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Evenly illuminated Marantz dial plate and meter with LED

G

golfaja

New Member
Just an amateur work, but i am very pleased with the result.

I converted 7,2v ac to dc, added one 16v,1000mF capacitor to prevent leds from flickering.
Then soldered 2 led in series and two pairs like that in a parallel in order to get a four led combination fit one bulb place. Also added a 33 Ohm resistor for each 4 led to lower the current flow a little.
(If I am not mistaken 1led=3v,20mA, and 4led in this series/parallel combination=6v,80mA)

To get even-lighted meters / scale just bend outer leds a little, toward the gaps...and placed two little pieces of mirror under to reflect the light upwards.

In a dial pointer placed one orange led (also with dc current, this time 220R resistor and a small cap).

Don`t have all the steps photographed but these will do the job.
Hope it will help anyone who wants to do something similar...
 

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Nice job! :thmbsp: I would be careful of too large of a capacitor on the lamp winding. It's also not generally a good idea to parallel leds. Did you try using the AC and reversing one of the parallel pair? This eliminates flicker but at a slightly reduced brigtness. Just some thoughts. Very nice work.
 
Well, thanks !
I`m glad you all liked this.

I didn`t try AC with reversed led in parallel,...,didn`t even know that would work (remove flicker), ...this is all new to me, i gathered info on how to do this from the internet, and had just a little basic knowledge, good will and soldering iron.

Thanks for the info justw! If something goes wrong with my "handywork" I`ll try that next...

I wonder what damage too large cap can do?
Why it is not recommended to put leds in parallel?

This 1000mF cap is "feeding" 28 leds and when i power down receiver they turn off almost instantly ( there is very, very little power reserve left in the cap - you could say none )
I`ve read posts and seen some pics in one other forum where 6 leds like mine were powered with "only" 330mF. So i took something approximately 3 times that value...
 
The only thing with large caps is when the receiver is powered up the capacitor takes a "surge" current as it charges. I'm not an engineer but, I am not sure the winding for the lamp voltge can handle a lot of surge current. You really don't need a huge one as all it does is help filter some of the ac component in the DC.
As for paralleling LEDs, they are not perfect and one will try to draw a bit more current than the other and yet the voltage across them is equal. I suspect worse case is one will open up from excessive current.
Here's a good presentation someone put together that has some good info in it:

http://www.gizmology.net/LEDs.htm
 
After your first post justw, I did a little search and found a few sites explaining everything you were talking about.

Now I know the lacks of my design and am willing to correct it, but after this one eventually fails. I hope they`ll last anyway because current flow through led is limited to its 90% of nominal mA and leds do have some small tolerance...

Best regards from Golfaja !

Here is the picture showing how receiver looked when I got it !
 

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here is a pic of my 2245 with the LED upgrade from AK's whsh93a...
the look is amazing!

Vincent
 
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Thats great Steelman! I would do the same thing, but I live in Novi Sad ( that is in Europe, Serbia ) so ordering something from USA is way too long and expencive.
Many times even orders from Germany (ebay) didn`t arrive and i payd them.
This adventure of mine with leds costed me only 10 euros :D and teached myself somethig new along the way...
 
Excellent work Golfaja! Would you like/mind if I decide in some future to do some modes on mine 2250B also? :)

Hello from Belgrade! :)
 
golfaja,
Very Nice for self taught!!! :thmbsp: I tried to look up info on LED conversions but, it just made my head hurt :twak:

Vincent
 
Gidra, not at all !
I`ll be glad to help. I have burned out couple of leds during the process (of learning) and will tell you what works best. Some of my seriall/parallel wiring is not a good solution...will keep you informed on changes and corrections i am about to do ...thanks to justw...eventually I will do everythig right...
 
Very nicely done! What an enormous contrast between the "before" and "after" pics. Reading the thread, it seems there is some controversy about the best approach to doing this. It would be nice to know the BEST method, for an optimal balance between light quality and longevity (with safety). I think I'll try something like this the next time I refurbish a Marantz receiver. Thanks for sharing this. I love the way stuff like this comes up on this forum; what a great resource!
 
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