# 1231c-8601 parts



## Kerensky (Jul 8, 2011)

Hi all.
I recently bought a used s10 conversion on eBay. Low and behold I have encountered the random problem every so often. U know nagging little things like the 15 year old mixed brand/voltage battery pack and the c minus welding on the battery boxes and frame. Stories I'm sure you have all heard before,and issues which have already been resolved with the help of my local welder buddy and $3000 worth of t105's from my friendly neighborhood golfcart guy.(best day of his life man!) 
My latest issue is that my controller made the popcorn sounds and the magic smoke. Wait for it .......... Wait for it......... I am trying to rebuild it myself with the help of a work buddy. We work on roller coasters for a living so series wound dc motors and controllers aren't too far removed from our experience. The control board and circuitry are completely intact. The power side, however, is another story entirely.
We intend to replace the somewhat crispy 50A MOSFETs with ixth96n20p which aren't too difficult to find. What I cannot seem to get ahold of are the 18 "power diodes" Dr4180. They don't exist according to the almighty GooglEbay gods. Can't even find a data sheet for 'em. 
Has anyone here successfully rebuilt/uprated a Curtis 1231c-8601 before ? Any one know where I can locate some diodes to replace the proprietary Curtis ones that the "primary recomended service provider" won't even talk to me about?
Any help would be appreciated as I'm at my wits end. Not to mention the bottom of my pockets after those tasty batteries/ truck purchase/ transporting it from the highschool in Jersey to central Florida.


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## DJBecker (Nov 3, 2010)

Are those tab-mounted button diodes, or are they in standard TO-220 packages with three terminals?

Search for Motorola SR4180R4

Curtis frequently used diodes in a "reverse" configuration, with a common anode instead of the standard common cathode on the mounting tab. This allowed mounting the diodes directly to the heatsink, without an isolating strip.

This is a much more convenient configuration if you are designing a motor controller, but not if you need to purchase the parts. There are few diodes to choose from, and they are more expensive for the same specs.


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## Weisheimer (May 11, 2009)

This is the only diode that I am aware of that can be used in place of the original.

http://www.mouser.com/ProductDetail...=sGAEpiMZZMtEwUVCuofpuJ8elz361Z6mbGXa912nyj0=http://www.mouser.com/ProductDetail...=sGAEpiMZZMtEwUVCuofpuPyL2BKs19O0Tn9MHDM2sbs=

It is a dual 10 amp rated diode in reverse configuration, the same as the original, but you should note that the total current rating will seem low.


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## Kerensky (Jul 8, 2011)

from what ive found the 6 button type diodes are only used in the plug braking circuit..... not necessary (or safe in my opinion) for onroad use. We only intend to replace the 18 TO-220 power diodes.


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## domosher (Jul 10, 2011)

I have rebuilt many 1231c control units and have seen very few diodes fail.
They are rated at 25 amps and 200 volts and are of the reverse polarity version which drives the heat to the non heatsink side of the diode they have a 500 amp peak current rating. Usually the damage to the diode is cosmetic and can be repaired only one of the two leads are used in the 1231c except for in one location and even there it only to sample the voltage on the heatsink.


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## domosher (Jul 10, 2011)

When I upgrade 1231C I use a IRFP4668PBF it has 1/3 the on resistance of the part you listed.


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## brainzel (Jun 15, 2009)

Interesting thread ... because there is just so much knowledge available, a question from me:
would it be possible for you to post an "upgrade tutorial" for the 1231C to handle more current or the same current at lower heat exhaust or for a longer period of time?


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## ElectriCar (Jun 15, 2008)

domosher said:


> When I upgrade 1231C I use a IRFP4668PBF it has 1/3 the on resistance of the part you listed.


Are you done with mine yet??? Nice to see you on here! 
TC.


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## Tesseract (Sep 27, 2008)

domosher said:


> When I upgrade 1231C I use a IRFP4668PBF it has 1/3 the on resistance of the part you listed.


I'm not sure how current is sensed in the 1231C, but I seem to recall that in the 1221 it's done by looking at the voltage drop across the MOSFETs and/or freewheeling diodes when forward biased. If it's the MOSFET Rds[on] that is sensed then you might be tripling the current limit set point inadvertently by using ones with 1/3rd the resistance. 

Another thing to double-check is the total gate charge - Qg - of the replacement MOSFETs. If Qg is significantly higher then the MOSFETs will switch more slowly, leading to higher switching losses, while if Qg is lower then they will switch more quickly, leading to more spikes and ringing.

I'm not trying to dissuade any tinkering here, just pointing out some things which if overlooked could result in the controller failing on, so worth pointing out.


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## Kerensky (Jul 8, 2011)

Domosher, nice mosfets, what "TO-220" diodes do you use ?
Weisheimer's MUR2020R diodes will fit but they will be a bit under rated if i swap out the stock 50A mosfets for 90A much less the 130A monsters your recomending.
The nice sales lady at Mouser tried her heart out to find replacements, alas, to no effect.
The old guy at the local electronics shop "_Pin 3 cathode ?.....I'm pretty sure they don't make em like that."......_sigh...... thank you..... have a nice day.


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## Kerensky (Jul 8, 2011)

ok party people what is the general concensus if i try IXTH50N20 mosfets, and MUR2020RG diodes will that balance out the controller and enable my bech tech friend to get on with this rebuild ? i really miss my quiet truck.


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## domosher (Jul 10, 2011)

I use 22 ohm resistor in the gate lead oh each of the mosfets instead of 47 ohms I use APT100S20BG diodes on insulating pads and wire extensions 15 of them instead of the original 18 diodes these are 200 volt 120 amp schotkey diodes in a to247 package


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## Kerensky (Jul 8, 2011)

ok ..... so ... udate time on the rebuild...... we replaced all the power mosfets and free wheel diodes with IXTH50N20 mosfets, and MUR2020RG diodes..... dropped back into the s10 and all i got was sw200 clicks, no motion.
2 weeks of meter tracing and oscilliscope readings led us to the dead logic board so we ordered this list.
TC1410epa order 2
MC34074pg order 2
LM358n order 2
LM393n order 4
LM339n order 5
LM324n order 2

dropped the rebuilt controller back in yesterday... same result..... my brain hurts and im running out of time to make obamas tax credit...... anyone have any ideas ??????? i will admit that using my s10 as our only test rig is far from ideal but i cant fathom what it would take to build a motor cotroller test bench.... 
anyone in fla with some skills and free time? i would be willing to murder all the firtborn sons of Egypt to gain a mentor/ check my work.

brainzel i havent forgotten about you... im keeping pics and notes so when im done i can start your rebuild thread.... just not gonna open the thread yill i have actually gained the prerequisite knowledge & experience.


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## brainzel (Jun 15, 2009)

Kerensky said:


> [...] brainzel i havent forgotten about you... im keeping pics and notes so when im done i can start your rebuild thread.... just not gonna open the thread yill i have actually gained the prerequisite knowledge & experience.


Thank you. I follow your rebuild attentively. I would like to help you, but unfortunately I have little knowledge about this. Hope you get it back to work soon. Good luck.


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## eejay001 (Oct 31, 2013)

can i use this one in replacement of the MUR2020RG? http://philippines.rs-online.com/we...573743D737474683230303264692677633D424F544826


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## domosher (Jul 10, 2011)

no that part will not work you need the reverse polarity diode Allied Electronics has 49 in stock 10/31/2013


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## domosher (Jul 10, 2011)

the two smaller fets quite often get fried when the outputs get blown Q4 FU9014 and Q5 FU024


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## eejay001 (Oct 31, 2013)

thanks man


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## eejay001 (Oct 31, 2013)

Are there any other replacement diodes? cant seem to find MUR2020r here in the philippines


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## Weisheimer (May 11, 2009)

If you can't get the MUR2020R, then try Dave's suggestion in post 12 of this same thread.

http://www.diyelectriccar.com/forums/showpost.php?p=251654&postcount=12

Dave has probably repaired more of these controller's than anyone else and his advice on components comes from hard won experience.


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## summetj (Mar 30, 2011)

I've got a 1231c that blew out (at least) two of the MOSFETS near the logic board.

Here is my question:

One MOSFET on the power board (Q13) is different from all the others. First, it has 3 pins connected to the PCB, while all of the others only have 2 pins, with the third middle pin soldered to a ring terminal and connected to the heatsink via the mounting screw. Second, it is a Vishay IRFP254 instead of an IXTH50N20.

Are there 18 power mosfets (there are 18 freewheeling diodes), and this one random one that is for something different? Or did somebody replace one original IXTH50N20 already? (The fact that the PCB for it has 3 holes while all the others have 2 make me think it came from the Curtis factory this way...)

Is this guy part of the current sense circuitry? If anybody has a schematic for power or logic board that would be appreciated.



Photos and lots of text here:
https://www.summet.com/blog/2017/01/08/curtis-1231c-8601-500a-pwm-dc-motor-controller-teardown/

Thanks,
Jay


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