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: Possible lightning hit on Yaesu FT-950  (Read 2054 times)
N4NYY
Member

Posts: 4748




Ignore
« on: July 02, 2012, 08:53:21 AM »

First the good news. The 950 works and transmits.

Lightning came into the cable TV line and took out my last tube TV, bi-directional amp, and cable modem.

The rig was unplugged from antenna switch. The power supply was unplugged from wall. My laptop was plugged into a power strip as was the TV that got hit. The power strip was NOT plugged into the wall.

The only loop I could find was the USB-serial cable going from the laptop to my 950. Again, the common point was the "unploughed power strip" connecting the TV and the laptop.

My 2 electrical and shack grounds are bonded.

I tried another laptop with no luck.

It is either the USB-serial adapter cable or the 950.

What am I looking at with the 950? I have done some repairs myself.
Logged
N4NYY
Member

Posts: 4748




Ignore
« Reply #1 on: July 02, 2012, 01:47:14 PM »

Well,

Looks like the USB-serial adapter can be ruled out.
Logged
K8AC
Member

Posts: 1466




Ignore
« Reply #2 on: July 02, 2012, 02:41:28 PM »

What you've described seems to be quite common in cases of lightning strikes.  Chances are excellent that it's the PC interface in the 950.  In a couple of my old Icom rigs (781, 765) Icom included a couple of "buffer" transistors that would blow if a surge came in on the CIV line.  That was necessary as the next stop along the line was the CPU.  The transistors were quite easy to replace and cost less than a dollar a piece.  Check the schematic for the 950 and see if there isn't something similar on the PC interface.  Another thing I've run into when a surge came in on the PC interface line (again, CIV line on 781)  was that the connector was not grounded to the rear chassis directly.  The connector was mounted on a circuit board and the ground side of the connector went through an inch or two of PC board land before going to ground.  In my case, that trace was just vaporized, or at least blown into very small pieces.  I replaced that with a piece of wire to ground that that solved the problems. 

Another thing to watch out for is the presence of a telephone line in the shack.  Chances are you have one and the phone line is coiled up around or near other rig cables.  I had one case where the jolt entered the shack on the phone line and jumped to another cable.  Even though it was an underground phone line and was properly grounded at the outdoor telephone box, the phone line was blown open at that point and enough of the surge got through to do some damage.

73, Floyd - K8AC
Logged
N4NYY
Member

Posts: 4748




Ignore
« Reply #3 on: July 02, 2012, 02:49:03 PM »

What you've described seems to be quite common in cases of lightning strikes.  Chances are excellent that it's the PC interface in the 950.  In a couple of my old Icom rigs (781, 765) Icom included a couple of "buffer" transistors that would blow if a surge came in on the CIV line.  That was necessary as the next stop along the line was the CPU.  The transistors were quite easy to replace and cost less than a dollar a piece.  Check the schematic for the 950 and see if there isn't something similar on the PC interface.  Another thing I've run into when a surge came in on the PC interface line (again, CIV line on 781)  was that the connector was not grounded to the rear chassis directly.  The connector was mounted on a circuit board and the ground side of the connector went through an inch or two of PC board land before going to ground.  In my case, that trace was just vaporized, or at least blown into very small pieces.  I replaced that with a piece of wire to ground that that solved the problems. 

Another thing to watch out for is the presence of a telephone line in the shack.  Chances are you have one and the phone line is coiled up around or near other rig cables.  I had one case where the jolt entered the shack on the phone line and jumped to another cable.  Even though it was an underground phone line and was properly grounded at the outdoor telephone box, the phone line was blown open at that point and enough of the surge got through to do some damage.

73, Floyd - K8AC

Another ham emailed me and says it is Q3606 on the control PCB. But it is SMD and also glued in. So if I get the SMD out, the glue is another factor.

The control PCB costs $140, but would require a full alignment. I cannot perform that with the test equipment I have. I have test equipment for older tube gear.
Logged
KE3WD
Member

Posts: 5694




Ignore
« Reply #4 on: July 02, 2012, 03:37:16 PM »

Glued in SMT transistor is a nonproblem.  First desolder the legs, then apply heat to top of transistor plastic case with the iron.  Then pluck the transistor from the board with needlenose pliers.   A slight twisting motion sometimes helps, but never force things. 

Adhesives can generally be broken with temperature transitions, if it is really glued down, try heating with the iron followed immediately with freeze spray and then the needle nose lift.  Repeat if necessary, never force. 

Of course, use the DMM on diodes scale to first ascertain the health of the transistor as it may be fine. 

73
Logged
W4VR
Member

Posts: 1191


WWW

Ignore
« Reply #5 on: July 02, 2012, 05:55:15 PM »

Take it to your local ham radio store and have them take a look at it.  That's what I did with a TS-940 that was suspect for a lightning hit and they gave me a letter that stated the radio had been hit by lightning.  The insurance company bought me a new radio!  Don't try to repair that radio yourself...you may end up burning something else up unless you have SMT equipment.
Logged
N4NYY
Member

Posts: 4748




Ignore
« Reply #6 on: July 02, 2012, 06:43:55 PM »

Glued in SMT transistor is a nonproblem.  First desolder the legs, then apply heat to top of transistor plastic case with the iron.  Then pluck the transistor from the board with needlenose pliers.   A slight twisting motion sometimes helps, but never force things. 

Adhesives can generally be broken with temperature transitions, if it is really glued down, try heating with the iron followed immediately with freeze spray and then the needle nose lift.  Repeat if necessary, never force. 

Of course, use the DMM on diodes scale to first ascertain the health of the transistor as it may be fine. 

73

It is a 16 pin chip. Don't ask why it is called Q.
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!