Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: Deathadderpt on May 26, 2009, 12:17:54 pm
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Hi guys
I have a problem with an HANTAREX POLO STAR 28. When i turn the monitor on a transistor keep blowing up. when this happens i star to hear a click every second. I already change the line transformer and it continues to blew. I give a photo of an chassis similar to mine and the transistor is mark with a red line. Its on the right side. If anyone can help me.
(http://img37.imageshack.us/img37/2081/polostar.jpg)
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i had this happen a few times,the first time my replacement phillips transistors were part of a bad batch(bu2527) and the second time there was a few electrolitics in the psu section causing the transistor to blow
there is also a high voltage cap on the collector of the hot which will do the same
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if ur frequently losing the hot , check for cold solder joints on ALL flyback pins, driver xformer, deflection circuitry .
also check for excessive B+ voltage
there is usually a 'lytic bypass cap (1-10uF/160-250v) on the b+ side on the driver xformer.
when this cap degrades, the drive waveform becomes distorted .
this distortion affects the duty cycle of the horiz output xistor (hot). typical pulsewidth 12.6 us @ 15.750 khz
as the xistor stays on longer over time, eventually stress will cause the xistor to short.
qrz