Battarypack Electribe EMX

Borg · Post by **Borg** » Sat May 17, 2008 3:22 am

@ gmeredith: Yeah I know what you mean, but would it be necessary to test it with a dc adapter? Wouldn't I have to hack another midicable for that? n3ldan make it sound so easy without having to check with a dc adapter.

Borg · Post by **Borg** » Sat May 17, 2008 3:25 am

Ruso wrote:beware, I just had my electribe run on 10.8 v on a really old lap top battery..... it powered up...

then I went out and bought a new lap top battery.... it fried the electribe. Gladly it was a single small component and not the rest of the tribe...

the mistake: I powered it up with a 10.8b 4500mah lap top battery....

too much power. (the idea was to power two electribes at once but I couldn't resist testing it out on one.

so now I'm digging through the damn service manual schematics to find the little part I fried which at this point is quite unrecognizable.

Was it the voltage or the amount of mAh that made the x-tribe blew up?

gmeredith · Post by **gmeredith** » Sat May 17, 2008 3:45 am

but would it be necessary to test it with a dc adapter? Wouldn't I have to hack another midicable for that? n3ldan make it sound so easy without having to check with a dc adapter.

Well, it's not absolutely necessary, but it would save you all the hassle of putting together a battery pack and then find out that it didn't work because it was too small, or too low a voltage etc, and then going and having to buy bigger batteries or more.

Wouldn't I have to hack another midicable for that?

To do the battery pack mod, you'll need to cut in half the MIDI cable anyway - you'll only be using one end. And so the other end could be then made up as a measuring test lead, instead of being tossed.

But in the end, you don't really NEED to measure it - you can take an educated guess, which is what we've all done here, anyway. And I don't reckon we're going to be far off the mark. Especially since Ruso has already put us in the ballpark with his experiments. It 's just that by measuring it you can actually know before spending any money what will do the job, for how long etc. I'm used to doing the measurements because I've got a meter to do it etc. so it's easy for me, but if you don't have the gear then I can see your point.

Cheers, Graham

Borg · Post by **Borg** » Sat May 17, 2008 3:48 am

Well, I thought we already knew it runs off of DC. Ruso have been running his machine on a 15V battery and now recently a laptop battery. It worked, didn't it?

Ruso · Post by **Ruso** » Sat May 17, 2008 3:51 am

gmeredith wrote:Oh - OK. Hmmm... - perhaps more reason to stick with only 2500mAH batteries. And start with a 10.8V pack (9x 1.2V batteries). Ruso - do you think it was the fuse that blew?? - apparently the early X-tribes were recalled because the fuses in them were too low a rating and they were all blowing after a while for no reason at all. Korg said they would put a heavier size fuse in them at no cost...

When you originally tested it on the 15V DC power supply, do you remember its mA rating? Obviously 15V DC didn't kill it then, so perhaps we could find out what current it supplied without blowing it.

Cheers, graham

khehehe my fuse has been bypassed for ages.

as for 15v it was only 850

gmeredith · Post by **gmeredith** » Sat May 17, 2008 3:51 am

Up until just his last few posts, we didn't know specifics. But seeing that he now has mentioned these details about the battery voltage, mAH etc, now we do. So yes, it has now got a lot easier.

850mA at 15V - OK guys, come and get it!

This is an example of how devices pull a lot less current than you think. Ruso had it running off a 15V DC plug pack, rated at 850mA - and it ran. Which means that it would have been pulling LESS than 850mA, or it wouldn't have worked properly.

Let's presume that it was pulling just under 850mA. Then if you had a battery pack that had 850mA capacity batteries, you would theoretically get 1 hour running time (in practice, it would be less than that, because of battery limitations, losses, heat. etc)

So now you can multiply 850mA by however many hours you want to run it for continuously eg. 3 hours =3 x 850 = 2700mAH size batteries approximately. Say 3000mAH for a bit of headroom. This is if it pulls 850mA and was running the plug pack flat out just to run. So it may have been less, which means you'll get even longer on those 2700 batteries.

As for the voltage, Ruso had it running with a 10.8V battery pack. Which I'll bet would have been pulling even less than it was on a 15V plug pack. The lower the voltage, generally the less current it will pull.

Cheers, Graham

Borg · Post by **Borg** » Sat May 17, 2008 3:59 am

Weehaa!

I really can't wait to start building my batterypack/s! I'm going for a two week camp in about a month, and to be able to sit on the lawn with my tribe and jam away would be sweeeet... Where's cash when you need 'em??

Ruso · Post by **Ruso** » Sat May 17, 2008 5:41 am

NONONO it didn't run.... evreything but the tubes ran at 15/850

the old lap top battery was the same as the new one but it was almost dead and could barely hold a charge.

MagpieIndustries · Post by **MagpieIndustries** » Sat May 17, 2008 7:08 am

Ruso wrote:beware, I just had my electribe run on 10.8 v on a really old lap top battery..... it powered up...

then I went out and bought a new lap top battery.... it fried the electribe. Gladly it was a single small component and not the rest of the tribe...

the mistake: I powered it up with a 10.8b 4500mah lap top battery....

too much power.

This doesn't make much sense. A battery with a higher mAh rating will deliver the same current for longer, or more current, but it will not FORCE current into your electribe and blow it. The current draw will be the same irregardless of the mAh rating of the battery, that wil tell you only how lion the battery will last.

It's like drinking out of a one liter bottle, or a two liter bottle. The two liter bottle doesnt make you drink twice as fast.

V=IR or if you rewrite it, V/R=I, and neither V nor R changed, so I remains the same.

so now I'm digging through the damn service manual schematics to find the little part I fried which at this point is quite unrecognizable.

If you shared the schematics with people who understood electronics, we could not only build you a proper battery pack, but perhaps find some cool mods to do to the tribes aswell.

Ruso · Post by **Ruso** » Sat May 17, 2008 3:44 pm

if people asked politely instead of requiring it, I would've shared it. If you really want it try pm.

gmeredith · Post by **gmeredith** » Sun May 18, 2008 10:55 pm

NONONO it didn't run.... evreything but the tubes ran at 15/850

.

Hmm.. back to square 1 (or maybe 2).

Ruso, when you ran it on the old laptop battery, did the tubes work, or only the lights/display?

P.S. the "service manual" was great!!

By the way, about demanding those service manuals: as a person who collects service manuals for all my gear, I know that sometimes you have to BUY them - and they're not cheap. Perhaps you should think about offering Ruso something for a manual that he's spent a lot of money on, instead of expecting it for free from him...

Cheers, Graham

Borg · Post by **Borg** » Mon May 19, 2008 12:30 am

Ruso wrote:NONONO it didn't run.... evreything but the tubes ran at 15/850

the old lap top battery was the same as the new one but it was almost dead and could barely hold a charge.

So how hard is it to bypass the tubes? Or is it something you should avoid and start figuring out a solution for giving it more power instead?

n3ldan · Post by **n3ldan** » Mon May 19, 2008 1:29 am

It's not required that anyone share anything, but most people tend to share things, especially when it costs them nothing to share and it could result in gains for them, such as someone identifying the blown part. If you could replicate food for free would you keep it to yourself or give anyone who wants some a copy?

Also, I am surprised that the battery blew it. Care to chime in on this, graham?

Sorry bought your x-tribe ruso, we may not exactly be friends but it sucks to fry equipment. I suppose that's what fuses are for though XD

I have no reason to own the service manuals for the x-tribes but I would be happy to host them if that's an issue; I know that having such info out there will only result in more cool mods and interest around modifying them.

And Borg, the advantage to graham's battery pack system is that you can charge it without taking the batts out, of course it will take a long time to charge, I don't know a whole lot about charging batteries, but the normal charge time for NiMH AA's is about 7 hours, AFAIK charging faster causes heat issues and that's why the 15 minute chargers have the fans.

gmeredith · Post by **gmeredith** » Mon May 19, 2008 2:19 am

Hi n3ldan:

I am surprised that the battery blew it. Care to chime in on this, graham?

Still trying to figure it out. As Ruso's doesn't have a fuse, it's hard to say if it was a result of too much current, or too much voltage in the new battery (although both are related). I would have thought that the EMX would have had more headroom for voltage differences than that. Definitely, if he was using an old laptop battery before the blow, which might not have been in peak condition, it may not have been putting out as much voltage under load as a new one could, maybe.

Ruso:

What batteries or power adapters did you get the EMX to both light up the display AND run the valves? Was this the 10V power tools battery that you mentioned before?

the advantage to graham's battery pack system is that you can charge it without taking the batts out

Yes. And also that it means you can use your X-tribe WHILE its charging, which is cool when you suddenly get hit with some songwriting inspiration, and you've only just put the batteries on charge

Cheers, Graham

gmeredith · Post by **gmeredith** » Tue May 20, 2008 2:25 am

OK, I've just had a chance to look at the full schematics.

They indicate that parts of it can run at up to +15V DC and -15V DC, 500mA (the analog section). The tubes run at +6V DC, 640mA EACH (1280mA total). The logic circuits run at +5V and +3.3V DC, about 1000mA in total, the CPU at +1.8V DC 500mA.

It would appear that it is designed to run happily at up to 15V DC, so 12V should be OK. Each part has its own voltage regulator to feed it the correct voltage. It will need more than the 850mA of Ruso's power pack he used, though - in total it may need about 2000-3000mA.

The thing that concerns me is that part of the analog circuit needs -15V DC. This means that you won't get audio without the -V component (i.e. a split rail power supply). Unless Ruso has managed to trick it somehow with his single battery back, or unless we've totally misunderstood him and that he's been saying that he got it to run off batteries, but only partly - no audio. Is that correct, Ruso? What was your trick, if otherwise?

Cheers, graham