FYI- Lot of used 616's on eBay

**Darth_DevilGuy** · 08-02-2008, 12:38 PM

all I know is I burned out the resistor responsible for amping the speaker on mine with a 4AAA pack from the store, I have to go search the thread out but I believe it can be fixed by adding a transistor to the circuit.

**Novastar** · 08-02-2008, 02:06 PM

4AAA Alkaline = 6v... (1.5 x 4 = 6)

So... it's not surprising. The very MAXIMUM most any MRFX board (616 or otherwise) can handle is 6v--if you're lucky. Normally I don't get snippy about this sort of thing, but... this has been mentioned in about FIVE different ways over a series of different threads just in the past few months, so... everyone get that through your thick skulls:

MRFX (of any kind) @ 7.2v = Furrget it. Not a chance. Unh-anh! No can do, sister. Hasta la don't friggin' do that.
MRFX (of any kind) @ 6v = you are pushing your luck... but it might work 100% fine for years, months, or days
MRFX (of any kind) @ 5v = Perfectly fine
MRFX (of any kind) @ 4.5v or even 3.6v = obviously just fine

Personally, my guess would be that the 616s are LESS apt to survive 6v vs. the "older" MRs... probably due to even LOWER quality parts being used on the 616s. I'm not certain of that, but... I'd say that's a safe guess if you had to bet which one was made to be less expensive... gee duh ya think? The one with the plastic parts??

But anyhow. The 616 can "spit out" ~1A if you want it to do so. Although it wouldn't do this without modification, since it only can be set to Red, Green or Blue--and nothing in between.

**Darth_DevilGuy** · 08-02-2008, 04:37 PM

I think their tolerances may be lower, after doing some inspection on the one I burned I think that they used cheaper parts in the construction, now that I have several in my possession I can say that the tolerances on the other parts are looser than on standard MR models, says something about their production quality, nonetheless they make for excellent sound cards for sabers, so long as one is careful with them.

**strengthofrage** · 08-03-2008, 08:23 AM

I have used 2 of these so far, both powered by 4AAA packs from the shop. They work fine. I believe Armonfire did the same. It is the absolute max you can use, though I wouldn't try using that setup if you are using the board to drive your LED. The setups we use are the dual 700mA puck for the LED and the sound separate.

**amichaels** · 08-03-2008, 11:26 AM

Any chance you could post a pic of the guts? I'd like to see how it's wired up and I'm pretty new to wiring things.

Edit- I think I found one of the wiring threads that shows what I'm looking for. :P

**Arm on Fire** · 08-03-2008, 01:24 PM

I too have used 2 so far with 4aaa 6v packs with no problems.

I do agree with Nova in that the 6v are pushing the limits and possibly shortening the life of these boards and causing random problems.

One thing I found when I put in the diode to solve my no powerdown sound problem was the diode dropped the voltage slightly, so it not only kept voltage from back washing it also helps keep the voltage just below the 6v limit.

**Obi-Dar Ke-Gnomie** · 08-03-2008, 01:37 PM

I missed that. Where did you put a diode?

**Novastar** · 08-03-2008, 02:36 PM

The Zener Diode, right Arm?

Right--a little extra resistance and sometimes the "6v" can be dropped down to something that will work better for the board's survival.

As it is... we all must remember:

"6v" or "5v" or "4.5v" is *NOT* as specific as we think--at least initially when putting in fresh battery setups. 6v is more like 6.4v. 4.5v is more like 4.7v or 4.8v. In general, if you want "perfect" voltage or specific voltage for the MR, I might recommend the following (for pushing the board's limits):

* Some kind of 6v solution
* Immediately following the cells, a 6v regulator

Sounds weird I know, but... this will mean that the board should NEVER even get 6.1v... or 6.2v. Which is probably a good thing.

You could even wire up 7.2v Li-Ion and then use the regulator to dumb it down. But, taking a more "true" 8.4v (from the 7.2v) to 6v is QUITE a bit of heat for the regulator to dissipate, so... mise en garde!!!