Printer Electrical Grounding malfunction,need advice/help

[abhi@eda]

I have a HP Multi-function Desk-jet Printer 2515 Model,got it 4 weeks back,i experienced current shock at the USB metal pin which goes into my Pc's USB port,the whole Printer is plastic molded,till today i used to plug that USB to my Dekstop and my Laptop,it worked fine,the printer works fine even though the USB pin is malfunctioning..

The Printer power cable has got only 2 pins, No Ground pin,and the power adapter output is 30V at 333mA..

My fear is would this harm or damage my Desktop/laptop if i plug this ungrounded USB Printer cable to my Pc's??? or i can use it without fear??

I also tested the adapter with Multi-meter,and go the correct DC reading of 30V...

as i thought this is related to electrical issue and would like to know what it's effect on PC would be...

Thank you in advance

 

[tpetar]

You can damage USB port on PC or interface in printer, change connector with new is my suggestion.

:wink:

 

[abhi@eda]

but some say the power cable does not have any ground,so its not a major problem, and i am wondering what could be the problem,either the power adapter or the USB cable,any more help would be Great ....

 

[tpetar]

but some say the power cable does not have any ground,so its not a major problem, and i am wondering what could be the problem,either the power adapter or the USB cable,any more help would be Great ....

Why you mention power adapter and ground of printer if USB connector is melted?

Replace melted USB connector with new, and back device to zero state. Change USB cable also.

The real question is why this connector is melted? :wink:

 

[abhi@eda]

Why you mention power adapter and ground of printer if USB connector is melted?

Replace melted USB connector with new, and back device to zero state. Change USB cable also.

i dont remember where i said the USB cable was melted,the USB cable,the printer every thing is fine and working great,but the printer power plug has two pin and no ground pin,so there is no ground for USB and i feel minor electrical shock when i touch it and i am worried if that would harm my PC when i plug it in my Pc's USB port

 

[tpetar]

I'm probably wrongly understand question.

PC and printer are on the same main phase, are they together connected to the same power socket?

 

[abhi@eda]

I have a UPS which is surge protected,from that UPS,i have my Desktop and printer connected, the Printer power cable has only 2 pins and has no ground pin,and i feel a minor shock when i touch the end of USB cable from Printer,i have been using like this for over a month, but is it not a major problem and can be ignored or i should stop connecting the USB to my Pc??

 

[tpetar]

And did you try to touch USB connect when PC and printer are used direct on mains without UPS?

You have some potential difference.

I will try without UPS for start.

 

[abhi@eda]

yes i did,i detached the Printer and plugged it to another wall socket in another room and tested and go same results

its the problem with the printer, but i want to determine if its a major or a minor/ignorable problem... in past i have seen PC's which were running and when i touched,i felt the current through me,even in that case,the PC would run good without any problem,i want to the reason for it

 

[tpetar]

Its voltage potential difference. Specially can give good shock at cable TV cables, VGA cables, old backboned network with BNC connectors,... but when grounding is ok and electronics is isolated from peripheral this is eliminated.



I think, maybe your PC power supply is bad or low quality. If you have another, try it, make small experiment.

 

[abhi@eda]

Sorry,what i had told about having a electrical shock when i touched the USB cable was my mistake, yesterday i felt a shock and tested it with a tester and got the tester's led light up..so i didnt touch it and feel anymore..

But today i touched it again and felt no electrical shock and tested it with tester again and got the tester's LED light up, then i took my Multi-meter and measured the DC voltage from adapter and got a correct reading of 30Volts ,and i took a single positive probe and got around 9 V Ac current, every metal connected to the printer and the USB which is also connected to the printer gave a 9V AC when probed with positive probe of the multi-meter

below is a image of the reading and the way i tested it... please tell me is this is a AC current leak? i cannot feel any shock and the USB works 100% fine with my computer
and would this small current damage the PC?
what could be the reason?

 

[tpetar]

1. Try with other multimeter, I dont trust to this small multimeters.

2. Try with new PC power supply.

3. Can be motherboard USB defect.

 

[abhi@eda]

1. Try with other multimeter, I dont trust to this small multimeters.

2. Try with new PC power supply.

3. Can be motherboard USB defect.

How could it be related to Mother board of my PC ?? the whole Printer mother board has got some AC leaking to it,it has got nothing to do with my PC mother board and definately not a problem with my USB coz its working fine when i print through my computer or maintain the printer with my PC..


I have been using My PC,laptop,Sound system,TV, every socket in my home has got good grounding,there is no grounding issue,i have never felt any shock when i touch my CPU,or any electrical item in my home

the problem is with the printer i think,the printer power plug has only 2 pins and no ground pin,so the transformer in the adapter does not have a ground and it is leaking some AC to the output,so the tester is picking up the AC current,but the AC current which is leaked is less than 9V and it doesn't give any kind of shock,i think a correct value of capacitor would stop the AC entering from the power adapter to the printer... this is my theory on this issue,if i am wrong please do correct me

 

[bobin]

hello abhi

i am also having the same problem and experienced what u have written.

What u have done ?? corrected ?? please reply

with warm regards