On Friday 06 December 2002 07:58, you wrote: > Hello. To put this as simply as possible, I got given an old olivetti pg306 > laser printer which fired up ok a few times but then suddenly stoped > working, ie no hum, no lights, no nothing. I remember startup was a bit > dodgy, somtimes it would turn on, other times nothing, but now only > nothing. I've replaced a few parts in the power supply that I thought might > have been at fault using parts from a smashed up identical printer, infact > i found a 0.5w resistor which had no reading upon measurement, it was > supposed to be 220 ohm but the same resistor in the smashed up printer > showed a yellow band instead of brown (220Kohm), I tried fitting a new 220k > and then 220ohm with no luck, this resistor was acting as a voltage divider > with a 220k resistor at the base of a transistor which i also replaced. > I still have no idea whats gone wrong, I haven't much knowledge of switch > mode power supplies or analog electronics as a whole and was wondering if > anyone might have any suggestions... > Thanks very much for listening > Quite a common construction involves the mains being rectified at the input, and a high value low wattage resistor (220K - 1M5) and low voltage zener providing a startup power supply. This high value resistor is probably a lot higher, or open circuit. Use a bigger wattage next time. Don't ask - just put in a higher wattage. -- Regards,
Declan Moriarty. -- Author: Declan Moriarty INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
