FRG-7 led upgrade


This page is work in progress and may be updated frequently (last update : 2021-03-27 13:55 UTC). 

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On one of my FRG-7's, the main dial light bulbs are burned up, the rubber was falling apart and I know that getting these light bulbs is getting harder by the years. So I wanted to replace them with 5mm warm white leds. 


Main dial LED light

I designed a 5mm led holder which slips into the bracket for the light bulbs. First prototype fresh out of the printer. Looks good and it fits (turn 90° to lock in place). Tomorrow print another one and get some 5mm warm white leds (turned out, I only had bright white).Note the difference in diameter on the center section, it slips into place and when rotated 90 dgr. it locks.

When everything works out, I will publish the STL file on my website for download to print you own spare parts to keep your Frog in good shape. 


First good fitting prototype (the one on the table is a bad one).



Installing . . . . 


The result. The leds are less warm compared as the soft glowing original light bulbs. Maybe some red / orange dye could warm it up a little.


I made the design publicly available so you print your own but licensed it Attribution-NonCommercial 3.0 Unported (CC BY-NC-SA 4.0).
Meaning : 

  • Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • NonCommercial — You may not use the material for commercial purposes. 
  • ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.

It's not to be childish but it now happened a few times that a 3D design I made was sold by other people just because is was "Open source, so I can do anything I want with it" without any credits or even a token of appreciation


Step by step installation guide for MainDial LED's.

Step 1 : remove cover  

Step 2 : remove frames holding the S meter into place (one on both sides) 


Step 3 : remove Main Dial drum by loosen the nut on top (hold the drum while doing). 


Step 4 : locate and and note wiring routes of light bulbs. Remove light bulbs from frames (light bulbs shown below fitted in rubber holders).


Step 5 : de-solder light bulb wires from terminals 

Step 6: assemble LED's. 

  • Insert LED into 3D printed holder
  • Solder wires to anode and cathode (color to your preference). 
  • Use shrink tubing to prevent open contacts. 


Step 7 : place previous assembled LED's in frames. When desired, turn 90 dgr to lock into place. 


Step 8 : route wires as previous noted in step 4.

Step 9 :  combine cathode wires and solder to center of connection terminal.


Step 10 : solder a 680 Ohm 1W resistor to left of connection terminal.


Step 11 : combine anode wires and solder to free wire of 680 Ohm resistor 


Step 12 : when wanted, add some Orange Edding 3000 permant marker on the LED's to get a more "light bulb" warm glow.


Step 13 : re-install main dial drum and calibrate without antenna connected.

  • Set Preselect to 1MHz 
  • Set MHz to 1
  • Set mode to USB/CW
  • Turn main dial to minimum until mechanical block.
  • Rotate main dial drum as shown below and slightly fasten nut.
  • Turn main dial slowly to 0 at some moment you hear a high tone (crystal oscillator leek through)
  • Slowly dial to lower tone, until it (almost) gone (zero beat)
  • While holding drum, careful fasten nut
  • Adjust when needed.



Step 14 : re-install the cover (from step 1)

Step 15 : Enjoy the fruits of your labor. 



PB-1560 LED replacement (also the start for a PB-1380 bi-color upgrade)

Also there where 2 light bulbs defective on the MHz and PRESELECT PCB's. So I started to work on a drop in replacement for the PB-1560 PCB's (the light bulb PCB's between the MHz and Select) with 1206 SMD L:ED's with the same color. I use 2 LED's for each segment because the 1206 LED's aren't that bright and this way you get a better light spread. 



And while I was at it, I designed a PCB for the Bi-color Lock LED mod because I noticed that a few OM's would like to have the Bi-color Lock LED mod, but don't have the tools or opportunity to construct the circuit from scratch.  When it's ready I will be writing a instruction manual for it with lots of pictures.


I worked for a while on the PCB design and came up with this. All LED's on the front and for connecting the PCB's I use simple test pads to solder the wires to. Due to the soldermask soldering is easy and safe.


And the current limit resistors on the the back. I choose to use 2 resistors in parallel (1206) to allow fine tune the brightness. 


I ordered a bunch of 1206 WarmWhite LED's, soldered 2 in series and applied 6V to them. They look great in the drums.



Happy with these results, I ordered a batch of prototype PCB's. Production will take 3 days, and shipping up to 12. So now we wait.

Once they arrive I want to assemble 2 sets of PCB's for my FRG-7's and when all works out and I'm happy with it.

The other PCB's will be sold fully assembled and tested through my For-Sale page.  

While waiting for the PCB's to arrive

I hand milled 2 PCB's of the design from bare PCB. I soldered the SMD LED's to them and installed them in my FRG7 to see what it would look like. 


And although the LED's I ordered where warm white and look warm white when you use them, they are look very cool compared to the previouse installed 5mm warm white LED's for the main dial. 


So I soldered 4 SMD LED's to a wire and tipped the lensen with 3 different Edding 3000 makers (Yellow, Orange, LightBrown) to see if that would warm it more up matching the light of the main dial.  

perm-edding3000-5 perm-edding3000-6 perm-edding3000-13


The tests showed that when the SMD LED's where tipped with a small coat of orange it would match the color the best.  


The double tip on the MHz LED's was a bit too much. 


So I removed with alcohol and applied a single layer.  In real life it looks much better then on the photo. 


Happy with the results.  Now we wait for the PCB's to arrive.

PCB's have arrived.

After 2 weeks my PCB's arrived and in my lunch break I soldered the already purchased warm white 1206 SMD LED's and the resistors in place.



That evening I took my other frog who also had a few burned through light bulbs (visible in the main dial). 


Step by step installation guide for LED PCB's.

Step 1 : remove cover and remove screws on top of front edge (screws still fitted to show location)


Step 2 : remove screws from sides of front edge.


Step 3 : do pull the front edge a little so wires are better accessible. 


Step 4 : remove the screw of the cable clamp


Step 5 : carefully take out the 2 light bulb PCB's.  


Step 6 : note the wire-ing and write it down (my frogs both have the same wire colors, but I cant guaranty that for every one.  


  • +10V - White/grey - White/brown (3 wires in total)
  • GND - Black

Select PCB

  • Common - White
  • D - Yellow
  • C - Orange
  • B - Red
  • A - Brown


Step 7 : Remove frame from PCB's (don't loose the screws). 


Step 8 : solder wires to PCB's using colors marked in step 5. 



Step 9 : install frames. Remember to add the front frame on top of the Select PCB (shown right in the image below).


Step 10 : when wanted, add some Orange Edding 3000 permant marker on the LED's to get a more "light bulb" warm glow.

(no picture shown).

Step 11 : insert LED PCB's in to drums and fixate with previous removed screws (step 5)

Step 12 : test correct working (lookout when working with the cover removed, the FRG7 has some life mains connections around the transformer).   
Image below shows colors more pale then in real life (my camera of my phone can't handle this kind of mixed light sources).


Step 13 : remount the screw of the cable clamp (from step 4).

Step 14 : remount the screws from sides of front edge. (from step 2)

Step 15 : remount the screws from sides of front edge. (from step 1)

Step 16 : re-install the cover (from step 1)

Step 17 : Enjoy the fruits of your labor.  (image below showing still one burnt through light bulb from the main dial)




Step by step installation guide for BI-COLOR LED PCB.

Step 1 : remove cover  

Step 2 : Follow the wires of the LOCK LED PCB (white-red and white - black) to the PCB.


Step 3 : Cut them 1 cm from the PCB leaving a small piece of wire connected to the PCB.


Step 4 : Remove the LOCK LED PCB and replace it with the BI-COLOR PCB. 


Step 5 : Feed the wires through the clip in the base plate as shown below.


Step 6 : Pick them up and direct them to the front of your FRG-7. Remove the screw of the cover plate of the VFO. 


Step 7 : Place the LOCK LED Driver PCB on top of the VFO cover, trim the wires and connect them to the PCB.

  • Grey/Blue to LED_C
  • Red/Green to LED_R
  • Yellow/Green to LED_G


And screw the PCB to the cover of the VFO.


Note : forgot to take a photo from the install PCB (screwed to the side of the VFO cover). so used photo of Step 16 

Step 8 : Connect the LED_IN wire (White/Grey) to the connection point where the original White/Red wire was soldered.


Step 9 : Connect the GND wire (Grey/Blue) to the connection point where the original White/Black wire was soldered.


Step 10 : Now we have to make a decision. When the LIGHT switcht on the front is set to OFF. Do you want to : 

  • the LOCK LED on when locked and un-locked. If so go to step 11
  • the LOCK LED off when locked but on when un-locked. if so go to step 13.

Step 11 : Solder the pink wire to location shown below (this is +10V). 


Step 12 : Check the correct working of BI-COLOR LED modification.  By power ON your rig with LIGHT switched ON and MHz locked (image below shows LOCK LED orange instead of green). 


When the MHz is de-tuned the LOCK LED should glow red. 


When the LIGHT is switched OFF, the light you your should be off but the LOCK LED should be indicating the LOCK status (in image below showing un-locked). 


Turn the MHz to tuned and the LOCK LED should glow non-red (in image below showing orange instead of green). 


Continue to step 16.

Step 13 : Feed the pink wire through the base plate.


Step 14 : Trim the wire short. 


Step 14 : Solder the pink wire to the right of the 3 lip terminal (there should be white/grey wires soldered to it). 


Step 15 : Check the correct working of BI-COLOR LED modification.  By power ON your rig with LIGHT switched ON and MHz locked (image below shows LOCK LED orange instead of green). 


When the LIGHT is switched OFF, the light you your should be off and also the LOCK LED should be off. 


When the MHz is de-tuned the LOCK LED should glow red. 


Step 16 : Now every thing works, it's up to you to bundle the wires using Tyraps. 



Step 17 : Place the cover, power up your rig., tune into a broadcast station of your choice and enjoy the fruits of your labor. 



PCB's for sale?

So for now I have assemble 2 set of PCB's for my FRG-7 and I can reproduce the results. So the other PCB's will be sold fully assembled and tested through my For-Sale page.  

I hope to have them on that page the last weekend of March. 


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