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: Meter light bulb replacement on Icom 751A  (Read 3054 times)
K4RVN
Member

Posts: 812




Ignore
« on: June 18, 2013, 07:13:04 AM »

Can anyone tell me how to get to the meter bulb and where I might find a replacement for an Icom 751 A?
I don't know how to access the bulb or bulbs.

Thanks,

Frank K4rvn
Logged
AD6KA
Member

Posts: 2238




Ignore
« Reply #1 on: June 18, 2013, 08:26:59 AM »

Here's a IC-751A Service Manual download,
should be of some help:
www.radiomanual.info/schemi/IC751A_serv.pdf

I've replaced meter lamps on two Kenwood
HF rigs but not any Icoms. Probably a similar
process. Look up which screws to loosen/remove
to tilt down the front panel to access the lamp/s.
Typically a "grain of wheat" type bulb running off
the 12v rail, but you can measure the exact voltage.
Radio Shack stocks a couple different 12v "grain of wheat"
type bulbs. Or, use an LED....don't forget the resistor.
Here's a resistor calculator for the LED:
http://led.linear1.org/1led.wiz

LED's are nice replacements as they last forever
and, if you like, you can choose a spiffy color like
bright blue. Or not. Some LEDs have a kinda narrow
angle of light projection. I have read that if you lightly
buff them with some fine steel wool it will improve this,
but I have good results without doing it.

GL with your project!
73, Ken  AD6KA
Logged
K4RVN
Member

Posts: 812




Ignore
« Reply #2 on: June 18, 2013, 11:55:09 AM »

Thanks for reply Ken. I  have looked at the service manual several times before posting for help, but found nothing. That does not mean it is not there.  I have also asked on the 751 A yahoo group. I'll take a look at Radio shack once I get to the existing bulb. A friend of mine K4TLJ just sent me some info how to get to the bulb. I ha done many searches on the net and could not find something
which should be so simple. Thanks again for your help, I think I have enough info now to locate and replace it.

Frank
Logged
W0BTU
Member

Posts: 1853


WWW

Ignore
« Reply #3 on: June 18, 2013, 02:21:18 PM »

Take the top cover off. You can see the back of the meter when you do. The S-meter lamp with the rubber holder pulls straight out the back of the meter.

You have to cut the 2 lamp wires (cut them fairly close to the lamp) to completely remove it.
Logged

K4RVN
Member

Posts: 812




Ignore
« Reply #4 on: June 18, 2013, 03:18:12 PM »

Thanks Mike,
I have it removed now and trying to find a replacement to fit in the hole. Going to RadioShack and look at their miniature 12 volt bulbs. I plan to install a resistor to make it less bright.

Frank
Logged
W0BTU
Member

Posts: 1853


WWW

Ignore
« Reply #5 on: June 18, 2013, 04:49:41 PM »

I have it removed now and trying to find a replacement to fit in the hole. Going to RadioShack and look at their miniature 12 volt bulbs. I plan to install a resistor to make it less bright.

Perfect! Sounds like a plan.  :-)

I got tired of the lamp burning out (even with a dropping resistor), and finally used an LED with a dropping resistor in both my IC-751A and IC-765. But in my opinion, the incandescent lamp looks a lot better that any LED that I tried (and I tried a lot of them).

If you use a clear LED, roughen it up with steel wool or fine emery cloth to give it a frosted appearance. That way, it will illuminate the S-meter more evenly.

You have a very good rig. Does it already have the standard modifications and fixes?
Logged

K4RVN
Member

Posts: 812




Ignore
« Reply #6 on: June 18, 2013, 08:19:23 PM »

Mike I bought a miniature bulb that fit in the grommet that held the old bulb. I did not know how to get to the bulb but it was easy to remove the top cover and pull the rubber grommet out from the meter housing. I had plenty of wire on the existing bulb but both the same color so had to use my multi- meter to determine the plus and minus. I found a Radioshack bulb that fit into the grommet and soldered it on. It only draws 25 ma and is just the right amount of light for my old eyes. Not too bright and not too dim, looks nice I think. Cost was 1.49 . It is not a led.
I was very fortunate on the ebay radio in that it had the Piexx memory board and a Piexx serial port installed. I don't know what other mods may have been done but it is a great radio
as I did an A-B comparison with my Omni 6 plus on receive with a five band hex beam and could not declare a winner. Also it appears to be dead on frequency with WWV and other high class transceivers I have talked to on the air. I appreciate all the replies and the lamp is now in my radio and undergoing a shake down to see how long it lasts.

Frank
 
Logged
AD6KA
Member

Posts: 2238




Ignore
« Reply #7 on: June 19, 2013, 11:32:36 AM »

Hi Frank:

Glad that your project was successful and painless.
Now you know how to do it. Going forward you can
do it on other HF rigs or help others do it.
Even little DIY projects like this are rewarding,IMO.

Quote
I was very fortunate on the ebay radio in that it had the Piexx memory board and a Piexx serial port installed. I don't know what other mods may have been done but it is a great radio
as I did an A-B comparison with my Omni 6 plus on receive with a five band hex beam and could not declare a winner.

I know a couple guys with IC-751A's. They are terrific
radios...and, I think, an underrated radio in the community.
Yeah, a little long in the tooth, but so what?

You done good in picking it up. I would highly recommend
that you refrain from doing any mods on it.
(I know, you didn't say you were going to, but I thought I'd
throw that out there anyway.)
It works great, has the Piexx Mods for CAT control,
very good performer. You scored, buddy!
73, Ken  AD6KA
Logged
W0BTU
Member

Posts: 1853


WWW

Ignore
« Reply #8 on: June 19, 2013, 08:23:21 PM »

I would highly recommend
that you refrain from doing any mods on it.

Why do you say that? There are many simple and worthwhile mods and fixes for common issues for the IC-751A (etc.) that are very worthwhile.

Now, if a person doesn't have a clue as to which end of a soldering iron gets hot, or doesn't know the difference between rosin and acid core solder, that's really good advice.
Logged

AD6KA
Member

Posts: 2238




Ignore
« Reply #9 on: June 20, 2013, 12:43:03 PM »

I would highly recommend
that you refrain from doing any mods on it.

Why do you say that? There are many simple and worthwhile mods and fixes for common issues for the IC-751A (etc.) that are very worthwhile.

Now, if a person doesn't have a clue as to which end of a soldering iron gets hot, or doesn't know the difference between rosin and acid core solder, that's really good advice.

Point taken, OM. You're right. Some simple mods are very useful.

I just get sad when I read posts on these forums where
hams jump into perfectly good rigs, muck them up, then
are out a limb and need help. Sometimes costly help.
No relection on this poster, I'd like to clarify that.
73, Ken AD6KA
Logged
K4RVN
Member

Posts: 812




Ignore
« Reply #10 on: June 20, 2013, 12:49:04 PM »

Ken,I have never worked on a receiver in my experience as an amateur, so don't plan any mods myself. If My 751A gets a problem I am also fortunate to be within an hour of Bill at Clairmont Radio and TV a well known repair service for ham radio equip. I did look at your site Mike , quite a setup. I built a beverage antenna last winter and notice the 751A has a receiving only ant. jack so will be trying that on the general broadcast as well as other bands soon. Your homebrew amp showed me a lot of parts I used to have in my junk box. I gave away most of my stuff for amps. I saw one site that said to remove the front panel on the 751A to replace the s meter light so glad I got the straight info from this forum which only meant removing the top cover. I got my W2eny Icom
 radio specific headset boom mic. yesterday, works great with this radio. Good audio reports with the electret mic.

73,

Frank
« Last Edit: June 20, 2013, 12:54:21 PM by K4RVN » Logged
W0BTU
Member

Posts: 1853


WWW

Ignore
« Reply #11 on: June 20, 2013, 05:10:56 PM »

Sounds good, Ken. You had some good advice.

Happy to help, Frank. And if you liked my amp at http://www.w0btu.com/833C_linear_amplifier.html I added quite a bit of text there early this morning. You will love your Beverage. Just follow the directions on my Beverage antenna page and I don't think you will be disappointed.
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!