[Kenwood] TS-940SAT fan help

Tue Nov 7 13:24:13 EST 2006

Avi -
Lubing the sleeve bearing is certainly worth a try, but many of the 940 
fans are 20 years old, and depending upon the hours the unit has may 
have exceeded the life expectancy of the motor. Also, I have seen fans 
that have previously been "lubricated" with ?? or worse, sprayed with 
WD-40, the all purpose bearing destroyer, and are so gummed up they can 
hardly be turned by hand!
Many of the "failed" 940 fans will run from a stiff 12V supply, (we 
don't know for how long,) but draw too much current from what is an 
essentially current limited source. Bottom line is, you DON'T want the 
fan to fail un-noticed in a 940. Normally it's low noise is covered by 
ambient noise and you don't know it's failed until serious damage has 
been done.
73, Garey - K4OAH
Atlanta
Drake 2-B, 4-B & C-Line Service CDs
<www.k4oah.com>
Avi - Modi'im Orchards wrote:
> Why not just lube the bearings on the original fan? every PS or 
> computer fan I've ever had a problem with could be fixed by pulling 
> the sticker off the housing and putting a drop of light oil or turbine 
> oil in there, or if that doesn't give you access to the bearing, pull 
> the blade assembly off the motor shaft and lube it that way. I think 
> you probably have the same fan in your 940 that I have in my PS-50 
> that goes with my TS440, and that's how I (periodically) fix it.
>> -avi 4X6UA
>> ----- Original Message ----- From: "Garey Barrell" <k4oah at mindspring.com>
> To: "joe barkley" <jbarkley at vnet.net>
> Cc: <Kenwood at mailman.qth.net>
> Sent: Tuesday, November 07, 2006 00:00
> Subject: Re: [Kenwood] TS-940SAT fan help
>>>> Joe -
>>>> What's probably happening to your fan is that the voltage is supplied 
>> from the 30V supply through a 820 ohm resistor, and your fan draws 
>> too much current, dropping the voltage too low to start. If you give 
>> it a spin by hand it will probably run. This is a fairly common 
>> failure mode of the Kenwood fan, the bearings get gummed up and the 
>> _start_ current drops the voltage too low to start it.
>> So.... You can either change the resistor on the PS board to a lower 
>> value, or you can do what I did to a 940 when I couldn't find a 
>> replacement fan for less than 30ドル+ from Kenwood. If you put a 22V 
>> zener diode across the resistor, at least 8 volts is supplied to the 
>> fan at startup. Once the fan starts, the current drops enough that 
>> the voltage across the resistor drops below 20V and the zener no 
>> longer conducts.
>> Whatever you do, you DON'T want the fan to NOT come on. The internal 
>> temperature, especially on the PS board, rises enough to damage 
>> several components and cause catastrophic damage.
>>>> The Kenwood fans show up on E* from time to time as the "ship 
>> breakers" are tearing up working units to sell for parts, since like 
>> cars, they bring more money as parts.!
>>>> 73, Garey - K4OAH
>> Atlanta
>>>> Drake 2-B, 4-B & C-Line Service CDs
>> <www.k4oah.com>
>>>>>>>> joe barkley wrote:
>>> I have a very noisey fan on the power supply heat sink.
>>> I have looked for it and put a couple ads out and no luck finding one.
>>> I thought I could ad a 2.5 inch 12v dc fan on the back. I founf one 
>>> and got it hooked up to find
>>> when the thermal switch kicks in the is 18.3 Vdc. The 12V I have 
>>> does not like that and will not operate.
>>> It does fine on 12V. First, does anybody have a fan froma parted out 
>>> 940 and second
>>> how can I get that 18 V down to when this fan will go for it.
>>> Thanks
>>> Joe
>>> KI4TZ
>>>>>