Fidek fan noise fix (1 Viewer)

[Kevin_W]

Since I've noticed Fidek popping up in a couple threads here and the for sale section lately, I thought I would pass this thread along for the benefit of the Fidek users that are concerned about the fan noise. I emailed Mike Knapp to find this little gem and wanted to share the wealth... thanks Mike!
How to quiet the Fidek fan
Zener diode needed
Kevin

 

[JasonWaddington]

I got a 12v 5w zener diode, but there is a problem. This is verrrry strange. I put the diode into the little white thingy where the red wire that comes from the fan plugs in. I then touch the red wire to the diode and the fan starts to go, and slower than before as planned. I then turn the unit off, and start it back up again with the red wire still touching the diode, but the fan doesnt start! it tries to, but doesnt! BUT, get this. If I then take the red wire away and put it back, IT GOES! Then I turn it off while it is going, turn it back on, same story. I tried it MANY times, same result every time. What is the problem???

 

[Rob Rodier]

Wow, that is weird. Sounds like a question for Saurav.

-rob

 

[JasonWaddington]

who is that?

SOMEONE HELP!

 

[JasonWaddington]

seriously guys, someone must have an idea...

 

[EarleD]

Jason,

I just cut the red power wire going to the fan and put it inline with the power wire. Works like a charm. Just plan where you want to mount the heat sink for the diode, so that you cut the wire in the best place.

Earle

 

[JasonWaddington]

Oh, so i cut the wire and then put the diode in with each side touching some of the red wire?

 

[Mark R. Ososkie]

what size is the fan?

why not just replace it with a quieter one?

if any of you can get the fan specs (size, cfm, dba) i'm sure i could reccomend one that is much more efficient.

 

[EarleD]

Mark

To get the fan out is much more work. You have to remove a Circuit board. adding the dioode is much easier.

earle

 

[JasonWaddington]

so, any reason mine shouldnt be working? it is the right part( i checked) and I am plugging the correct end of the diode(withe the white band pointing away from the fan) into the white thingy on the circuit board with the + next to it. the only othet option is to cut the wire in half and put the diode between two pieces of wire. would that make a difference though?

 

[Brian Schucher]

Thats how i did it. My fan starts every time. I dont remember what diode exactky i used but it was the one recommnended by Mike Van Evers. I would need to search the archives of HTT to find out.. Ill get back.

 

[Brian Schucher]

1N5349BMSCT-ND Thats the part number from www.digi-key.com
Thats the one i used and put it inline of the wire itself. I also made a lil heatsink for it too.. Did it in Nov,2000 and still purring along

 

[Brian Schucher]

guess i didnt look at the first post clearly.. All already stated..

 

[JasonWaddington]

Thats the diode I have....Define Inline.....would putting the diode into the white thing count as inline?

 

[EarleD]

inline is cutting the wire and inserting it the diode there. The piggyback thing you are doing may be the casue of the startup problem. I did my mod over 2 months ago and it is running cool even after LOTR at near reference levels.

Earle

Dont wory about cuting the wire if I could do this mod anyone can. Took about 20 min from satrt to finish. Including attaching a heatsind to the case to help cool the diode.

 

[JasonWaddington]

tried cutting the wire, still doesnt work....what could the problem be??? it is the right part and i am doing it the right way....this is so mthrfckng typical.

I am thinking about just disabling the fan and hoping it doesnt overheat. would that be safe? i mean, if its cool with the fan at like 1/4 the speed, it should be fine at nothing....or could i get a slightly stronger diode?like 20v??

 

[Walt N]

Sounds like you're putting too much resistance in the circuit for a reliable fan start. Don't disable the fan completely, you burn up the amp as it has no heat sinks. Forget the diodes, just get some 10w wirewound resistors from Rat Shack like this with different ohm ratings, (100 ohm, 50 ohm, 10 ohm) and experiment with placing them in the fan circuit (doesn't matter which of the two wires) until you find the right one or combination of resistors that will quiet the fan while still allowing a reliable fan start when you turn on the amp. For my Mackie M1400i the 100 ohm resistor worked perfectly, however I don't know for sure what will work well with the Fidek.

 

[JasonWaddington]

By the in the circuit you mean in line with the wire?

And do the resistors need heat sinks?

 

[Walt N]

Yes, in line with the wire. If you need a combo to get it right, for instance a 50 ohm + two 10 ohm resistors for a total of 70 ohms, just twist them end to end and put them in your wire break. Once you find the magic combo which should be the loudest it can be without bothering you in your spot during quiet passages, solder the connections and tape 'em up.

That particular resistor type is a sand-cast design so they need no additional heat sinks. Secure the resistors you end up using to any clear spot on the amp's chassis floor with a little dab of high temp RTV silicone sealant, and you're done. You may need to splice in a bit of extra wire on one or both ends to get the resistor(s) to a clear securing spot.

 

[JasonWaddington]

(i am very bad with electronic components like this, so bear with me)

so a resistor is a functional equivelant to a diode?