Xtant 4180c fan replacement

[chemhaz]

Hi, I just picked up an Xtant 4018c in pretty good condition however the fan needs a little help getting it started. I've sprayed it with electical lube/cleaner and it seems to help but I want to replace it.

The current fan in a 60x60x25mm with a two pin configuration, however I suspect it has been replaced in the past as the amp board has three pins.

Firstly, I need to know, does the amp support a three pin fan ie high and low speed and what the maximum current draw the board can handle is? If it does support the a variable speed fan, what are the pin configurations?

Also the paper that wraps the heat sink to cause a tunnel effect is warped and has gaps in it, thus allowing air to escape, should it be relatively tight, if so what can I use to close the gaps... masking tape, electrical tape or is there a special heat tape?

A friend suggested engine gasket silicon, which I believe is messy and overkill.

Thirdly, does the fan blow air into the heat sink or blow air out the housing.

George

[1moreamp]

It blows air through the entire sink and out the far corner...I have one sitting without a SS cover that needs a home. Works perfect just no cover...

The fan does drive at slower speeds by voltage control, at least it does on mine and its temperature driven. The sensor is located over on the larger sink in a pool of silicone heatsink compound.

As for three pin fans like used in PC's those have the third wire for speed feedback info to the Motherboard. A two pin fan is all that is expected or needed for these amps to my limited knowledge.

I used a piece of rather expensive Kapton tape to rid mine of its buckle in the tunnel cover. The kapton was available and cleaner looking then other options.
You will need a tape with high temperature characteristics to its glue or it will give up the ghost the first time the amp runs hot...just something to think about...With the amp biased properly these sinks get rather hot to the touch, enough to loosen most glues used on typical tapes...

Oh mine has a spare fan I attached on the exhaust end to improve air flow. The spare was donated by a 1K D class amp they made that gave up the ghost.

The fan should be replaced if it fails to start freely at idle turn on of the amp. That will be its slowest drive voltage and if the fan fails to start it may never start later on after the sink heats up.....

Hope these answer were helpful....

[Perry Babin]

From a previous post:
You can repair the fan. Pull the label and remove the retaining ring. Slide the impeller out of the bearing and clean the shaft and bearing with solvent to remove the old lubricant. Put a drop of motor oil on the shaft and/or bearing and reassemble it. It works virtually 100% of the time.



If you want to replace the material on the heatsinks, look for a material called 'fishpaper'. It's a hard fiber material that is relatively rigid. Something ~0.010" thick is probably the best for your purpose.

If you punch/drill the holes in the same pattern as the holes in the original piece, it should work as well as the original shroud.

For the holes, you can use a standard drill bit. Place the fishpaper on top of block of wood when drilling.


Do not remove the clamps on the transistors unless absolutely necessary. All of this work can be done without removing the clamps.