
Near IC103 (TDA1675) check the following:
R166 (2k2) - someone had replaced this with a 4.8k on my board
C139 (1000uf 35V)
C137 (220uf 35V)
R167 (2R7 flameproof)
D127 (BA159)
What's your voltage at TP31 (this is one side of R167)? Should be right around 25Vdc.

I had several things wrong with my board so I replaced several items.
Capkit, ic103, ic104, rgb amp on the neckboard, all the pots on the remote board, and a handful of diodes and resistors. Not all of the components were bad but, i just wanted to replace them for my own personal reasons.

Definitely check the pots on your remote board. And the cable that connects it. Of course i'm assuming that my monitor is somewhat similar to yours LOL!
Hope this helps!
 
Solved !!

Well, i checked all mentioned by bonecollektor and Ohmerone (i ask for his help by pm) and i solved!

Checked all the components next to the vertical IC but, being the monitor almost new, they where not defective, as expected. Reasonibly assuming that the IC was ok, the following "aspirant" where the soldering ... i had at least 5 cold solders at the IC pins!

I am still asking myself how could the seller report to me that that monitor was 100% working the day before...
 
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