Singer Sewing Machine motor driver chips - cannot identify - Page 1
Forum section: electronics / repair

author: flyflytn
author_rank: Newbie
timestamp: July 01, 2023, 12:50:07 am
content: Hi all,my wifes Singer 9985 sewing machine blew a (stepper?) motor driver chip, and I cannot identify it, or even the other 3 similar ones on the board. They are all 16 pin chips, with a metallic top - see pic, the one on the right has popped its rivets.The numbers on the blown one is:402K1F - which I cannot find any datasheets on, an alternative number printed on it is "10 323" which doesn't help it seemsThe other chips are "629K1F" with "15 313" printed on them as well.Does anyone know what these are ?cheers folks

author: PwrElectronics
author_rank: Regular Contributor
timestamp: July 01, 2023, 03:23:12 pm
content: Its possible there are more markings on the other side of these upside down mounted parts.Since you have nothing to loose with the fried one, take it off and look. Its already fried, so the safe approach to not damage the board is cut all the pins next to the body rather than try unsolder the whole thing. Use a cut off disk or very sharp knife. It will be a lot easier to remove each of the cut legs from the PCB separately later with solder wick.

author: fzabkar
author_rank: Super Contributor
timestamp: July 01, 2023, 08:26:27 pm
content: Here are two Singer PCBs:https://f01.justanswer.com/uxRVYLvr/20210216_190702.jpghttps://d3at71ghfqf560.cloudfront.net/php/image.php/graphics/00000001/25/416398301.jpgBoth appear to have been made/designed by "Happy". Happy Japan make their own sewing machines:https://www.happyjpn.com/en/product/sewing/Therefore, the components were most likely sourced from Japanese manufacturers.Here are some parts for the 9985:https://www.sewingpartsonline.com/singer-9985-quantum-stylist-touch-parts.aspx?filter.ptype_gmcfeed_1=+Electrical&index=1The motors appear to have been manufactured by Nippon Miniature Bearing Co., Ltd.https://nmbtc.com/resources/stepping-motor-engineering/The logic gate (TC74HC00AF) is a Toshiba part.My guess is that the motor driver ICs were made by Rohm or Toshiba. I would consult the catalogues and databooks of that era.https://web.archive.org/web/20230000000000*/rohm.comThe IC part numbers would suggest date codes of 323 and 313, so weeks 13 and 23 of 2003 or 2013. You could compare these YWW (Year/Week) codes against the code on the TC74HC00AF.That said, the other PCB has a marking code of 629K2F, so that's an anomaly (?) that bears consideration.

author: amyk
author_rank: Super Contributor
timestamp: July 02, 2023, 07:15:57 am
content: Who mounts motor drivers upside-down? That thermal pad is supposed to be used for heatsinking.... which may at least explain why one of these self-destructed. The markings on the bottom are package lot/date codes. The real marking will be on the top (now bottom) so remove the blown one and flip it over.

author: langwadt
author_rank: Super Contributor
timestamp: July 02, 2023, 11:55:29 am
content: Quote from: amyk on July 02, 2023, 07:15:57 amthermal pad on top so you can mount a heatsink, if needed

author: flyflytn
author_rank: Newbie
timestamp: September 12, 2023, 05:37:57 am
content: Hi Sorry, for the late thanks! I've been elsewhere....I had already taken the chip out, and there are no markings at all underneath...thanks for the tip though

author: flyflytn
author_rank: Newbie
timestamp: September 12, 2023, 05:42:01 am
content: Quote from: fzabkar on July 01, 2023, 08:26:27 pmOK thanks, good suggestions, I'll take a look and do some more hunting.In my initial searches, I found a complete replacement board for about US$280 but it seems such a waste just for a single blown IC. I may have to resort to that if I cannot ID these.cheers!

author: tooki
author_rank: Super Contributor
timestamp: September 12, 2023, 01:56:35 pm
content: Quote from: amyk on July 02, 2023, 07:15:57 amThere you go once again, authoritatively making totally false statements based on your lack of knowledge.They aren’t mounted upside down. An exposed thermal pad is, as langwadt said, for attachment to a heatsink. This package type is used when a solder-side thermal pad (soldered to the PCB) can’t provide enough cooling. (Of course, attaching no heatsinks at all isn’t going to provide adequate cooling, either, unless they’re basically wildly oversized for the loads in question.)For example, look at the TI TPA3128 and TPA3126 speaker amplifier ICs, which come in pin-compatible TSSOP packages: the ’28 has a solder-side thermal pad, while the higher-power ’26 has a top-side thermal pad for the express use with a heatsink.Bottom-side PowerPAD:https://www.ti.com/lit/ml/mpds380a/mpds380a.pdfTop-side PowerPAD:https://www.ti.com/lit/ml/mpds503a/mpds503a.pdf