Riddled TV Repair Forum

mlloyd1 · Joined: 25 May 2008 Posts: 3

i've got a KV2093R (this is a 20+ years old set) that won't turn on.
checked the obvious: power fuses, they all look good.
now, i suspect the horizontal output transistor 2SD1555.
got to discharge the crt before i poke at that, so i thought i'd take a moment to ask if anyone has seen anything similar.

edit:
forgot to mention no front LEDs come on, so i should probably add voltage regulator to the parts to check. regulator is STR3035.

thanks,
mlloyd1

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kuhurdler · Joined: 28 Dec 2006 Posts: 2582 Location: Overland Park, KS

replace the HOT if you suspect it. They are quite cheap compared to many other parts.

here is one for 3 bucks:
http://www.mcmelectronics.com/product.aspx?productid=2SD1555

mlloyd1 · Joined: 25 May 2008 Posts: 3

thanks, you're right. :-)
just hoping to catch anything else that might as well be checked/replaced while i have it opened. i'd hate to replace the hot and have it die again. i'm fixing the set for my daughter to use until she buys what she really wants.

Jesse Mack · Joined: 22 May 2008 Posts: 600 Location: The Last Frontier

If you have a meter, check the resistance between the center leg and the other two legs. The resistance should be in the high K-ohm range. If the resistance is very low, like 0~5 Ohms the transistor is possibly shorted. It is normal to have very low resistance between the legs that are the farthest apart. Unsolder the center leg and measure the foil to ground. If the short is gone the transistor is shorted. If the short is not gone the Damper diode is most likely shorted. If it turns out that the HOT is shorted, do not forget to resolder the driver transformer. A bad connection on this transformer is usually what causes the HOT to fail. This transformer, if I remember correctly, is a quite small, 1/2 ~ 3/4 inch square, and the windings are usually covered with either black or red plastic.

Jesse

mlloyd1 · Joined: 25 May 2008 Posts: 3

jesse:

thanks for your advice. i've ordered a couple of hots; mine measured bad.

mlloyd1

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