HP Photosmart 7520 - Power Switch Not Working & power on indication LED not illuminated

[golden79]

The power switch on my HP Photosmart 7520 is not working. It appears that the switch failed in the "on" mode. The printer is always on and I cannot turn the printer off with the power switch. Also, the first indiation of this failure was when I noticed the white led on the power switch was not illuminated or on, but the printer was on and the printer responds to the touch screen. The power switch does not respond to anything such as depressing the power switch for extended periods of time. The only way to turn the printer off is to pull the plug to the electrical outlet or the power cable from the back of the printer.

I've attempted to resolve this failed power switch problem by various printer reset procedures. All resulted in no success.

It would be very helpful if HP would provide access to a service manual or repair manual for this printer. The user manual is not helpful. Also, I'm looking for printer full dissesmbly instructions. I suspect there may be a bad electrical switch or fault on the power board. From experience, I've learned that HP printers can be very difficult to disassemble if proper instructions are not available.

Does anyone have a solution for this HP e-All-in-One-Series printer power switch failure?

Regards

[golden79 · Accepted solution]

The source of the problem has been identified. The smaller of the two flexible flat ribbon cables that connects to the control panel display has at least one of the six conductors with a break. The six conductor ribbon cable that appears to connect the control panel display with the On/Off power switch needs to be replaced. I was able to get the power on LED to illuminate by flexing this cable. A careful examination of the cable end reveals at least one broken conductor. Of course this part is unavailble from HP. This cable is easil sourced from several Asian sellers on eBay. This flat flexible ribbon cable is commonly referred to as "power button ribbon cable." The specs are printed on the 6-pin or 6-conductor cable:  hf E248682 AWM 2896 80C 30V VW-1.