Sansui 7070 tuner pointer bulb...led replacement?

AtomicLP

AtomicLP

New Member
Hello, I just picked up a beautiful Sansui 7070. I plan on updating the fuse style lamps to warm white LED's, as I did to my 5050 (looks great and original). Unfortunately the orange pointer lamp on the 7070 is burnt out and I need to replace it.

From the schematic I can see it's a 6.3V 75mA 3mm lamp. Has anyone upgraded to an LED? Looking at an 8v I saw on vintage electronics.net. The pointer glows orange, is another slip cover required? Anyone have experience with the led swap? I'd like to maintain it orange.Thanks
 
Register to hide this ad
AtomicLP said:
Hello, I just picked up a beautiful Sansui 7070. I plan on updating the fuse style lamps to warm white LED's, as I did to my 5050 (looks great and original). Unfortunately the orange pointer lamp on the 7070 is burnt out and I need to replace it.

From the schematic I can see it's a 6.3V 75mA 3mm lamp. Has anyone upgraded to an LED? Looking at an 8v I saw on vintage electronics.net. The pointer glows orange, is another slip cover required? Anyone have experience with the led swap? I'd like to maintain it orange.Thanks
Click to expand...


I replaced the lamps in my 9090, and I didn't even notice there was a lamp for the pointer! I also went with the warm white LEDs. I actually would like them to be brighter, but the do the job. Unless they are pointed exactly perfect, you get dim spots on your dial. if you could post a picture when you replace it, i'd like to see the position. I've since closed mine back up and she's in use, so seeing exactly how you replace it will help me replace mine quickly.
 
You can use a 3mm LED to replace the dial pointer. All LEDs need a current limiting resistor in series with the LED. The LED will fail without it. You can wire the resistor anywhere in the LED circuit. The pointer bulb on the 9090 already has a 10 ohm resistor in the circuit. It's on the circuit board for the dial lamps. You need roughly 250 ohms resistance to protect a typical little 3mm LED.

- Pete
 
Thanks

Ordered a 3mm pre-wired amber LED to use for the pointer. I'll be posting pictures of a comparison between cool-white fuse VS. warm-white fuse LED's for the tuner section and meter when they arrive in the mail.
 
There is not a lot of room in the top of the pointer. If they mounted the current limiting resistor too close to the LED, you may not be able to install it. It's a tight fit for just the bulb.

- Pete
 
I see that the original bulb wires go under the tuner cable. I think it would be easiest to install the new light over top, cutting and leaving in place the old wires. I'll have to wait to get the light to make a decision on that.
 
poor picture but it shows how I did it. The resistor is in the tubing which supports the supply wires. The shrink sleeving is just super-glued to the carriage. Note that the lamp is much less white in the flesh, more orange/amber



upload_2016-11-15_17-42-49.png led lights 003.JPG
 
DougBrewster said:
poor picture but it shows how I did it. The resistor is in the tubing which supports the supply wires. The shrink sleeving is just super-glued to the carriage. Note that the lamp is much less white in the flesh, more orange/amber
Click to expand...

Looks great! thanks for posting the picture. I want to install it a similar way, but since I'm going pre-wired the resistor is already in place so I'll just have to put a bend in. Did you use a warm or cool white LED for the pointer? Is the amber close to original? I ordered a warm & cool and and an amber 3mm led to test out.

Those power meters look sweet, did you use a cool white LED in there? I'm contemplating doing the same. I think the white hue versus the original greenish yellow glow gives the 7070 a nice update.
 
I did an an amber led replacement on a 5000, and I placed the resistor right at the led. Worked fine,





Cheers

John
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom