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Title: Tatung VS14428 still chirping need dynamite Post by: badbaud on December 17, 2010, 11:49:57 PM What the heck!
If I disconnect the 86-116V line, or the 20-27V line, or the 12V line the power supply stops chirping and all 3 voltages are present (no load on the disconnected output of course). I have replaced all electrolytic caps in the power supply section. the TDA4605, The main MOSFET, pulled each resistor out of the board and measured it for proper resistance, removed each small cap from the circuit and checked them with a cap meter for accuracy, re-soldered all diode leads and the power supply still chirps when all 3 power supply outputs are connected. I can see one of the outputs having some kind of short and causing the chirp but this problem doesn't fit that scenario. It doesn't chirp if I disconnect one of the three outputs. I also changed the vert amp, the LA7851, and Q808, and Q807 and their burned base resistors. Indicates a 12V problem but the 12V is solid if any other output is disconnected. Where do i go from here to fix this problem? Title: Re: Tatung VS14428 still chirping need dynamite Post by: Ken Layton on January 08, 2011, 02:21:55 AM Contact the tech support at the manufacturer:
http://www.tatungusa.com/eng/product_support.aspx (http://www.tatungusa.com/eng/product_support.aspx) Title: Re: Tatung VS14428 still chirping need dynamite Post by: badbaud on January 08, 2011, 02:49:15 PM Found that the low voltage transistors and their base resistors had somehow burned up due to a bad FBT.
Took a FBT out of a known good monitor and tried it in this "chirper" and it came right up. Now seeking a FBT for the unit I stole from. |