Ressurecting a Powerfunctions v1 receiver from the dead

[XG BC]

So i have this dead lego powerfunctions receiver laying around that i have fried a couple of years ago. the receiver part still works but the motor driver is completely dead so the led blinks as if it received something but no motor spins. My plan is now as i have a couple of ln 293d h-bridge drivers and a soldering iron to cut out the old driver and solder in the new one into an external breadboard which i will connect to the og pads. it will be a bit frankensteined but who cares if it works and you can save ressources in the process. has anyone of you ever done this and what are your thoughts about it? I will update this thread with progress once i come around to doing it.

[Zerobricks]

I can send you a few of mines, since I don't use them anymore.

[TechnicRCRacer]

I need to fix a V2 receiver with a break in the wire. Has anybody found a clean way to strip the rubber coating from the end of a PF wire?

[Toastie]

  On 12/17/2021 at 9:51 PM, TechnicRCRacer said:

I need to fix a V2 receiver with a break in the wire. Has anybody found a clean way to strip the rubber coating from the end of a PF wire?

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It depends on where the wire is damaged. When close to the receiver, and you can live with a shortened wire, just cut it, open the receiver, remove the remaining piece of wire, and press fit the cut wire in place again.

Best
Thorsten

[XG BC]

  On 12/17/2021 at 9:30 PM, Zerobricks said:

I can send you a few of mines, since I don't use them anymore.

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thanks but this is more of a trying to fix something then a i need a pf receiver now. am a thinkerer

  On 12/17/2021 at 9:51 PM, TechnicRCRacer said:

I need to fix a V2 receiver with a break in the wire. Has anybody found a clean way to strip the rubber coating from the end of a PF wire?

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seperate the wires with sharp siccors but be careful not to slice one open. after that its just the normal wirestripping process

Edited December 17, 2021 by XG BC

[TechnicRCRacer]

  On 12/17/2021 at 10:29 PM, XG BC said:

seperate the wires with sharp siccors but be careful not to slice one open. after that its just the normal wirestripping process

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Thank you! It’s really close to the receiver end so it won’t shorten the wire my much. 

[XG BC]

  On 12/17/2021 at 11:20 PM, TechnicRCRacer said:

Thank you! It’s really close to the receiver end so it won’t shorten the wire my much. 

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no problem! had to deal with seperating pf wires often so i know how it is done now

[XG BC]

i have now reopened the receiver and removed the obviously defective motor driver.

here you can see how the driver is obviously broken just by looking at it.

and here it is gone now when powering it up the receiver part does not heat up anymore like it did when the broken ic was in place. the led still blinks but ofcourse no output. if anyone has the scematic for the driver ic please post it here.

this will be the chip thats going in. and no thats not a special trick or anything the ln293d really is that big compared to the chip it replaces. it will be mounted on a daughterboard in a socket

will post new progress soon!

Edited December 18, 2021 by XG BC

[2GodBDGlory]

Interesting! I don't know much about how circuit board components, so could you explain how you knew the driver was broken?

[Johnny1360]

It kind of looks like the chip has a hole burnt into it, lol. Other than obvious physical damage though, it would be just a matter of testing individual parts on the board, I would think.

[XG BC]

  On 12/19/2021 at 12:43 AM, 2GodBDGlory said:

Interesting! I don't know much about how circuit board components, so could you explain how you knew the driver was broken?

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it looks like the chip is broken because it a: visually looks broken, b: the receiver part still works just the output didnt and if you google the broken chip it says dual motor driver so some educated guessing helps and c: the chip still smelled burnt but no other component did.

[Johnny1360]

All the magic smoke escaped, lol.

[XG BC]

  On 12/19/2021 at 4:33 PM, Johnny1360 said:

All the magic smoke escaped, lol.

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only the one from the driver chip luckily. the receiver one is under an epoxy blob. good luck fixing that!

[Toastie]

  On 12/18/2021 at 2:28 PM, XG BC said:

if anyone has the scematic for the driver ic please post it here.

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This is not from me but from @Mortymore. There is a thread here on EB - here is the link to the many interesting things he started/did:

https://www.eurobricks.com/forum/index.php?/profile/4317-mortymore/content/&type=forums_topic_post&page=2

Here is @Mortymore's Brickshelf gallery regarding the PF receiver:

https://brickshelf.com/cgi-bin/gallery.cgi?f=442112

There is his hand drawn schematic - I have searched a lot, before I equipped my PF receivers with an RF receiver; did not find anything better. Maybe it helps (it helped me a lot!!!

I hope it is OK to post your image here @Mortymore, if not, please let me know!

All the best and good luck with your project @XG BC, looks like much fun!!!

Thorsten

[XG BC]

  On 12/19/2021 at 8:10 PM, Toastie said:

This is not from me but from @Mortymore. There is a thread here on EB - here is the link to the many interesting things he started/did:

https://www.eurobricks.com/forum/index.php?/profile/4317-mortymore/content/&type=forums_topic_post&page=2

Here is @Mortymore's Brickshelf gallery regarding the PF receiver:

https://brickshelf.com/cgi-bin/gallery.cgi?f=442112

There is his hand drawn schematic - I have searched a lot, before I equipped my PF receivers with an RF receiver; did not find anything better. Maybe it helps (it helped me a lot!!!

I hope it is OK to post your image here @Mortymore, if not, please let me know!

All the best and good luck with your project @XG BC, looks like much fun!!!

Thorsten

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that is perfect! thank you! maybe ill make a prettier one using kiCad and post it here