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Roland MKS-50 battery replacement
Old 17th January 2010
  #1
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rids's Avatar
 
🎧 15 years
Roland MKS-50 battery replacement

Once I received my MKS50 and powered it up, the screen said 'replace battery'. I'm wondeing how easy this is and what the cost of this is going to be. I'm going to pop it open tomorrow, but was wondering if anyone has had experience with this. Not sure what kind of battery it needs since the manual doesn't seem to explain anything besides to take it to a Roland tech.

My patches on the unit are all scrambled. The names for them are all random letters and there is either low volume or no sound at all on the patches. The weirdest thing is, if I press the 'up' button on the MKS, it plays a note. If I press a note on my midi keyboard, it does nothing, even though I can verify that the MKS green light, lights up and is receiving midi.
Old 17th January 2010
  #2
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golden beers's Avatar
 
2 Reviews written
🎧 10 years
Quote:
Originally Posted by rids ➑️
Once I received my MKS50 and powered it up, the screen said 'replace battery'. I'm wondeing how easy this is and what the cost of this is going to be. I'm going to pop it open tomorrow, but was wondering if anyone has had experience with this. Not sure what kind of battery it needs since the manual doesn't seem to explain anything besides to take it to a Roland tech.

My patches on the unit are all scrambled. The names for them are all random letters and there is either low volume or no sound at all on the patches. The weirdest thing is, if I press the 'up' button on the MKS, it plays a note. If I press a note on my midi keyboard, it does nothing, even though I can verify that the MKS green light, lights up and is receiving midi.

it probably needs to have a good voltage in the memory for the boot sequence to work. if it's not booting properly you could get all kinds of weirdness. don't worry about it's odd behaviours until you replace the battery.
Old 17th January 2010 | Show parent
  #3
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flat's Avatar
 
🎧 10 years
I posted this thread on another forum sometime back. Has battery info and some photos. The info on @Juno 2 (keyboard version of MKS-50) as follows:

Model of Synth: Roland Alpha Juno 2

Battery Type: CR2032

Info:

The original battery has legs soldered to the board. You can replace it with a similarly-leggy CR2032, or do as I did and install a battery holder and insert a normal CR2032 battery in it's place.
Old 17th January 2010
  #4
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Don Solaris's Avatar
 
4 Reviews written
🎧 10 years
My MKS-50 battery died...

Quote:
Originally Posted by rids ➑️
Once I received my MKS50 and powered it up, the screen said 'replace battery'. I'm wondeing how easy this is and what the cost of this is going to be. I'm going to pop it open tomorrow, but was wondering if anyone has had experience with this. Not sure what kind of battery it needs since the manual doesn't seem to explain anything besides to take it to a Roland tech.
Open the unit so that you can reach the bottom of the PCB. Unsolder the battery. Check the voltage and size (exact type is irrelevant) then go to store with it.

Buy the one with the same voltage and size. If they have machine there to add leads to the battery please tell them to do so. If not, then as Flat Earth suggested, buy a battery holder there that will fit the same battery. Battery holder is a better solution anyway. DON'T try to solder the battery itself (if you don't have a holder) to provide it with leads. It might explode! Rather go to other store until you find the matching holder.

Take care when inserting the battery into the holder - you might produce a short circuit due to design of some battery holders. If that happens, your battery will heat up and die. So try to be quick and precise when inserting.

Adding this to service thread.
Old 19th January 2010 | Show parent
  #5
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rids's Avatar
 
🎧 15 years
Quote:
Originally Posted by Don Solaris ➑️
Open the unit so that you can reach the bottom of the PCB. Unsolder the battery. Check the voltage and size (exact type is irrelevant) then go to store with it.

Buy the one with the same voltage and size. If they have machine there to add leads to the battery please tell them to do so. If not, then as Flat Earth suggested, buy a battery holder there that will fit the same battery. Battery holder is a better solution anyway. DON'T try to solder the battery itself (if you don't have a holder) to provide it with leads. It might explode! Rather go to other store until you find the matching holder.

Take care when inserting the battery into the holder - you might produce a short circuit due to design of some battery holders. If that happens, your battery will heat up and die. So try to be quick and precise when inserting.

Adding this to service thread.
So I took some pics and want to make sure I do this right, since the closest thing I've done to tech work is use deoxit on my PEK.

So basically you're saying to unplug all the connections on the main board and lift it out of the case so I can look underneath the main board and desolder? When I desolder, am I desoldering the metal holder that's holding it, or under the board is it obvious how to desolder just the battery? It almost looks like the battery could slide out, but it feels snug in it's slot (and not that I doubt it's soldered in).

Here's my pics:





The battery seems to have some white dust (acid?) too under it on one side.

Old 19th January 2010 | Show parent
  #6
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flat's Avatar
 
🎧 10 years
Rids, that battery in the pic has the 'holder' soldered onto the battery itself. You need to remove the board to get access underneath to de-solder the 2 holder legs. Either replace it with an identical battery with legs attached, or put in a holder (see below, same as bios battery holder on most pc motherboards) then just slip in a new CR 2032 battery.

As Don points out, be very careful when performing this job, these 20+ year old instruments are quite fragile inside. Make sure you have the 2 legs inserted the right way round when re-soldering in.

Old 19th January 2010 | Show parent
  #7
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🎧 15 years
The only thing is the wires that are connected to the main board aren't coming out. I got two big connector/wires out, but the rest seem like the wires are connected/soldered straight to the board. Especially those little ones you see in the first picture by the battery. Those don't seem to have any release switch on that white plastic. I have pulled on them pretty hard and think either I can pull on them harder and they maybe will come loose or I'll just break the wires by trying to pull them out.

Not sure what to do at this point as there is no way to remove the main board without removing those wires from the board.
Old 19th January 2010 | Show parent
  #8
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flat's Avatar
 
🎧 10 years
Quote:
Originally Posted by rids ➑️
The only thing is the wires that are connected to the main board aren't coming out. I got two big connector/wires out, but the rest seem like the wires are connected/soldered straight to the board. Especially those little ones you see in the first picture by the battery. Those don't seem to have any release switch on that white plastic. I have pulled on them pretty hard and think either I can pull on them harder and they maybe will come loose or I'll just break the wires by trying to pull them out.

Not sure what to do at this point as there is no way to remove the main board without removing those wires from the board.
Its hard to see the connectors in detail. Sometimes they have an edge that can be prised gently with a screwdriver from the top, which allows the connection to come apart. Maybe a close up of one of the connectors would be a good idea. Certainly never force anything!
Old 20th January 2010 | Show parent
  #9
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flat's Avatar
 
🎧 10 years
hmm, the orange ones should definatley come loose. a little side to side motion should pull them free. But dont force anything. Remember these connections are decades old and may well have become tight over time.

The white connections, im not so sure about. They look very similar to ones found on older pc motherboards. These come directly off, leaving just the pins (prongs) sticking up. ie, if theres 3 wires, then three pins should be left after pulling off. As before don't force it. A gentle but firm side to side motion should be enough to work them loose.

If in any doubt, i'd consider taking it to a tech.
Old 20th January 2010 | Show parent
  #10
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Don Solaris's Avatar
 
4 Reviews written
🎧 10 years
I use pliers for every connector that is made of two parts. If it is one part, then obviously you don't want to pull that. Leave them and try to lift / lean the board just enough to reach with soldering iron.
Old 1st July 2014
  #11
Deleted 2ecf148
Guest
my battery seems to be glued in..
Old 22nd April 2016
  #12
Here for the gear
 
🎧 5 years
Sorry to dig up an old thread ( rather than starting a new one).

I've recently replaced my mks-50's old soldered on battery with a new battery holder and inserted a new cr2032 battery.

However it keeps prompting me on the battery low error on every startup. If I switch it off for more than a min, the battery low msg will appear and any edits or sysex data saved will be gone.

I've checked the service manual and it mentioned in one part about battery checking: To test between pin 24(vdd) and pin 12(ground) on ic8 (ram chip), and I shld have a voltage reading of around 2.8-3v. As I have no real knowledge on electical circuits, I used a multimeter and measure between pin 24 and pin 12. No voltage... am I measuring it wrongly? Or is the ram chip dead?

Also for the ram chip which is supposed to be a toshiba tc5564pl-20, mine was fitted with tc5564pl-15 instead. Any issues if fitted with a faster ram chip?

I have read up on the datasheet on tc5564pl layout and it seems that ground pin on the chip is on pin 14, and not wat the service manual mentioned in pin 12...

Sorry for the questions as I am trying desperately to get it fixed up and working...

Please help..
Old 19th July 2016
  #13
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🎧 5 years
radiolite22, did you solve this problem now? I have the same problem as yours. Even I changed the battery and do all the initialize procedures I still get the "check battery" message and the memory is still screwed up. I can only restore to the factory preset by pressing the 4,8 button on power on.

Should I change the RAM too? what parts should I get and where?
Old 31st July 2016
  #14
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interruptor's Avatar
 
🎧 5 years
Hi! My mks-50 has the same problem: After replacing the battery the memory content is lost as soon as the power switch is off for more than a few seconds.
This seems to be a common problem.
I checked with an oscilloscope and found some ugly voltage spikes on the RAM power supply during the power-up of the device. I therefore replaced all the capacitors in the corresponding section of the power supply. The idea being that these capacitors should even out the supply voltage. However this did not solve the problem; The memory problem prevails and the spikes also. In fact I currently doubt whether these spikes are actually a real problem, they could also have been picked up directly by the oscilloscope probes "wirelessly".
I was already thinking about replacing the RAM. This component could be bought via mouser.com. I am somewhat hesitant of going that route though since unsoldering a RAM is more challenging, and I am not experienced with this type of repairs at all.
If you want to have a look at the mentioned spikes check this thread here:
Forum β€’ MKS-50 vergisst seine Presets, kopfkratz
(in german.. you might need Google translate to understand.)
Old 10th September 2016
  #15
Here for the gear
 
🎧 5 years
Well, I did replace the RAM too. I ordered the same RAM TC5564PL-15 TOSHIBA from ebay and have high hope to fix this problem. I did so because the RAM's pins are rusted and one is even broken (pin 1 is broken). Desoldering the RAM isn't that a big problem.

I purchased the same battery as the original one from ebay (the one with three legs mount soldered to the battery). Desolder the old one, clean all the solder that was left behind. And solder back the new battery. Then I check the RAM (IC8) pin 28(Vdd) and pin 14(GND), it has a reading of 2.79V. (well this part is different from the service manual which is using TC5564PL-20 RAM as reference, this may cause confusion)

So, I init the RAM according to the manual, and restore all the factory presets via MIDI sysex files.

My best guess of why I did not succeed at the first attempt is as follows:
1) I used a 'holder' for the battery instead of original one, which has only two legs. Although it can fit in the board, I am not sure the electricity can go through the circuit. Since I do not get readings from the RAM. (maybe the RAM is not function too)

2) My old RAM is not working, since one pin did fall off. So I suppose it is not functioning properly anyways.

Good luck to you all.
Old 13th December 2016 | Show parent
  #16
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🎧 5 years
Quote:
Originally Posted by truman.kong ➑️
Well, I did replace the RAM too. I ordered the same RAM TC5564PL-15 TOSHIBA from ebay and have high hope to fix this problem. I did so because the RAM's pins are rusted and one is even broken (pin 1 is broken). Desoldering the RAM isn't that a big problem.

I purchased the same battery as the original one from ebay (the one with three legs mount soldered to the battery). Desolder the old one, clean all the solder that was left behind. And solder back the new battery. Then I check the RAM (IC8) pin 28(Vdd) and pin 14(GND), it has a reading of 2.79V. (well this part is different from the service manual which is using TC5564PL-20 RAM as reference, this may cause confusion)

So, I init the RAM according to the manual, and restore all the factory presets via MIDI sysex files.

My best guess of why I did not succeed at the first attempt is as follows:
1) I used a 'holder' for the battery instead of original one, which has only two legs. Although it can fit in the board, I am not sure the electricity can go through the circuit. Since I do not get readings from the RAM. (maybe the RAM is not function too)

2) My old RAM is not working, since one pin did fall off. So I suppose it is not functioning properly anyways.

Good luck to you all.
Hi, so did you managed to fix the unit?

Has changing the ram chip and 3 leg battery solved your problem? If so I may give it a shot as well.
Old 14th December 2016 | Show parent
  #17
Here for the gear
 
🎧 5 years
Quote:
Originally Posted by radiolite22 ➑️
Hi, so did you managed to fix the unit?

Has changing the ram chip and 3 leg battery solved your problem? If so I may give it a shot as well.
All fixed and work perfectly. Make sure you clean up the solder properly
Old 14th December 2016 | Show parent
  #18
Gear Head
 
interruptor's Avatar
 
🎧 5 years
Quote:
Originally Posted by truman.kong ➑️
All fixed and work perfectly. Make sure you clean up the solder properly
Congratulations! That's great news. I am temped to also give it a try.
In my case the RAM works fine while the unit is ON (Even storing patches to the RAM and reloading them). However it looses the memory content once the power is switched off for more than a few seconds. As I understand from your post your RAM did not work at all, right?
Old 3rd September 2020 | Show parent
  #19
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interruptor's Avatar
 
🎧 5 years
I have also exchanged the RAM-chip in the meantime. It now works fine!
Since the original RAM is hard to get these days I used the slightly newer and faster version "TC5564APL-15".


Quote:
Originally Posted by interruptor ➑️
Congratulations! That's great news. I am temped to also give it a try.
In my case the RAM works fine while the unit is ON (Even storing patches to the RAM and reloading them). However it looses the memory content once the power is switched off for more than a few seconds. As I understand from your post your RAM did not work at all, right?
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