Ground lift adapter

[garlandb]

I'm reading conflicting information in regards to the safety of using a ground lift adapter (ie converts a three prong to a two prong) to resolve a ground loop between an LCD monitor and a laptop.

Anyone care to weigh in on this?

 

[mikeford]

Ground loop implies in one or both of those AC circuits you have a bad or weak ground connection, which should be fixed.

From a safety standpoint use or not of a ground lifting adapter on ONE of the devices is less critical.

 

[enwar3]

Ground loop implies in one or both of those AC circuits you have a bad or weak ground connection, which should be fixed.

From a safety standpoint use or not of a ground lifting adapter on ONE of the devices is less critical.

I am having the same problem. I've tried plugging both the monitor and the laptop into the same power strip and still have the same problem. I suspect it is a grounding loop because I experience no flickering when I'm running my laptop off battery.

When you say one of those AC circuits have a bad or weak ground connection, do you mean that the actual wiring in the wall is faulty?

Is there a safer solution (read something about an isolation transformer)?

 

[Mark R]

A ground loop occurs when two items of equipment, which need to communicate, are plugged into different circuits with different ground potentials.

If the two items are plugged into the same power strip - then by definition, they are at the same ground potential, and therefore the problem cannot be a ground loop.

 

[Rubycon]

It's possible if there is a differential between circuit ground and chassis ground though. (it should NOT be there though)

Also flip prongs are for test purposes. NEVER defeat the ground on a long term or permanent basis! If insulation fails or otherwise an energized part comes in contact with the chassis (which is now floating because of a lacking ground!) a very hazardous condition exists! If you touch a "hot" chassis and are grounded yourself you can be killed from excessive current flow.

Normally when this happens (with a ground in place) it creates a fault and the branch circuit breaker/fuse opens immediately.

A ground loop occurs when two items of equipment, which need to communicate, are plugged into different circuits with different ground potentials.

If the two items are plugged into the same power strip - then by definition, they are at the same ground potential, and therefore the problem cannot be a ground loop.

 

[enwar3]

A ground loop occurs when two items of equipment, which need to communicate, are plugged into different circuits with different ground potentials.

If the two items are plugged into the same power strip - then by definition, they are at the same ground potential, and therefore the problem cannot be a ground loop.

Ah ok. Well when both my laptop and my monitor are plugged into the same power strip, my monitor flickers. This doesn't happen when laptop is unplugged (and running on battery). If it's not a ground loop, what could it be?

 

[Rubycon]

That could be noise from switching power supplies.

 

[enwar3]

That could be noise from switching power supplies.

The flickering is continuous though, not just immediately after plugging in.

 

[enwar3]

On another note, I'm wondering if I should buy a higher quality vga cable. Both the laptop and the monitor should be at the same ground so I don't know what to do..

I could also buy a 2-prong power cord/adapter from my laptop manufacturer. Which is the better choice?

 

[Rubycon]

What resolution and refresh rate are you running? Only at higher resolution/refresh rates (applies to CRT displays) will bring about limits in cheaper cables unless they are long. If your anomaly resembles a video sync bar it may indeed be RF related in the transmission line. (which is your analog cable btw. )

 

[enwar3]

What resolution and refresh rate are you running? Only at higher resolution/refresh rates (applies to CRT displays) will bring about limits in cheaper cables unless they are long. If your anomaly resembles a video sync bar it may indeed be RF related in the transmission line. (which is your analog cable btw. )

I'm running 1920x1200 @ 60hz on a 28 inch monitor with a VGA cable that's about 6 ft long. I can't change my refresh rate, and I see flickering even at the lowest resolutions. The flickering is very faint, but definitely there (horizontal lines). I appreciate any suggestions you can give me... this is very frustrating =(

 

[Rubycon]

I'm running 1920x1200 @ 60hz on a 28 inch monitor with a VGA cable that's about 6 ft long. I can't change my refresh rate, and I see flickering even at the lowest resolutions. The flickering is very faint, but definitely there (horizontal lines). I appreciate any suggestions you can give me... this is very frustrating =(

DVI not an option?

There are better made cables, however.

 

[enwar3]

DVI not an option?

There are better made cables, however.

DVI's not an option because my laptop is super old =( I'll probably start with a better cable.

 

[Rubycon]

Also some laptop HD15 connectors may not be properly grounded!