Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Yaesu FT-990 Fan Problems  (Read 2983 times)
N5AS
Member

Posts: 26




Ignore
« on: April 24, 2011, 03:22:44 PM »

The fan on my FT-990 cycles normally, but starts out at slow speed with noise and finally reaches full speed after about 10-15 seconds.  I have it out on the bench and runs with a cogging noise, for lack of a better description, and never reaches full speed.  Are the motors repairable or do I have to buy a new fan?  It doesn't look like a normal fan motor to me.   Tom, N5AS
Logged
AC5UP
Member

Posts: 3835




Ignore
« Reply #1 on: April 24, 2011, 03:39:47 PM »

Considering the rig is approaching 20 years old I have a hunch a little bit of oil wouldn't hurt the fan...

I have never seen one, but if it's anything like a 12 volt brushless DC computer fan there will be a label on one side with an indentation under the label you can feel. Poke a hole in the label and peel it back enough to push some oil through the hole. Take your time. Exercise the fan, give it a little more oil, if and when it feels like it's moving more freely consider that Mission Accomplished.

Smooth the label back as best you can. If a tab of PVC tape feels like a good idea use one to reduce the chances of dust getting into the spindle.
Logged

Never change a password on a Friday                
N5AS
Member

Posts: 26




Ignore
« Reply #2 on: April 24, 2011, 03:53:16 PM »

This fan is a squirrel cage type 6 inch's long and about 1-1/2 inches in diameter.  It's not a bearing noise, more like an electrical.  Fan turns freely too.
Logged
W8JX
Member

Posts: 5631




Ignore
« Reply #3 on: April 24, 2011, 04:12:46 PM »

The fan on my FT-990 cycles normally, but starts out at slow speed with noise and finally reaches full speed after about 10-15 seconds.  I have it out on the bench and runs with a cogging noise, for lack of a better description, and never reaches full speed.  Are the motors repairable or do I have to buy a new fan?  It doesn't look like a normal fan motor to me.   Tom, N5AS

Bearings are going dry. A few drops of oil in right place should fix it. The noise is from bearing until it warms up enough to melt what little lube is left. I have revived many fan motors this way. Synthetic motor oil (5w30) seems to last longest.
Logged

--------------------------------------
All posted wireless using Win 8.1 RT, a Android tablet using 4G/LTE/WiFi or Sprint Note 3.
K7ZRZ
Member

Posts: 279




Ignore
« Reply #4 on: April 24, 2011, 04:42:03 PM »

Tom,

I've had the fan out of my FT-1000d, which I know to be the same type. The "detent-ness" that you feel when you spin the fan is the magnets of the stator and rotor passing each other.  I'm sure the suggestion of lubricating is right on. The only thing that touches in there are the bearing points, and you should lubricate them the best you can.
Logged

Brian K7ZRZ
N5AS
Member

Posts: 26




Ignore
« Reply #5 on: April 25, 2011, 04:56:46 AM »

Oiled fan bearings, no help.  Noise is direct from motor and still not coming up to speed. New fan (motor) may be the issue.  Thanks for the replies.  Tom
Logged
KE3WD
Member

Posts: 5694




Ignore
« Reply #6 on: April 25, 2011, 06:47:02 AM »

If this is a DC powered fan motor, good idea to check the line to it for any AC ripple before blanket ordering up a new fan.  Might just be a case where a filter cap or perhaps a regulator is what is really on the fritz, especially considering that it only exhibits the noise at the lowest speed setting. 

73
Logged
N5AS
Member

Posts: 26




Ignore
« Reply #7 on: April 25, 2011, 07:41:48 AM »

It is running slow on a 12V bench supply too.
Logged
K8AXW
Member

Posts: 3737




Ignore
« Reply #8 on: April 25, 2011, 09:03:30 AM »

Any way to get it apart or blow it out with canned air?  If you can get it apart, check any spacers at the ends of the shaft.  If they're worn it's possible the rotor is rubbing the bearing housing.
Logged
K7ZRZ
Member

Posts: 279




Ignore
« Reply #9 on: April 25, 2011, 01:58:08 PM »

Tom,

If you can come up with a part number, you should first call Yaesu - parts department and give them the part number. Chances are they will have that part still in stock. Just asking about parts for an FT-990 will likely get you a "no longer stock those parts" as a thoughtless response.  That's a common story, but you'd be surprised what they still have available if you can give them a part number to look up.
Logged

Brian K7ZRZ
VK6ABM
Member

Posts: 11




Ignore
« Reply #10 on: April 27, 2011, 12:44:05 AM »

The fan on my FT-990 cycles normally, but starts out at slow speed with noise and finally reaches full speed after about 10-15 seconds.  I have it out on the bench and runs with a cogging noise, for lack of a better description, and never reaches full speed.  Are the motors repairable or do I have to buy a new fan?  It doesn't look like a normal fan motor to me.   Tom, N5AS

Tom

While I have not seen the motor I have assisted a VK4 in fixing that same fault by replacing a 1uF 50volt electrolytic on the motor pcb

I don't have the schematic of the motor pcb so don't know for sure what the capacitor does (could be a ramp timer) but from descriptions the motor is a stepper type - wonder if you do get into that area maybe you could take a closeup photo of the board - I am keen to know all about it (the VK did not have a camera)

73
Brian
Logged
N5AS
Member

Posts: 26




Ignore
« Reply #11 on: April 27, 2011, 05:37:57 AM »

The fan is running at normal speed now and no cogging noise either, after a little clock oil in the bearings  Grin.  Even though the fan rotated freely with some duration the oil must have been needed anyway.  Thanks for all you help and input.  Tom
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!