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Help to identify 8 pin IC

bpjobin

New Member
Hi,

I have a problem with my eBike. Its electrical system contains these parts:
  • 48V mid-drive motor
  • 48V battery
  • display connected to the motor
  • remote connected to the display
  • speed sensor connected to the motor
The system boots, the display reads and update the data from the speed sensor. While riding, everything works fine as long as I leave the speed set to 0, meaning the motor won't engage to assist me pedalling. If I set the speed at 1-2-3 or 4, the display will shut off instantly. I don't hear or feel the motor at all. This quick diagnostic led me to believe that the display was faulty. I noticed a component that seams burnt on its PCB, but I'm having trouble identifying what it is and what it does.

IMG_9654.JPG
IMG_9677.JPG

What I can read so far is:
08BJ
91424
(Motorola logo) M6P

Anyone can help me identify this IC?
Also looking for a replacement if possible.

Thank you!
 

gophert

Well-Known Member
Most Helpful Member
That does not look like a Motorola logo, more like a Microchip "M".
 

simonbramble

Active Member
Here is my logic. That definitely looks like the Microchip logo. There is also a large inductor next to the package, so I suspect it is a power supply part ( a step down or step up regulator to regulate the voltage). The part is in an 8 pin SO package.

Most of Microchip's parts are made by Micrel and Microchip bought Micrel back in 2015. I suspect your design is much older than this, so I suspect the part is one of the original Microchip power supply parts (as opposed to a Micrel power supply part). Also, once Microchip bought Micrel, they would have continued manufacturing Micrel parts with the Micrel logo on the top (in the Micrel fabs). I cannot imagine they would have changed the logo immediately. So it is probably one of the original Microchip power supply parts. This narrows it down considerably.

There is destruction around pin 8 of the device. When power supply parts blow up, it is normally the switch pin (SW) that blows up since this experiences the high voltage. So I imagine you are looking for a Microchip part (the part number looks like it has '162' in the part number, but I am not sure) in an 8 pin SO with the switch pin near to pin 8 (not sure about this either). In contrast to that, the inductor is placed alongside pins 1-4 of the part, so this indicates that the switch pin will be along pins 1-4, although the PCB designer could have routed the switch pin from pin 8 over to the left hand side of the device (pins 1-4). This is indicative of bad board layout if he has!

That should help.

Now, the Microchip website is very slow this morning, so I will leave it with you to look deeper...

Simon
 

gophert

Well-Known Member
Most Helpful Member
The board has a 2014.4.16 date on the silkscreen. The chip has a week 24/2014 date stamp (1424 in the middle line).
 

rjenkinsgb

Well-Known Member
Most Helpful Member
It's difficult to be sure from the photos, but is there actually any pitting or missing material from the body of that IC?

The whole PCB has obviously been lacquered or conformal coated after assembly to help with weatherproofing.
The corner of that IC looks rather like the lacquer may just have been flaked off, leaving the original body material exposed.

I'm not saying there is definitely not damage, but the photos do not appear to show the usual cratering or cracking type effects that leave visible evidence of a failure.

The original symptoms make the fault more likely to be in the power control unit rather than the display, to my interpretation?
 

wkrug

Active Member
I've found 2 Chips:
Microchip EMC1424 - But this has 10Pins?!
LT1424 but this Part is from Linear Technology.
08BJ doenst give any proper Results.
There is an AT24C08B Chip by Atmel, but 2014 ATMEL was'nt a Part of Microchip.
 

bpjobin

New Member
Wow! I didn't realize that forum was so active! Thank you so much for you answers.

That does not look like a Motorola logo, more like a Microchip "M".
Indeed that very much more look like a Microchip logo.

It's difficult to be sure from the photos, but is there actually any pitting or missing material from the body of that IC?
There is no hole on the chip nor any frying part that most chip failures usually show.

The original symptoms make the fault more likely to be in the power control unit rather than the display
That would be the motor then and in that case, it shall be torn down!
I'll see if it has any sign of damage inside and post an update here with a link towards a new thread in the Robotics & Mechatronics sub-forum.

Thank you all
 

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