UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

mole42uk · 26th Jul 2018, 8:45 pm

I wonder if anyone can help with this bit. I might be having a mental block, but I can't see how the circuit works.

Given that the 3524 shutdown pin is active low, how does the circuit around Q10 work? It is supposed to shut the PWM down if there's an overvoltage output. D16 feeds the 12V start-up votage to pin 10, and R41 holds it low unless something else holds it high.

But how does the circuit arount Q10 act as an over-voltage shutdown?

26th Jul 2018, 8:45 pm	#6
mole42uk Nonode Join Date: Aug 2010 Location: Resolven, Wales; and Bristol, England Posts: 2,608	Re: Gould 4072 bad PSU I wonder if anyone can help with this bit. I might be having a mental block, but I can't see how the circuit works. Given that the 3524 shutdown pin is active low, how does the circuit around Q10 work? It is supposed to shut the PWM down if there's an overvoltage output. D16 feeds the 12V start-up votage to pin 10, and R41 holds it low unless something else holds it high. But how does the circuit arount Q10 act as an over-voltage shutdown? Attached Thumbnails __________________ Richard Index: recursive loop: see recursive loop