[Yaesu] FT-1000D fan noise

[Jan Erik Holm]

Just to try to help EA3IN I did dig out the schematic.
Personally I don´t object to the fan noise so it hasn´t
been an issue for me .
However:

Fan is controlled from the PS Unit board  page 7-125 in
the service manual.

It looks like it has something like a two step start,
switchtransistors Q7621 and Q7612 seems to control
that.

Also connector J7608 has something connected to it,
could be a thermostat maybe, that controls fan start.
I don´t have time to trace what it´s for right now.

On connector J7607 the fan is connected, Pin 1 is
the "control pin" and Pin 2 is the DC feed.
That is, if you ground pin 1 fan will start, or
if you sink pin 1 in steps towards ground fan will
get stepstart, or put another way run on different
speeds.

To reduce fan noise you want to reduce the overal
fan speed however then the PA transistors will get
less cooling and I don´t know how safe that would be.

Anyway, if you increse the value of resistor R7640
(it´s a 27 ohm 3W) the overal speed of the fan will
be lower. It might be an easy and simple fix.

73 Jim SM2EKM

PS: Maybe connector J7608 controls the "high speed"
possition, if so just pulling it will dissable.
I don´t have time to figure it out right now.
-------------------------------------------------------

Cecil Acuff wrote:
> Yea and get display problems, turn on problems and all the other free 
> options discussed here recently....
> 
> Nah...just keep the 1000D with the fan noise....
> 
> I operate with a good set of headphones so if mine makes noise I don't know 
> it....
> 
> You might be able to pick up a fan motor from Yaesu and change it out....
> 
> Cecil...
> ----- Original Message ----- 
> From: "Bob Maser" <bmaser at tampabay.rr.com>
> To: <yaesu at contesting.com>; "Marcel Jorba" <ea3in at yahoo.com>
> Sent: Tuesday, July 25, 2006 4:59 PM
> Subject: Re: [Yaesu] FT-1000D fan noise
> 
> 
> 
>>Yeah, trade it for a Mark V
>>
>>Bob W6TR
>>----- Original Message ----- 
>>From: "Marcel Jorba" <ea3in at yahoo.com>
>>To: <yaesu at contesting.com>
>>Sent: Tuesday, July 25, 2006 4:15 PM
>>Subject: [Yaesu] FT-1000D fan noise
>>
>>
>>
>>>Hello all,
>>>
>>>I'd like to reduce the fan noise of my FT-1000D.
>>>
>>>It is silent when it starts. I don't know if it is in
>>>a low speed position. After a few seconds
>>>transmission, the fan starts to be noisy. I don't know
>>>if because it starts to blow or because it switches
>>>from a slow to a fast speed position.
>>>
>>>ANy idea to reduce or eliminate the noise. I have seen
>>>some ideas in order to reduce the fan speed or to keep
>>>the radio in the slow position.
>>>
>>>Are there really two spped positions?
>>>
>>>Regards
>>>
>>>Marcel - EA3IN
>>>