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Looking for replacement for SK8085 IC

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deejay2k1

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has anyone used this ic? originally it was made by Unitrode, but they merged with TI, and nobody knows a replacement for it. It seems to be more likely a 3842, but with internal Rt/Ct ....
 

sk-8085

i've done some research, burned a few, but i finally manage to replace sk8085 with uuc3842.

here it goes:

swap pin 1 and 2 (comp and feedback)

mount 100k resistor between 1 and 2

remove capacitor between gnd and pin 4

mount RC network between 4 (ref out), 8 (RC), and gnd (eg. 10k from pin 8 to pin 4, 4.7 nF between pin 4 and GND)

Good luck .... please notify in case of problems

dragos_mb@yahoo.com
 
Re: sk 8085

hello;
thank you very much for sharing your experience.
i replaced sk-8085 as per your instruction and it worked, but now i am facing a problem, when i turn on the power, output starts blinking and sound like click.. click.. and when i puts some load at this condition , then output stops clicking and holds and produces constant output but generated whistling sounds.
please suggest what should i do now?

i am attaching the behavour of power supply
YouTube - 01032011005

thank you for your cooperation
Best Regards
mkk
 

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