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Update The Meter Lighting of Your MFJ Giant Watt Meter

from Steve Fetter, WA8UEG on July 12, 2017
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Update The Meter Lighting of Your MFJ Giant Watt Meter
By Steve Fetter -- WA8UEG

I just finished upgrading my rotor control box and while doing so added the Ham Supply LED board for illuminating the meter. Now my MFJ giant swr/watt meter looked dim and drab in comparison. I decided to take a look and see if I could use the same board to illuminate the MFJ meter and sure enough it looked very doable.

It turned out to be a really simple modification. After receiving the new board assembly took about 15 minutes. The MFJ meter is lit by 2 peanut lamps, one pulled right out and the other had a small amount of glue holding it in place but when I applied a small amount of pressure with a small screwdriver it popped right off. I cut the peanut leads off leaving about 3 inches in case I ever wanted to use them in a future project. Now there were 2 options to mount the new board with the LEDís.

The new board has plastic spacers that can be installed for mounting purposes, if you use them you will need to leave each LED mounted away from the board about Ĺ inch then use the supplied glue dots to hold the board in place. I decided to mount the LEDís tight to the board which only causes one problem, the voltage connection wires on the PC board are on the same side as the LEDís and could short out on the front panel of the MFJ. To make sure this did not happen I applied a dab of liquid electric tape on the circuit board where the supply wires were soldered to the PC board. You could use anything that would insulate those connections like electric tape, a thin piece of plastic, etc. but the dab of liquid was neat simple and does the job nicely.

I then inserted the LEDís above the meter in the same slot the peanut lamps were in, centered the middle LED to the middle of the meter and secured the board to the back of the front panel with the supplied glue dots.

The LED Illuminator kit is $9.95 plus a couple of bucks to ship. The meter is now evenly illuminated and easy to read.


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Update The Meter Lighting of Your MFJ Giant Watt Meter  
by G7MRV on July 12, 2017 Mail this to a friend!
I have done essentially the same mod to an MFJ tuner's SWR meter,

The only thing I would say though is that the total cost of components required is around a tenth of that of the LED kit (or a twentieth of the assembled product). The product is nothing more than three LEDs, a current limit resistor, cap and diode, on a pretty board.

Mine is built from simply wired together parts protected with shrink tubing on the joints and hot glue to secure. Around 50p in British money if i'd had to buy the parts (under a $?), but they are parts to be found in most everyones junk boxes
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by SWMAN on July 12, 2017 Mail this to a friend!
Looks really good, good job.
 
Update The Meter Lighting of Your MFJ Giant Watt Meter  
by WA8UEG on July 12, 2017 Mail this to a friend!
Can't disagree. It would be cheaper to homebrew one but for the difference in cost & time I felt it worth a few extra bucks. I had ordered the conversion kit for my rotor box so I would have computer control plus point and shoot so I didn't have the extra cost of shipping.

I am in the process of rebuilding a HP-23A for my Harvey Wells TBS-50 and MR-1 Comanche plus restoring a HQ129X & a HQ140X as well as some other projects so decided this was a quick and easy $9.95 solution for the meter light, time was more of a factor for me than cost :)
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by W4KVW on July 12, 2017 Mail this to a friend!
The lighting was repaired early in ownership with bright white LED's.Had Zero success with all of the stray RF in my shack with the amplifier on when using that meter. Changed to an Autek WM-1 & all of that stray RF went away.Appears the stray RF issue was withing the MFJ Giant Wattmeter since nothing else was changed.Loved that huge display but could not live with the stray RF.

Clayton
W4KVW
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by WA8UEG on July 12, 2017 Mail this to a friend!
Wow, I have not had any problems and as you can see in the top picture or on my QRZ page it sits right next to my AL-1200 and below my antenna switch. You using open wire feed line?
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by W4KVW on July 12, 2017 Mail this to a friend!
It did it on my Mosley TA-53M,G5RV,& 160 meter Half Sloper with my 811H & my PW-1.Only change was the wattmeter.

Clayton
W4KVW
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by WA8UEG on July 12, 2017 Mail this to a friend!
Strange, my bet is you had a bad solider joint or ground connection somewhere in the MFJ.

I see we had a QSO on 20 SSB a couple years ago!

73
Steve
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by W4KVW on July 13, 2017 Mail this to a friend!
Nobody would ever believe there was an issue with anything in an MFJ product. LOL I do paper logs myself so I'll take your word on the QSO.God bless & enjoy the new lighting. {:>)

Clayton
W4KVW
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by K6UJ on July 13, 2017 Mail this to a friend!
Nice mod ! Thanks for sharing.

Bob
K6UJ
 
Update The Meter Lighting of Your MFJ Giant Watt Meter  
by VE3TMT on July 14, 2017 Mail this to a friend!
I've been using inexpensive 12V LED rolls from China for years. Added them to my amp, rotor, undershelf shack lighting, back of my monitors. They're cheap, run right off 12V and you can cut them every three LEDs.

I also bought the 3 LED strips for about 1/20th of what the rotor strips are selling for. They are self stick, no circuit board, but much, much cheaper.
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by SWMAN on July 15, 2017 Mail this to a friend!
TMT,
Would you be able to share where to buy those rolls of LEDs, an American dealer would be good if you have it. Thanks, Jim W5JJG
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by VE3TMT on July 16, 2017 Mail this to a friend!
http://www.ebay.com/itm/Cool-White-5M-600Leds-SMD-3528-Led-Strip-Lights-Flexible-Ribbon-Ultra-Bright-12V/151915426106?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D41375%26meid%3Da274cd47a12846dd95abd780de99b278%26pid%3D100011%26rk%3D1%26rkt%3D6%26sd%3D150571845268
 
RE: Update The Meter Lighting of Your MFJ Giant Watt Meter  
by SWMAN on July 17, 2017 Mail this to a friend!
TMT. Thank you for the info.
 
Update The Meter Lighting of Your MFJ Giant Watt Meter  
by PE1HZG on July 22, 2017 Mail this to a friend!
I found that the peak meter would overshoot with SSB in peak signals, giving peak readings that are more than a bit optimistic.

To fix, I added a resistor 47K betweek the emitter of Q1 and the join of R11, pin 3 of U1, pin13 of U1.
This is easy to do by lifting the emitter leg of Q1 and put the resistor in series. Peak reading is not affected and the meter is a lot more stable.
 
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