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Author Topic: Geometry issue - Hantarex Polo/2 28'' 15-25kHz  (Read 851 times)

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mata

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Geometry issue - Hantarex Polo/2 28'' 15-25kHz
« on: January 06, 2025, 07:49:21 am »
Hi everyone,

trying to restore a Polo/2 28''. Have some horizontal geometry issues. Picture attached below.

I've so far done the following:
- Checked B+ which is fine
- Played with the controls board to adjust Hamp, Hpos, Pincushion, but no luck (can't even increase the picture horizontally)
- Replaced the E/W board
- Replaced all electrolytic caps
- Replaced HOT

Any ideas what might be causing the problem? I am guessing that it should be something around either E/W board or Horizontal deflection.

Thanks,
Martin

princess prin prin

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Re: Geometry issue - Hantarex Polo/2 28'' 15-25kHz
« Reply #1 on: January 06, 2025, 10:03:25 am »
This is a pincushion distortion with narrow picture which means the correction signal doesn't get to the diode modulator. This can be caused by a number of reasons. Measure resistance from the middle pin of T19 (BDX53A attached with a spring to the big heat sink) to the cathode of D47. You want to have very low ohm here, almost continuity. If you have high ohm and R135 is a resistor (and not a jumper), it's probably open. Other possible causes: bad IC3, T18, T19. Check continuity from pin 8 of east-west module to pin 6 of IC3. Check power to IC3.
« Last Edit: January 06, 2025, 10:07:11 am by princess prin prin »