Originally Posted by SeventhHeaven
Good God man! That thing is nasty inside! If I was you, Id just clean it all out. It looks like whoever had it before you, was listening to music in a friggin ourdoor cave!
I cant see any way around cleaning it other then, elbow grease and patience....
Yeah it was full of dust. I did only pay $400 + shipping for the 7550HD which seemed a bargain for this + remote. I already have an HK mic. from another receiver. The outside of this thing is near-mint. I have to look extremely hard to find a blemish on it.
I finally got around to cleaning this unit of dust, replacing OEM fans, and adding two additional fans. This has taken some trial and error on my part, as I initially purchased the wrong fans. I had purchased 5V fans when I needed 12V. I also tried a 92mm Noctua fan as a replacement for the OEM 92mm fan, but it just didn’t move enough air due to it being a low noise fan and the unit would shut down after about 30min.
I replaced the 30mm fan with a cheap fan from amazon. It is somewhat quieter, but not quite as quiet as I’d hoped. I had thought about cutting into the side of the case to expose more of the fan (as shown earlier in this thread), but whether the case is on or off doesn’t seem to matter in regard to fan noise from what I could tell. I was really hoping to fit a 40mm fan in place of it, but not possible without modifying the chassis. I’m going have to cut into the HK’s chassis support to fit a 40mm fan. That will be my next mod.
The front fan was replaced by a 92MM Antec fan, along with a 92mm fan filter. This is the only intake fan on the entire unit, and after all of the dust I recently cleaned from the unit, the addition of a filter seemed warranted. I then added an 80mm exhaust fan on top of the tunnel. The one I used is from AC Infinity on Amazon and fits perfectly snug between the top rails of the tunnel and still leaves clearance for the 7550HD case. It is powered by a USB charger which is plugged into the back of the 120VAC switched power outlet on the HK. I also added a 2nd 80mm fan at the back of the tunnel to assist with moving air out of the unit. I used the Noctua anti vibration mounts (push in) to secure the fan to the back of the tunnel. This fan is also powered by the USB adapter mentioned previously.
In order to get the usb cable from the 80mm fan on top of the tunnel to the usb adapter at the outside rear of the unit, I had to cut and splice the wire, and run it from the inside of the chassis to the outside. There was no way to run the cable out of the back of the unit without drilling a small hole, which I did not want to do. Luckily, there is a raised standoff on the underside of the case, which allows enough room to run a cable underneath the unit and out to the back. I secured the cable tightly to the underside of the chassis.. Not as clean of an install as I would have liked, but you will never see it and it can be removed easily if needed.
The AC Infinity fans are awesome because they include inline 3-speed controllers. I have both set on low. You can see that I cut and spliced the usb cables to remove them of any excess length. I then mounted the fan speed controllers on each side of the rear fan using velcro, so that they can be accessed if needed, but still unobtrusive and out of sight within a cabinet.
The unit with the replacement fans and additional fans runs much quieter than it did before. Even with the USB fans on low makes a significant improvement to cooling the unit and keeping the front temp-controlled fan at minimal noise. I am pretty pleased with the results from efforts to reduce noise, and hopefully I’ll get some years of enjoyment out of this receiver. Even after several hours of use at moderate volume levels, this thing barely gets warm on the outside.
One thing I did notice inside the HK is that there are additional 2-wire header connections for powering other components. It may be possible to power additional fans from there, though I did not check voltages to support this idea.
I’ve attached some pics of the added fan and wiring. I think I cleaned it up nicely. Will post back with pics of my 40mm fan mod once it's completed (if it’s successful).