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: Ameritron AL-811 amp questions  (Read 2917 times)
K7MH
Member

Posts: 455




Ignore
« on: September 28, 2004, 10:11:41 PM »

Picked up a used one that has a burned out lamp in the grid current meter. Is the lamp easily aquired, i.e. Radio Shack, or do you have to get a replacement from Ameritron? Also, this one has computer case type screws for the cover. Are those the correct screws that Ameritron uses? I ask because there were a few missing so not real sure if they are the original type of screws. Thanks for your assistance, Mike K7MH.
Logged
WB2WIK
Member

Posts: 21836




Ignore
« Reply #1 on: September 29, 2004, 08:33:51 AM »

When my lamps burned out in the AL-80B (I don't have an AL-811, but I think the meter/lamp stuff is similar) I replaced them with ultra white LEDs and small resistors.  I think I used 470 Ohm 1/2 watt resistors, per recommendation of the LED manufacturer (to provide the right series resistance for a 12V source).

I glued the white LEDs behind the meters using small dabs of RTV.

Seemed prudent to do this rather than replace the bulbs with "original type" ones, which would likely only burn out again in a couple of years like the first ones did.

The screws in the Ameritron amps I've played with, including my AL-80B, are #6-32 Phillips head machine screws about 1/4" long, and black in color.  They thread into pressed-in inserts (PEMs) in the chassis.  

WB2WIK/6
Logged
K7MH
Member

Posts: 455




Ignore
« Reply #2 on: September 30, 2004, 08:13:31 PM »

Thanks for the info. Sounds like not to bad an idea. I will give that some consideration. Would still like to know if the lamps are commonly available. If they are 12 vdc, are they common in the automotive supply world?
Some of the interior auto lights are pretty weird these days!
Logged
N3ZKP
Member

Posts: 2008




Ignore
« Reply #3 on: October 02, 2004, 02:53:06 PM »

Have you actually looked at the little lamps?

Unless they are different from what's in the AL-80 series (and I doubt it) they are 12v "grain of wheat" lamps avaliable at RS.

They have pigtails and are soldered in the circuit. Takes about five minutes to replace tham, after you get the cover off the amp.

Lon
Logged
K7MH
Member

Posts: 455




Ignore
« Reply #4 on: October 02, 2004, 08:30:33 PM »

 I have looked at them and they have the leads coming in from each side of the lamp which is a horizontally mounted lamp in the front of the meter. I didnt see anything at Rad Shack that was similar but there were a few empty lamp boxes. I have some 12vdc 25mA mini lamps, which is more what I know to be a grain of wheat lamp, where the leads come in from the bottom of the lamp. Perhaps they would be good replacements. I hate to have to pay $10 shipping for a couple 90 cent lamps from Ameritron!
Logged
N3ZKP
Member

Posts: 2008




Ignore
« Reply #5 on: October 03, 2004, 06:08:55 AM »

Use what you have on hand; they'll probably work fine. I don't remember which ones I used from RS, but that sounds about right. Since the schematic gives no detail on the lamps, I doubt the current rating is of much importance.

The next time more than one burns out (or both on one meter) I'll replace them with LEDs.

Lon

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!