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

donate to eham
   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: 811 causing RFI  (Read 12482 times)
K4RVN
Member

Posts: 261




Ignore
« on: March 17, 2016, 06:38:27 PM »

Bill, K3SFK, have you any news back from Ameritron on your amp that was causing RFI?
I sure am curious to see what they reported.

Frank k4RVN
Logged
W1QJ
Member

Posts: 2991




Ignore
« Reply #1 on: March 17, 2016, 06:40:32 PM »

Hi Frank, is that the one that caused problems when it was turned off?  I am sure the problem had to be bad bypass caps on the incoming AC line.
Logged
K4RVN
Member

Posts: 261




Ignore
« Reply #2 on: March 22, 2016, 05:44:29 PM »

Yes Lou, He sent it back to Ameritron but I would sure like to see what they reported. I just got back from a week's vacation down on the South GA. Coast. Had some good seafood and nice weather compared to here as it is chilly tonight. Thanks for the reply.

Frank
Logged
W1QJ
Member

Posts: 2991




Ignore
« Reply #3 on: March 22, 2016, 06:54:40 PM »

Glad you had nice wx for your vacation Frank.  We woke up to snow on the ground here on the first day of spring.  Nice huh?
Logged
K3SFK
Member

Posts: 12




Ignore
« Reply #4 on: March 31, 2016, 04:55:08 PM »

3/31/2016

To: Frank k4RVN and other interested hams;
Fr: bill bartholomew, K3SFK
Re: Ameritron Amp 811 with heavy RF problems - update report

Thank you for your reminders to update everyone on this frustrating problem with my 811 amp.   Here is what occurred and you will find that the information is still 'lacking'.

1). I mailed the amp back to Ameritron per their recommendations.
 
2). When I called them to ask about the repair progress, they stated that they knew what was wrong and that it was an 'easy fix'.  However, the repair person did not describe the details.  I waited to get the amp back with the invoice, AND the invoice did NOT have any description of the repairs made.......I was surprised.   However, the cost of the actual repair (not including shipping) was only $60.00 so I was satisfied and silent on pushing for more details. 

I am sorry that this lack of detail will not help explain more clearly 'what was really wrong'.  If their invoice had explained what repair was made, this would hopefully satisfy us all about the mystery RFI which originally was significant and heard on radio receivers all around the house.  The Ameritron repair invoice number is 53966.  I could try to re-contact them and see if additional details would be given over the phone from a technician?

3). The amp was returned to me in about two weeks without mailing damage, and it appears to BE FIXED....mostly.  When the amp was plugged back into AC, even though it was turned off, there was still minor (about 5% buzzing remaining) RF coming through the speakers of radios in the shack.  I checked further and found that the multi-plug power strip appeared to be the source of the remaining buzzing sound on the shack receivers.  I replaced the power strip with a DX Engineering $80 (higher quality?) power strip which seems to reduce the interference also. 

My final conclusion is that I still do not understand precisely what was wrong and am thankful that the problem appears to be gone.   

If anyone has informed insights on how this problem occurred and how other hams can deal with similar problems, your advice is welcomed and appreciated.

Sincerely,

bill bartholomew  K3SFK
Logged
W1QJ
Member

Posts: 2991




Ignore
« Reply #5 on: April 01, 2016, 04:33:03 AM »

Recently another ham on a different forum reported a similar problem.  He called Ameritron and they told him he had to change the fuse size when switching to 240v.  When he changed the fuse the RFI went away.  I suspect that is why there was no mention of the fix.
Logged
N3QE
Member

Posts: 5598




Ignore
« Reply #6 on: April 01, 2016, 05:08:51 AM »

Recently another ham on a different forum reported a similar problem.  He called Ameritron and they told him he had to change the fuse size when switching to 240v.  When he changed the fuse the RFI went away.  I suspect that is why there was no mention of the fix.

Be ready for a big stretch here: There was a poor contact in the fuse socket that was making RFI with just filament load? and pulling out/re-inserting fuse cleared up a tiny arcing-under-low-current arc? Oh, that's a stretch.

I've got all sorts of crufty(*) old stuff in the shack and have never heard fuse-induced RFI. Certainly not "wrong fuse size caused RFI".

(*) Including equipment that actually was from Cruft Lab at Harvard! And the Cruft Lab book!

Update: Oops, wait, nevermind. Forgot today was April 1!
« Last Edit: April 01, 2016, 07:15:34 AM by N3QE » Logged
K4RVN
Member

Posts: 261




Ignore
« Reply #7 on: April 01, 2016, 06:57:51 PM »

Thanks for reply Bill. I suspect it was the caps on the line power cord where it enters the amp as others mentioned in your original post. Glad you got it resolved by Ameritron.
Sure hoped to get the answer to what would cause the problem but no big deal just curious.

Frank
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!