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DIY Pa3X li-cobalt 6800mAh direct replacement St-By circuit

 
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AntonySharmman
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PostPosted: Tue Dec 08, 2015 2:53 am    Post subject: DIY Pa3X li-cobalt 6800mAh direct replacement St-By circuit Reply with quote

I know that some forum members have a deeper knowledge in Electronics and for that reason I publish a recent
design development I've made for direct replacement of Pa3X Ni-MH St-By batteries with 4 powerful NCR Lithium-Cobalt
batteries since almost all Pa3X factory batteries have already expired their charge circles.

The main reason of designing such a device is primary to increase at least 400% the stand by time duration , adding
another 8-10 years of batteries life using those 3400mAh NCR 18650 elements.
You don't have to open Pa3X case , batteries & small circuit board can fit carefully in bottom box where Ni-NH batteries
were kept before.
The replacement is very simple , just disconnecting red(+) & Black(-) cables from 6XNi-MH batteries and connect
the new circuit with NCR batteries as shown in diagram (also place the existing thermal sensor between new batteries)



In fact this circuit is a switching lithium charger with feedback power supply (schottky diode) of 7-7.2 Volts when
main power is switched off or unplugged , feeding Ram and preserving PCM data for 16 or more days ...
Charging of NCR batteries is accomplished automatically regardless of any Global menu indication and takes
advantage of the primary current regulator that already exists in Pa3X Ni-MH charger module so no MosFet heat sink is required.

A brief circuit description
The heart of circuit is the shunt regulator TL431 that controls this secondary NCR charger at 8.4 volts and
inhibits power P-mosfet from contacting , regulating charging at max. 8.4 volts where charging is over.
When main power (PSU) is turned off , schottky diode feeds Pa3X Ram , emulating previous battery pack with
an average of 7.4V - Schottky diode forwards voltage = 7 volts power supply.
It would be wise to use THIS little strip board in each Li-Ion branch of 3,7V in order to keep always batteries in balanced charging state.
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Music Conductor - Sound Engineer & Developer - Automotive SMPS/RF R&D - Electronics Engineer
PaSeries Demos - Kronos EXs Libraries <> WavesArt.eu - KorgPa.gr <> Facebook

Keyboards : Steinway-D, Kronos X, Pa4X 76, Pa3X 76, Montage 7 , Roland-XV88, Emu3,Emax II,Synclavier II,Yamaha DX Series, ΟΒ-8V


Last edited by AntonySharmman on Sat May 18, 2019 2:37 am; edited 2 times in total
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AntonySharmman
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PostPosted: Sat Oct 06, 2018 12:23 am    Post subject: Reply with quote

I re-publish this old article after request , since image links had been expired.

This is a more advanced project of the same period with current sensor limiter of current overloading protection of Pa3X existing charger.


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Music Conductor - Sound Engineer & Developer - Automotive SMPS/RF R&D - Electronics Engineer
PaSeries Demos - Kronos EXs Libraries <> WavesArt.eu - KorgPa.gr <> Facebook

Keyboards : Steinway-D, Kronos X, Pa4X 76, Pa3X 76, Montage 7 , Roland-XV88, Emu3,Emax II,Synclavier II,Yamaha DX Series, ΟΒ-8V


Last edited by AntonySharmman on Fri Apr 05, 2019 9:08 pm; edited 1 time in total
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Reuben
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Location: Sydney, Australia

PostPosted: Sun Oct 07, 2018 2:35 am    Post subject: Reply with quote

Thanks Antony I am sure this information will be invaluable to all Pa3x owners as their batteries start to die. Mine is still OK at this stage.
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klitosp



Joined: 15 Mar 2019
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PostPosted: Fri Mar 15, 2019 5:40 pm    Post subject: Reply with quote

Please Antony, could you re-publish this circuit diagram because the link is already dead? It would be very useful. Thank you !!!
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AntonySharmman
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PostPosted: Fri Apr 05, 2019 9:09 pm    Post subject: Reply with quote

Re-published !
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Music Conductor - Sound Engineer & Developer - Automotive SMPS/RF R&D - Electronics Engineer
PaSeries Demos - Kronos EXs Libraries <> WavesArt.eu - KorgPa.gr <> Facebook

Keyboards : Steinway-D, Kronos X, Pa4X 76, Pa3X 76, Montage 7 , Roland-XV88, Emu3,Emax II,Synclavier II,Yamaha DX Series, ΟΒ-8V
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klitosp



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Posts: 2

PostPosted: Sat Apr 06, 2019 2:31 am    Post subject: Reply with quote

Thank you very much Antony ! Να σαι καλα φιλε!
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Sasha Ustenskii



Joined: 16 Jul 2018
Posts: 3

PostPosted: Wed May 15, 2019 2:54 pm    Post subject: thermal sensor Reply with quote

Ciao
Vorrei sapere il tipo di sensore termico per comprare uno novo. Grazie

Hello
I would like to know the type of thermal sensor to buy a new one. Thank you
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Sasha Ustenskii



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PostPosted: Thu May 16, 2019 10:32 am    Post subject: type of thermal sensor Reply with quote

Please Antony - I would like to know the type of thermal sensor to buy a new one. Thank you.
Grazie.
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AntonySharmman
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PostPosted: Sat May 18, 2019 2:13 am    Post subject: Reply with quote

I had used the existing one as biased in factory circuit , I hadn't measured it's variables but I guess it's a common NTC Thermistor 10k
For instance like THIS
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Music Conductor - Sound Engineer & Developer - Automotive SMPS/RF R&D - Electronics Engineer
PaSeries Demos - Kronos EXs Libraries <> WavesArt.eu - KorgPa.gr <> Facebook

Keyboards : Steinway-D, Kronos X, Pa4X 76, Pa3X 76, Montage 7 , Roland-XV88, Emu3,Emax II,Synclavier II,Yamaha DX Series, ΟΒ-8V
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Sasha Ustenskii



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PostPosted: Sun May 19, 2019 8:53 am    Post subject: thermal sensor battery Korg Pa3x Reply with quote

Thank you very much Antony.
Grazie.
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