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Electronics => Repair => Topic started by: NickyYTSRB on July 23, 2019, 09:23:15 pm

Title: Lexmark E260 usb data lines shorted to ground
Post by: NickyYTSRB on July 23, 2019, 09:23:15 pm
My printer is not getting recognized via usb and i decided to measure continuity between d+ and d- and both are shorted to ground. There is capacitor parallel to ground pn both d+ and d- and after that series resistor that leads to main soc. Data lines coming from the soc are shorted to ground. If the resistors and capacitors on data lines are faulty what is the chance of soc being okay with data lines. Soc boots normally and diagnostic paper prints when requested. Is ltp worth using in 2k19? Can i still get printer info and set toner thickness and etc via ltp same as via usb? Im still a 18yo kiddo and i have no idea if that printer to pc communication via ltp can transfer such data about paper jam and etc... I will tru to desolder resistors and capacitors to get data lines from soc floating and measure it again.
Title: Re: Lexmark E260 usb data lines shorted to ground
Post by: KD4CCF on July 24, 2019, 04:26:11 am
If you're in the US, you can get a refurb 90 day warranty unit for $110 shipped to your door. Has network connectivity too.

(no affiliation)
https://www.ebay.com/itm/333263311168 (https://www.ebay.com/itm/333263311168)





Title: Re: Lexmark E260 usb data lines shorted to ground
Post by: Chriss on July 24, 2019, 05:49:45 am
Hi!
Most of time there is sitting somewhere near the usb connector prptective diodes and esd protective IC which is also some type of diodes.

I relaired many times this kind of problems on usb devices.

First make the D- and D+ lines clean grom any protection parts and then check if it is inshort.



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Title: Re: Lexmark E260 usb data lines shorted to ground
Post by: NickyYTSRB on July 24, 2019, 10:23:27 pm
Well guys sadly it's shorted inside soc. I hope that parallel port still works. Removed capacitora and resistors and no change.
Title: Re: Lexmark E260 usb data lines shorted to ground
Post by: Chriss on July 25, 2019, 06:33:27 am
Can you please post a picture about the region on the pcb where the problem exist?

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