This short video shows how to replace the incandescent bulbs used to light up the S-meter on the Yaesu FT-736R VHF/UHF rig. It also describes why I chose not to convert to LED illumination at this time.
Great vid, and I never knew my FT-736R had that tilt-out feature of the front panel. My LEDs are ok so far, but when I need to, I have an excellent guide... Thanks!
Thank you for the video Alan. Great piece of info I gleaned from this video was the hinged faceplate on the Yaesu radios. This is a good piece of info because I plan on investing in some older radios and I am a Yaesu fan. :-)
+mPD780C1 to be clear on the terminology: straw hat =/= inverted cone, those are to different head types, straw hats are typically shorter with a flatter but still convex lens and as such have a wider diffusion angle than "normal" LEDs
look up your local dollar store around christmas for a cheap source of inverted cone's, the cheapest strings use them, just underdrive them (5-10mA) and they should last forever
I though about these LEDs as well. On the other hand you don't really have to use the top reflecting surface of the light pipe. Its there because with incandescents it was needed. A small SMD LED that just points down into the light pipe would not need it. A round bulb/LED is easier to install though that a LED where you have to build some kind of fixture for first (glueing it to the side of something that fits the hole might be the easiest way).
Sure wish Kenwood had done something similar with the front panel of the TS-940S...although the front panel does tilt forward to get to the S-meter and LCD backlight bulbs the panel can actually fall off if you're not careful. Darn grain of wheat style incandescents! Nice fix Alan...73 - Dino KL0S
The issue with backlighting using LEDs is "viewing angle". A narrow angle almost always results in a spotlight effect. Use a wide angle LED and/or remove the lens. SOMETIMES, that works. OTOH, an incandescent's yuuge 5X cold-start (inrush) current can be limited to minimize the "Miller-Larson" stress on the filament. Fortunately, for tiny Grain Of Wheat lamps (typically around 25mA running current), the inexpensive LM317L voltage regulator can easily be configured as a current regulator using one resistor. The datasheet shows how. A bonus is, 5% change in running current causes a ≈ 50% change in incandescent lamp life. The caveat is, to get 100% running current, the supply voltage needs to be at least 1.2V above the lamp's rated voltage. So, use 12V lamps instead of 14V lamps. I made this simple modification to my olde Kenwood TS-120S & TS-130S rigs 'bout a dozen years ago. The lamps stopped burning out. At about 95% running current, I can't tell any decrease in lamp brightness.
Great video. Very informative and well done. As for the LEDs, I don't understand why people love LEDs so much. In my opinion, they give off an obnoxious glare which the human eye cannot properly focus on. Here in Tokyo, they're converting all street lights and such to LEDs. Terrible idea. I wouldn't be surprised to learn that in the future, there will be a medical health issue related to prolonged exposure to LEDs. They're already discovering adverse affects of these with pregnant women. But that aside, I dislike the 'look' of them compared with the warm glow of incandescents. That's my main reason why I dislike them. The glare and their appearance. Glad you didn't repair this now classic unit with LEDs changing it's original configuration (and degrading its value). As you noted, its design was intended for incandescent lighting making use of silver paint for reflection, etc. To change that would be to in a way, butcher or jury rig the thing to accept the newer lighting format. As in most antique/classics such as vehicles, furniture, etc. it's always a bad idea to 'upgrade' some component on it to match the present fashion. It destroys the value and original beauty of the thing, dates it to the present and is generally considered destructive to the original engineering and design. That's why you won't see anyone putting LED headlights in their classic Porsche, Triumph or Shelby Mustang. Though there are some who do this, it's a mistake and future owners, users and historians always decry such modifications. But to each his own. ;) Cheers from Tokyo.
Ty so much for your videos. Between yourself, Buddy, Peter, Paul, Mike and Vern I've learned so much. Something I've never seen, is how to install TMP connectors. I know from warnings to always grab them by the connector, but if a radio comes in with one broken, how to install these TMP coax connectors? Which connectors are sized for which coax? I hear about a crimp tool but no one seems to have one. Not even on eBay lol
Looks like you should be able to take a standard LED, and to combat its forward lighting behaviour, sand its top lightly, and paint the sanded spot white or silver.
I have a Citizen model BLPL-600 and after I switched over to a different Antenna suddenly see that my meter light(s) is not working now. The meter works perfectly but now have no back light. Does anybody know what kind or brand of bulb my radio takes? Unfortunately I cannot find any info online about this model CB Base Station I just bought. Thanks !!!
But house light bulbs are 100 watts and 120watts but the oils on our fingers don't create thermal stresses on the light bulbs glass but a preamp tube and power tube can get thermal stresses and fracture the glass from our oils on our fingers?
So substituting higher current rating light bulb lamps don't damage or harm the circuit under test that is rated for lower current rating light bulb lamps?
Is this the same for preamp and power tubes because I seen electronic techs grab the tube glass to pull them out of the circuit and install them in old TV had tubes and old radios used tubes. Also why doesn't a house "lamp bulbs" not have the same glass envelope that is bad for oils on our fingers to cause the temperature of the glass to vary and fracture the glass?
how about damage to the circuit board that is sourcing the current since the higher current bulb lamp will want to draw more current or overload the lamp output port on the circuit board?
Could anybody please let me know what the ratings of these bulbs are? I searched all over but without success. I need to make sure that ordered replacements will provide sufficient light as even the orginal bulbs make the S-meter barely readable. Thank You!
If you put in a Higher Current bulb/lamp will this damage the circuit because the Higher Current Bulb/lamp would "need more current" in order to light the bulb/lamp which is considered overloading the circuit? Most rating for light bulb lamps tells you the voltage and wattage but they don't tell you much about how much current it needs in order to light the filament in the bulb or lamp. The more filament coils and thicker the filament this is considered a higher current bulb/lamp?
Is it true that its really bad to put your fingers on a light bulb because the oils on your fingers will cause dead spots and can explode the light bulb? I'm guess its the same for tubes in radios and amplifiers, if you use your fingers on the light bulb and tubes glass envelope it will cause dead spots and crack the glass?
Oils in your fingers can change how the heat is distributed on the glass envelope of a high power light bulb or vacuum tube. If the temperature across the surface of the glass varies too much, it sets up thermal stresses which can fracture the glass.
Amigo, percebi que você é brasileiro. Não sei se você tem domínio da língua inglesa porém estou com um projeto de site onde eu traduzo vídeos técnicos de diversos youtubers como w2aew, EEVBlog, Mr Carlson's Lab gratuitamente, o que você acha?
bom dia amigo meu nome e antonio não domino a lingua inglesa mas minha irmã tem min incentivado, e tenho muita vontade de apreder porque sou radioamador gostaria muito de fazer contatos com radioamadores estrangeiros ok a pouco tempo ela não sabia pra onde ia o ingles hoje já e a terceira viajem internacional que ela faz para holanda e de lá vai para varios lugares e não tem dificuldade mas como seria este projeto que voce falou
SMD leds down each side of the meter would give a much better spread of light. This thing looks like it has footlights and does not fit the general high tech look of the rest of the radio.
Just did a 736, standard LED. Works good. Bottom terminal is the Negative/ground trace. Important for LED
Very nice video. Nice presentation. Many hams' videos are ruined by their trying to be comedians. Most enjoyable.
you can use frosted white led they work well
Great vid, and I never knew my FT-736R had that tilt-out feature of the front panel. My LEDs are ok so far, but when I need to, I have an excellent guide... Thanks!
You are one great educator. Thanks.
Thank you for the video Alan. Great piece of info I gleaned from this video was the hinged faceplate on the Yaesu radios. This is a good piece of info because I plan on investing in some older radios and I am a Yaesu fan. :-)
I wish they all made front panels that would tilt out like that, looks like a good way to go.
use LEDs with the inverted conical head, they're perfect for this, or apply silver nail polish on top of a flat head LED, works fine
Thanks, I'll keep that in mind for when the owner wants to convert to LED.
like this. electronics.stackexchange.com/questions/2089/what-is-the-advantage-of-a-straw-hat-inverted-cone-led
+mPD780C1 to be clear on the terminology: straw hat =/= inverted cone, those are to different head types, straw hats are typically shorter with a flatter but still convex lens and as such have a wider diffusion angle than "normal" LEDs
look up your local dollar store around christmas for a cheap source of inverted cone's, the cheapest strings use them, just underdrive them (5-10mA) and they should last forever
I though about these LEDs as well. On the other hand you don't really have to use the top reflecting surface of the light pipe. Its there because with incandescents it was needed. A small SMD LED that just points down into the light pipe would not need it. A round bulb/LED is easier to install though that a LED where you have to build some kind of fixture for first (glueing it to the side of something that fits the hole might be the easiest way).
Sure wish Kenwood had done something similar with the front panel of the TS-940S...although the front panel does tilt forward to get to the S-meter and LCD backlight bulbs the panel can actually fall off if you're not careful. Darn grain of wheat style incandescents! Nice fix Alan...73 - Dino KL0S
The issue with backlighting using LEDs is "viewing angle". A narrow angle almost always results in a spotlight effect. Use a wide angle LED and/or remove the lens. SOMETIMES, that works.
OTOH, an incandescent's yuuge 5X cold-start (inrush) current can be limited to minimize the "Miller-Larson" stress on the filament. Fortunately, for tiny Grain Of Wheat lamps (typically around 25mA running current), the inexpensive LM317L voltage regulator can easily be configured as a current regulator using one resistor. The datasheet shows how. A bonus is, 5% change in running current causes a ≈ 50% change in incandescent lamp life. The caveat is, to get 100% running current, the supply voltage needs to be at least 1.2V above the lamp's rated voltage. So, use 12V lamps instead of 14V lamps.
I made this simple modification to my olde Kenwood TS-120S & TS-130S rigs 'bout a dozen years ago. The lamps stopped burning out. At about 95% running current, I can't tell any decrease in lamp brightness.
Great video. Very informative and well done.
As for the LEDs, I don't understand why people love LEDs so much. In my opinion, they give off an obnoxious glare which the human eye cannot properly focus on. Here in Tokyo, they're converting all street lights and such to LEDs. Terrible idea. I wouldn't be surprised to learn that in the future, there will be a medical health issue related to prolonged exposure to LEDs. They're already discovering adverse affects of these with pregnant women. But that aside, I dislike the 'look' of them compared with the warm glow of incandescents. That's my main reason why I dislike them. The glare and their appearance. Glad you didn't repair this now classic unit with LEDs changing it's original configuration (and degrading its value). As you noted, its design was intended for incandescent lighting making use of silver paint for reflection, etc. To change that would be to in a way, butcher or jury rig the thing to accept the newer lighting format.
As in most antique/classics such as vehicles, furniture, etc. it's always a bad idea to 'upgrade' some component on it to match the present fashion. It destroys the value and original beauty of the thing, dates it to the present and is generally considered destructive to the original engineering and design. That's why you won't see anyone putting LED headlights in their classic Porsche, Triumph or Shelby Mustang. Though there are some who do this, it's a mistake and future owners, users and historians always decry such modifications. But to each his own. ;)
Cheers from Tokyo.
Ty so much for your videos. Between yourself, Buddy, Peter, Paul, Mike and Vern I've learned so much. Something I've never seen, is how to install TMP connectors. I know from warnings to always grab them by the connector, but if a radio comes in with one broken, how to install these TMP coax connectors? Which connectors are sized for which coax? I hear about a crimp tool but no one seems to have one. Not even on eBay lol
Looks like you should be able to take a standard LED, and to combat its forward lighting behaviour, sand its top lightly, and paint the sanded spot white or silver.
I thought about adding backligt for cassete bays in my old Sharp GF-700. I think it should look nice. But... I don't listen tapes since Y2K.
I have a Citizen model BLPL-600 and after I switched over to a different Antenna suddenly see that my meter light(s) is not working now. The meter works perfectly but now have no back light. Does anybody know what kind or brand of bulb my radio takes? Unfortunately I cannot find any info online about this model CB Base Station I just bought. Thanks !!!
The trouble with front panel work is like how many angels dance on a pin head. Just do what you/client likes. The hell with know it alls.
Where did you get the replacement bulbs? Part Number? Thanks for the video; well done.
This video and repair was several years ago. I’m sure I found the replacement bulb part number in the service manual.
At 1:18, to the right of your thumb, there's a white plug, unused. What is that for?
It looks like it was used to connect an optional Voice Synthesizer Module (FVS-1).
Long shot here but my Yaesu powers up but no LED display. Almost appears like nothing on the front panel works except the S-Meter light lol.,
Have you tried plugging in an external 13.8v power supply
But house light bulbs are 100 watts and 120watts but the oils on our fingers don't create thermal stresses on the light bulbs glass but a preamp tube and power tube can get thermal stresses and fracture the glass from our oils on our fingers?
So substituting higher current rating light bulb lamps don't damage or harm the circuit under test that is rated for lower current rating light bulb lamps?
It depends on the equipment.
Is this the same for preamp and power tubes because I seen electronic techs grab the tube glass to pull them out of the circuit and install them in old TV had tubes and old radios used tubes. Also why doesn't a house "lamp bulbs" not have the same glass envelope that is bad for oils on our fingers to cause the temperature of the glass to vary and fracture the glass?
These don’t get hot enough for the thermal stresses to be an issue.
Hi Allan i am using this SD6109 ic in my smps project how can i make a variable duty cycle in this chip
Thanks
Is there anyone outside who knows the diameter of the FT-736R S-meter backlight bulbs. I like to change these bulbs to LEDs. Thanks DG5HB
how about damage to the circuit board that is sourcing the current since the higher current bulb lamp will want to draw more current or overload the lamp output port on the circuit board?
That's usually not the limiting factor.
thanks a lot , great work of yours
as for directional coupler u made earlier does it work on uhf?
if it doesn't any thought on how to make one
Could anybody please let me know what the ratings of these bulbs are?
I searched all over but without success. I need to make sure that ordered replacements will provide sufficient light as even the orginal bulbs make the S-meter barely readable. Thank You!
If you put in a Higher Current bulb/lamp will this damage the circuit because the Higher Current Bulb/lamp would "need more current" in order to light the bulb/lamp which is considered overloading the circuit? Most rating for light bulb lamps tells you the voltage and wattage but they don't tell you much about how much current it needs in order to light the filament in the bulb or lamp. The more filament coils and thicker the filament this is considered a higher current bulb/lamp?
The higher current bulb might cause damage to the plastic parts due to the extra heat.
Is it true that its really bad to put your fingers on a light bulb because the oils on your fingers will cause dead spots and can explode the light bulb? I'm guess its the same for tubes in radios and amplifiers, if you use your fingers on the light bulb and tubes glass envelope it will cause dead spots and crack the glass?
Oils in your fingers can change how the heat is distributed on the glass envelope of a high power light bulb or vacuum tube. If the temperature across the surface of the glass varies too much, it sets up thermal stresses which can fracture the glass.
e um belo equipamento eu tenho um keniwood ts940 mas está precisando da placa do pll aqui no Brasil não encontrei ok
Amigo, percebi que você é brasileiro. Não sei se você tem domínio da língua inglesa porém estou com um projeto de site onde eu traduzo vídeos técnicos de diversos youtubers como w2aew, EEVBlog, Mr Carlson's Lab gratuitamente, o que você acha?
bom dia amigo meu nome e antonio não domino a lingua inglesa mas minha irmã tem min incentivado, e tenho muita vontade de apreder porque sou radioamador gostaria muito de fazer contatos com radioamadores estrangeiros ok a pouco tempo ela não sabia pra onde ia o ingles hoje já e a terceira viajem internacional que ela faz para holanda e de lá vai para varios lugares e não tem dificuldade mas como seria este projeto que voce falou
cool video, thanks :-)
hi i replaced my bulbs with frosted led works great thanks for the videos de zs5mw
SMD leds down each side of the meter would give a much better spread of light. This thing looks like it has footlights and does not fit the general high tech look of the rest of the radio.
I put LEDs in a 767gx and the meter illumination wasn't any better then your bulb replacement. It's a really bad Design.