Getting main armament and headlight working

Discuss the good old Heng Long electronics here, whether its mods on them or anything else, it goes here!
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abramsky
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Re: Getting main armament and headlight working

Post by abramsky »

You're right Jofaur. Only a few LEDs colours (around blue and UV) go beyond 3.3V, but to be precise it is worth mentioning.
This is true with reverse polarity, but since I looked here I have read so many "dramatic" posts about damaged MFUs (most often due to cable connection errors by the user) that it is worth mentioning how to properly test and diagnose problems with your electronics. As we both mentioned - even the cheapest multimeter is MUST HAVE in every RC workshop.
Best wishes :)
Jofaur86
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Re: Getting main armament and headlight working

Post by Jofaur86 »

:D or am I surprised? this is why if one does not make a short circuit on an output, for what the MFU would burn out? following connection Led bad voltage? but not know everything. At one time I had found this for an RX 18 in 2.4 ghz
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SimonCornes
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Re: Getting main armament and headlight working

Post by SimonCornes »

I’ve got the led out. It’s dead!! It’s a 3mm and looks orange. I’m replacing it with a ‘warm white’ 3v 3mm LED - cost 99p!! I think that might be for 10 as well but I’m never too sure with eBay! Anyway I only want 1 and it’s cost 99p posted so I’m not complaining!!
I’ve also been testing various leds using a thing called a ‘versatile power supply unit’ that I built last century- probably late 80’s, early 90’s and I can turn the voltage up from zero with a rotary reostat and 3v is more than enough!
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tankme
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Re: Getting main armament and headlight working

Post by tankme »

I bought a variety of LED replacements of all kinds to have around and do builds with after frying all of them in my ZTZ-99 connecting them to the TCB. Didn't read that it sends full voltage to the LEDs unlike other boards. That was a nasty smell that lingered. I bought only two types of resisters for simplicity sake and put them inline and everything is great now. The colored LEDs seem to use less voltage on average and the white regardless of size (3mm or 5mm) are higher. LEDs are cheap which is why I picked them up in larger lots. That way I'm not waiting on shipping and got them from a US supplier. I may have paid a little more, but at least the money didn't go DIRECTLY to China. Same place had fiber optic cable really cheap. Ebay wanted a couple of bucks for less than a foot of fiber optic rod. I paid a couple of bucks and got 10ft and in several sizes to minimize shipping costs. More than enough to last me a lifetime of tanking.
Derek
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Tiger6
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Re: Getting main armament and headlight working

Post by Tiger6 »

SimonCornes wrote:I’ve got the led out. It’s dead!! It’s a 3mm and looks orange.
I seem to recall mine were some kind of greenish hue - not sure which is worse :crazy: I'll have to get my finger out and finish / refurb both of mine, I haven't touched either of them in nearly 10 years :/
SimonCornes
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Re: Getting main armament and headlight working

Post by SimonCornes »

Tiger6 wrote:
SimonCornes wrote:I’ve got the led out. It’s dead!! It’s a 3mm and looks orange.
I seem to recall mine were some kind of greenish hue - not sure which is worse :crazy: I'll have to get my finger out and finish / refurb both of mine, I haven't touched either of them in nearly 10 years :/
The light in the WSN T34 is green! But as the voltage goes up it starts to go a bit more orange - I stopped before I blew it!

But you real must get a grip on your brace of Kings!! :haha:
Tiger6
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Re: Getting main armament and headlight working

Post by Tiger6 »

I decided several years ago that the collection was getting out of control and I would concentrate on modelling 1st SS Pz Div and US 4th AD at the Battle of the Bulge (people that know me, know how well that went as a population control measure :/ ), and as both have zimmerit (and one got fitted with a Porsche turret) they aren't suitable for portraying KG Peiper's King Tiger's.

I have at least collected Tamiya DMD's and MF's for them, so the most expensive parts are already set aside waiting for me to get the urge to finish them :haha:
SimonCornes
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Re: Getting main armament and headlight working

Post by SimonCornes »

EricTaylor55 wrote:Limiting resistors when turning on LEDs is not the most effective but the easiest and cheapest solution to limit the current within permissible limits.
Any suggestions on resistor values?
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tankme
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Re: Getting main armament and headlight working

Post by tankme »

I've been using a 370 ohm resistor for 3mm and 5mm LEDs using standard batteries like the 7.2/7.4V. The resistance needed changes with the voltage. That was what was recommended by the company I got my LEDs from. The manufacturer of the LEDs should have some recommendations to resistor values.
Derek
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SimonCornes
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Re: Getting main armament and headlight working

Post by SimonCornes »

tankme wrote:I've been using a 370 ohm resistor for 3mm and 5mm LEDs using standard batteries like the 7.2/7.4V. The resistance needed changes with the voltage. That was what was recommended by the company I got my LEDs from. The manufacturer of the LEDs should have some recommendations to resistor values.
Thank you. I’ve used a variable resistor but these things get ridiculously warm whereas standard resistors are always cool. I tend to use only 2-3 volts and I use a variable resistor like a volume control!!
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