GET1949: ENVY 7640 whistling noise

[E-roq]

http://h30434.www3.hp.com/t5/Printer-All-in-One-Install-Setup/Envy-7640-whistling-noise/m-p/5198385#...

Envy 7640 whistling noise - HP Support Forum - 5198385

Product Name: Envy 7640

The Envy 7640 "whistling noise" appears to be on ongoing problem and seems, as yet, to be unresolved and not limited to just one country. My Envy 7640 printer is a couple of months old and hs exhibited the noise problem since installation. Very irritating in a home environment.

Here's what I did to investigate the source of the noise:

1. Unplug the mains cable from the rear of the printer.

2. Remove the single Torx screw (a flat screwdriver blade will also fit) above the mains inlet socket and indicator LED.

3. Remove the small panel to reveal the sealed power supply block (PSU).

4. Remove the 3 pin DC connector at the top of the PSU and it should simply lift out.

I then plugged in the mains cable to now disconnected PSU and noted that, off-load,  it emitted a load buzzing noise at approximately twice the mains frequency (that's 2 x 50Hz + 100Hz in the UK).

Following this, I disconnected the mains cable from the PSU and reconnected the DC cable - taking care not to strain this as there's not a great deal of slack. I then reconnected the mains cable and immediately noted that the PSU block emitted the, by now, very familiar whistling noise - clearly the PSU is the source of the problem.

As an ex-electronics engineer with a long experience of switch mode PSUs, the noise problem is clearly one of insufficient damping on the ferrite components in the PSU. Most PSU manufacturers use a hot gluetype product or conformal coating to minimise audible harmonics on these components but, without breaking apart the casing, it's obviously not possible to visually inspect the circuit board to check that this is the cause of the noise problem.

For info; the PSU from my printer is a HP Part No. A9T80-60008 and the Serial No. is 141111XXC4A4.

Whether there is a major design flaw in the PSU product or, if there's simply a bad batch is difficult to say but, from a customer perspective this is clearly a major issue that mars an otherwise excellent all-in-one printer. Clearly, I don't really want a replacement printer from the supplier as, from the forum, this doesn't seem to solve the problem. Possibly a replacement PSU might resolve the issue but, only if the PSU design has been amended.

HP should clearly address the issue globally and, in my case, solve the noise problem for me before it drives me, the wife, the dog and the cat crazy.

[#2]

The Envy 7640 "whistling noise" appears to be on ongoing problem and seems, as yet, to be unresolved and not limited to just one country. My Envy 7640 printer is a couple of months old and hs exhibited the noise problem since installation. Very irritating in a home environment.

Here's what I did to investigate the source of the noise:

1. Unplug the mains cable from the rear of the printer.

2. Remove the single Torx screw (a flat screwdriver blade will also fit) above the mains inlet socket and indicator LED.

3. Remove the small panel to reveal the sealed power supply block (PSU).

4. Remove the 3 pin DC connector at the top of the PSU and it should simply lift out.

I then plugged in the mains cable to now disconnected PSU and noted that, off-load,  it emitted a load buzzing noise at approximately twice the mains frequency (that's 2 x 50Hz + 100Hz in the UK).

Following this, I disconnected the mains cable from the PSU and reconnected the DC cable - taking care not to strain this as there's not a great deal of slack. I then reconnected the mains cable and immediately noted that the PSU block emitted the, by now, very familiar whistling noise - clearly the PSU is the source of the problem.

As an ex-electronics engineer with a long experience of switch mode PSUs, the noise problem is clearly one of insufficient damping on the ferrite components in the PSU. Most PSU manufacturers use a hot gluetype product or conformal coating to minimise audible harmonics on these components but, without breaking apart the casing, it's obviously not possible to visually inspect the circuit board to check that this is the cause of the noise problem.

For info; the PSU from my printer is a HP Part No. A9T80-60008 and the Serial No. is 141111XXC4A4.

Whether there is a major design flaw in the PSU product or, if there's simply a bad batch is difficult to say but, from a customer perspective this is clearly a major issue that mars an otherwise excellent all-in-one printer. Clearly, I don't really want a replacement printer from the supplier as, from the forum, this doesn't seem to solve the problem. Possibly a replacement PSU might resolve the issue but, only if the PSU design has been amended.

HP should clearly address the issue globally and, in my case, solve the noise problem for me before it drives me, the wife, the dog and the cat crazy.

[JeffHelp]

08/17/15 - Jeff reached out to customer