Marantz 4240 Lamp replacement

[stratmaster4]

What kind of lamps are in my 4240 ? I have all the electronics to convert to LED ready to go but I fear that the lamps in it are the kind that are like fuses. Can anyone confirm what kind they are?

I really want to replace the lamps before I get back to school as thats the only thing left to do before its fully restored.

 

[Rasputin47]

The lamps behind the dial and meters are 8V 200ma fuse lamps, and bi-bins for the function lamps.

 

[petehall347]

you can buy ready made led fuse lamps or you could make your own . i think they have 3 smd led.s in each one

 

[stratmaster4]

you can buy ready made led fuse lamps or you could make your own . i think they have 3 smd led.s in each one

The ready made ones are so expensive. I am fairly skilled with a soldering iron so I think I will make my own.

What size fuses are the same size as the lamp?

Should I use SMD LEDs and go point to point or do you think I can fit 3MM LEDs inside the fuse enclosures?

 

[Gum Parker]

I melt open regular Buss fuses, the "Fuse bulbs" are not candidates for this. Next, punch holes in their caps. I then put 2- 3mm LEDs in them with a 220 Ohm 1/4 watt resistor inbetween. Then I put the long end lead through one cap & solder. Then the short lead through the other. Liquid electrical tape helps seal the LED Butts.
Voila! a 2-LED fuse style buss bulb.

You can vary the resistor Ohms, I find people use a range between 100 and 220 from what research I've done.

The 3mm LEDs may have to be trimmed of their base "lip" for best fit.

Covering the top 2/3 of the LED with super glue and quickly dunking them in baking soda quickly -will coat them in white & help disperse the light better.

The light will be a different blue shade -for an original look, use an amber filter gel.

 

[stratmaster4]

I melt open regular Buss fuses, the "Fuse bulbs" are not candidates for this. Next, punch holes in their caps. I then put 2- 3mm LEDs in them with a 220 Ohm 1/4 watt resistor inbetween. Then I put the long end lead through one cap & solder. Then the short lead through the other. Liquid electrical tape helps seal the LED Butts.
Voila! a 2-LED fuse style buss bulb.

You can vary the resistor Ohms, I find people use a range between 100 and 220 from what research I've done.

The 3mm LEDs may have to be trimmed of their base "lip" for best fit.

Covering the top 2/3 of the LED with super glue and quickly dunking them in baking soda quickly -will coat them in white & help disperse the light better.

The light will be a different blue shade -for an original look, use an amber filter gel.

Could you possibly explain all this better and include pictures?

 

[stratmaster4]

Could you possibly explain all this better and include pictures?

Also what sort of amber filter gel should I use?

EDIT:
And what size fuses should I order to put these assemblies in?
Should I have diodes and Caps like all the other amps I have done?

 

[yostie70]

Don't forget about the search function of the forums. This is just the first one I came across regarding your question. http://www.audiokarma.org/forums/showthread.php?t=351081&highlight=leds
I'm sure there are a few more if you look.

 

[Switchblade]

They are not expensive considering how long LEDs last and the grief it saves. Check with seller whsh94a on Ebay. I've bought a bunch already (at least 7 sets) and they are great! Used by a lot of the top restorers here on AK. They snap right into the original lamp holders. Worth EVERY penny!

 

[Gum Parker]

Everything I learned to repair old Marantz receivers- I learned pretty much here in these forums. In one years time, I have learned to repair these receivers and how to make these LED replacement fuse lamps.
Start by removing an existing fuse bulb from your receiver - that's your size.
You have a great learning resource here to educate yourself. I offer only one way to make these. Reverse engineering my methods could give you an even better solution.
Try, fail, try again, improve it, make it work best for you. Have fun & a good magnifying glass.