Korg Forums

Hi all,

I posted this up on another electribe forum, I thought I'd put it here also, in case anyone is interested in this.

I know that there is an external battery pack mod that you can do for the early electribes, but has anyone done a mod of installing a rechargeable battery pack INSIDE an electribe? I thought I'd ask before I "reinvent the wheel" again, in case someone has already done this.

I'm going to try it on my ES-1, and make up a DIY guide for the mod, if there hasn't been one written already. After opening it up and doing some sourcing of parts, I've figured out that I can fit 8x AAA NI-MH batteries in it, to give it a 9.6V battery pack. I measured up the space for AA batteries, but there is not quite enough space. Using AAA's enables me to fit them virtually anywhere in the back of the ES-1 casing. It looks like a simple job.

The largest capacity AAA battery I have found so far is a 1200mAH battery. I measured the current drawn by my ES-1 and found that it draws 230mA maximum while playing at full volume, powered off its 9V DC plug pack. That means that a 1200mAH battery pack will power the ES-1 for about 4 hours continuously. There may possibly be enough room to mount 2 battery packs in parallel to give a 2400mAH pack, which will
give you about 8 hours continuous use.

It will have a separate charging socket in the side of the ES-1, and you can use the ES-1 while it's charging the batteries if you plug your electribe power pack, which will double as the charger, into this socket. Alternatively, you could have the battery hooked up so that it uses the SAME socket as the power pack, and dispense with installing the extra charging socket. The advantage of the extra charging socket is that when the batteries are fully charged, you simply put it in the normal power socket when you want to run it off mains power, and the batteries won't continue to charge and so not be overcharged.

I'll let you know how it goes, once I get hold of the batteries and try it. It **should** work with the other electribes (but not the X-tribes), but I can't say for sure because I don't know if there is the same space layout in the other electribes as the ES-1.

Anyone interested in this? It should be an easy mod, probably cost about $30 all up in parts.

Cheers, Graham

Souds great, but why won't it work on EMX1, you think?

tp_zoveel wrote:Souds great, but why won't it work on EMX1, you think?

Because the EMX1 needs an AC power supply.

because it has a different power supply and it has tubes.

Yes, the X-tribes power supply works completely differently - as we discovered in the "EMX battery pack" thread.

I forgot to mention that with this internal battery mod, you can also use it to power other 9V DC pieces of equipment at the same time, such as a guitar pedal, etc. So, in essence, your electribe becomes a portable battery pack for other equipment.

All you do is just make up a DC power cable with 2 plugs on each end, and just plug one end of the cable into the electribe's charging socket, and the other end into your other machine that runs off 9V DC - such as another electribe!! Be mindful that it will drain your batteries twice as fast, though, if you use another electribe or high drain device. Guitar pedals will pull almost no power from it and so will barely affect it. Also be mindful of the polarity of the cable for the other device - you may have to make up 2 cables - one for "outer ring +" and another one for "outer ring -" , for some equipment such as Yamaha, that have reverse polarity power requirements.

Cheers, graham

Hi guys,

Ok, I've got it happening.

I've sucessfully modified my ES-1 to have an internal rechargeable battery pack. I've written up an illustrated DIY guide , for anyone interested in trying it with their Electribe mk 1 or 2. It's in the Yahoo Electribe group, in the FILES section (you have to join as a member, though to access the FILES section)

http://launch.groups.yahoo.com/group/electribe/

There is also a video clip of it in action there as well.

Although it's written for the ES-1, it may also be relevant for the other Electribes (not X-tribes, though), so long as there is the space in the casing for it.

This has worked out really well. Depending on which batteries you choose, you could get up to 10 hours continuous use out of a charge. I chose cheap, small AAA 900mAH rechargeables that were locally available, and I get over three and a half hours out of them continuously. Other batteries that I suggest in the guide will give a lot longer.

You can also use the modded Electribe itself as a portable battery pack to power other 9V DC equipment, simply by switching a switch and plugging in a DC extension cable into the charging socket to a guitar pedal, drum machine, or even another Electribe!

It also uses the standard Electribe DC 9V power pack as the charger, so there's no need to buy a separate charger. It will charge a battery pack the same as mine in about 10 hours. You can also use the Electribe WHILE CHARGING the batteries.

The mod also features reverse polarity protection for the battery pack, in case another, incorrect polarity power pack is plugged into the charging socket.

Cheers, graham

i just did this with my EM-1

but with 16 gumstick batteries

its charging now (hopefully) and ill test it out in a while

i couldnt find my multi meter so lets hope all the solders were good enough

for anyone else attempting this rough sand paper might make the solder stick better to the batteries

i might have to go back in

Hey, Zalo,

Thanks for giving it a go! How did the 16 gumstick batteries fit? I presume you have 2 banks of 8 gumsticks, with the 2 banks wired parallel to each other. Was there major hassle? That's a lot of batteries - that should go forever (well, nearly hehe!)

And thanks for the soldering tip - I've AAA's in battery holders in mine at the moment, so I didn't have the soldering problem, but I'm on the lookout for some cheap gumsticks to upgrade. Where did you get them from? Ebay? What price did you get them for?

Be aware that those gumstick batteries are pretty high capacity, so you'll need a looooonnng charging time to get them completely charged - a couple of days, especially if you're using the EM1 power pack

Cheers, Graham

well i went to try it out being about 10 hours later to see if it would work

it should turn on even with a partial charge for a little bit

nothing happened

so i plugged the power supply back in

still didnt turn on (great i killed my em1)

i plugged the power adapter into my K61P since its the same adapter

it didnt turn on

so

in the last 10 hours while i was away my korg power adapter died on me

now i have to go find another adapter

so tomorrow between work and band practice, im going to run by the store and grab one of those multi adapter

but i still dont understand the fast charging

on the power stream page it gives no mention of voltage increase but in your example you are using 12 vdc instead of 9 vdc

and with the original korg it is 600 mA but you say that it only charges at 80 mA

how do you increase the mA then?

to answer your questions. they fit rather easily, no real hassle. i got them from ebay 70 dollars after shipping

ill post a picture tomorrow

OK, there seems like you have a short in your connectors or wiring, or you've wired up your connector in reverse polarity. The Korg power pack should not have blown with these batteries wired correctly.

I would say that it probably blew within the first couple of minutes of plugging it in, and that the power jack may have been wired perhaps around the wrong way or shorting somewhere - there are 3 solder pins on the jack, right? 2 of these connect to the same terminal (= short out!!) and 1 connects to the ground. Get it wrong and sszzziittz.

Which is why a multimeter is way the safe way of testing it.

The EM1 should be ok as it is reverse polarity protected internally.

Let's try and work backwards. Forgive me if I explain this really simply as I do it, you may already have a reasonable idea in what you're doing, but I'll presume its your first time unless you mention otherwise.

Even without charging your battery pack for the first time, the batteries will have enough residual power to power up the EM1 and test it. So without plugging in any power pack, you should have been able to switch it on and test it for a bit straight after completing the hookup. Since you mentioned you switched it on and there was nothing, it sounds like your battery pack is reverse wired to the EM1. Unhook your battery pack from the EM1 and test your pack outside of it.

You could have also made up your battery pack wrong. They could be shorting each other out, which would have also shorted out the power pack.

How did you wire them up?

You should have 2 separate "packs" made up, in your case of 16 batteries - 2 packs of 8 batteries. .

In a single "pack", the 8 batteries should be wired in series: - to + terminals joined in a line etc. This will give about 10V.

Test out each single pack on the EM1 at a time, before hooking the 2 packs together. Forget about the charging socket for the moment. Disconnect it.

Start from the beginning.
Solder the - terminal of an 8-pack to the place on the EM1 board shown in the guide, then the + terminal of the pack to the correct place also. Don't install the 2nd pack yet.
Now switch the EM1 on. If your batteries are all facing the right way, the machine should work. If so, OK then.

Make up your other pack exactly the same way. Pull the other one out and put the 2nd one in and test it. OK? Now lets hook them both up.

The 2 packs must be hooked up in PARALLEL to each other. Hook them up to exactly the same places on the EM1 board as the other one: + wire to + wire, - wire to - wire, so the 2 packs are in Parallel. If you see a big spark when you connect the 2 packs together, you've got them around the wrong way to each other.

This is the rule: when you hook up batteries in SERIES (as inside each battery pack with the 8 batteries) the + terminal goes against the - terminal of the next battery in a line or chain. Never should a + terminal ever touch a + terminal, or a - touch a - terminal when in series.

Now, when the 2 packs are hooked together in PARALLEL, the rule is the opposite: + terminal always goes to the + terminal, - terminal goes to - terminal. Never + to - in this case.

Once you've got both packs hooked up and soldered in, and the unit is working, now you can deal with the charging socket.

the original korg it is 600 mA but you say that it only charges at 80 mA

That's what the power pack is CAPABLE of, not what it does while hooked to a particular appliance. To MY batteries, it will be about 80mA (but to YOUR battery pack, probably double this or more - you've got 2 packs - twice the drain).

but i still dont understand the fast charging .... how do you increase the mA then?

The website didn't mention it because it was kind of "presumed knowledge".

The short answer is you increase it by increasing the voltage of the power pack. The Korg pack is rated at 9V, 600mA in capability - but if you connect nothing to the power pack and switch it on, it will read about 12V. (and of course, it will be providing a current of 0mA). It has to, otherwise if it were less than 9.6V (your battery pack) it wouldn't charge it. When it is hooked up to YOUR battery pack, it drops down to about 10V, and puts out about 200mA (guessing for your case).

To get it to fast charge, buy a multi voltage power pack, say between 6-12V, 1000mA. if you switched it to the "9V" position to start with, and then you measured it with a multimeter, you would probably read about 14V. Connect it to the battery pack and it will drop down to 10V and give about 200-300mA current. Switching it to the "12V" position and it would probably read about 18V. Connect it to the battery pack and it will drop down to 10V and give about 500mA or more current. That's just a guess. If you do buy one of these, start with the 7.5V position (it will still be putting out about 10V on a meter) and feel the temperature of the charger every now and then. If it's still cold after half an hour, it's not working hard - knock it up to the 9V position and check it again after a short while. If it only gets slightly warm, hit it up to the 12V position, and check it frequently. If it gets too hot, it's charging hard, so knock it back to the 9V pos. Once your familiar with it, you'll know which is the maximun safe setting for the charger. Let it charge but feel the back of the em1 a while to see that the batteries don't overcharge at this setting. When they start to get warm, they're charged.

Cheers, Graham

P.S. Check to see whether your Korg power supply can be opened up. It may have a fuse in it you can replace.

Cheers, Graham

didnt realize ac/dc converters worked like that

well. the dc socket i bought was a 2 pin so there is no way i wired that up wrong

i played with the electribe for a while before connecting the battery packs

so i know that everything before the battery packs is working fine

ive taken some electronics classes and some physics so the series and parallel are all old hat

i am going to hunt down my multimeter and test the battery packs tonight but i dont understand where a short could be in them

i could understand them just not charging because of a bad connection

sorry to split this into two posts i realized i had to go to work

and now im on my phone haha

while soldering i take a very careful approach and do all the positive connections at once then do all the negatives so i dont accidently cross wires

so i dont see a shorting problem in any of the wiring

there is a little bare metal on the dc socket near a solder on the board which worries me a little and ill tape up when i get home

i guess its time to desolder and pull out the battery packs and start things up again

I'm glad you know some electronics, that makes it easier.

Hmm. Does the board pic of my ES-1 in the guide look the same on the track side as your EM1, around the area where the batteries connect to the board? I've made that assumption when I wrote the guide for the ES-1. I hope its correct, otherwise there may be a problem.

Did you get a new power pack yet and try it on the EM1 (with the batteries pulled out) to see if its ok? I hope so, I very much doubt it will have been damaged.

Just to check: although the socket you bought was 2-pin, did you make the outer ring terminal the +ve connection to the board/battery? The Korg power pack is outer ring +. If you had it the other way on the socket, you can fry your power pack.

Cheers, graham

well i took apart my battery packs and realized that none of the negative connections actually took

so i sanded them with medium grit metal sand paper and resoldered

now i can get about 8 volts out of the pack sitting by itself uncharged (1 volt a cell seems like a standard for dead batteries)

i got the new power pack and it works fine (even though it makes my k61p act weird)

here comes the problem when i solder the one battery pack in and measure at the connection points on the board i only get about 1-1.5 volts

now im thinking i should solder the battery packs directly to the board connection points as to bypass all the extra hassle and possible bad solders