Help Identifying Parts for Simpsons Washing Machine Mainboard - FIXED!!!! - Page 1
Forum section: electronics / repair

author: phoenixdigital
author_rank: Contributor
timestamp: December 17, 2022, 11:34:07 pm
content: Hi All,I was hoping to get some assistance identifying some parts for replacement on a Simpsons SWF10761 washing machine. I've actually got two of these machines and over the years they both failed with what appears to be the same problem with the 47ohm resistor burning up (see attached pic).A 47 ohm resistor which appears to be part of the circuit to convert 240V to 5V for the logic board. I tried replacing the resistor and it instantly blew so the issue is deeper into the circuit. Can someone please direct me to the parts on mouser or equivalent please?The picture has close up photos of each component of interest.DiodesD4 - Markings P10Y 1022 -??D5 - Surface mount marking US1M is it this part -https://au.mouser.com/ProductDetail/Taiwan-Semiconductor/US1M?qs=tHU%2FlV7kTyQtvhnvJdnZJw%3D%3DD6 - D7 - Marking MUR 120 is it this part -https://au.mouser.com/ProductDetail/637-MUR120OtherLNK364 -https://au.mouser.com/ProductDetail/869-LNK364GN-TLTRSB1 PCB name - What is this??? With marking 200A 06AL2 PCB name - Inductor??? Can't work out how to read the markingsI want to order everything at once from Mouser so I'd like to identify everything that might need replacement.What I've Tested So FarI suspect it's the LNK364 as I've tested all the diodes with a multimeter and with a signal generator (25V) and oscilliscope and they seem to be doing their job. I've checked the transformer for open circuit with the multimeter but there seems to be connectivity for both sides. The L2 inductor isn't burn't out and has conductivity even though I can't work out what value it is. All caps have been taken out of circuit and tested OK however I'll replace anyway whne everything arrives.For some context of the rest of the circuit essentially 240V AC enters that bottom resistor and works it's way up past the diode (half rectifcation) and cap (for smoothing) then it hits the transformer and LNK364 which I think generates the 5V for the logic components. The top side (from pic) of the transformer appears to have a center tap so I think the circuit is generating a +ve and -ve voltage for the logic and rest of board.Example circuits (screenshot attached) for the LNK364 which this circuit seems to be "close" to -https://au.mouser.com/datasheet/2/328/lnk362-364-1511784.pdfI've got a whole replacement board on the way but considering I've now had two fail in the same manner I figured I'd try to fix these for next time.

author: fzabkar
author_rank: Super Contributor
timestamp: December 18, 2022, 12:17:36 am
content: "200A" appears to be a Transzorb.http://www.smdmark.com/en-US/search/code?id=200a

author: phoenixdigital
author_rank: Contributor
timestamp: January 05, 2023, 02:14:05 am
content: OK I fixed it. I'd ordered most of the parts but the culprit ended up being the LNK364GN.Some of the parts* D5 = US1M -https://au.mouser.com/ProductDetail/621-USM* TRSB1 = 200A 006A Transient Supressor -https://au.mouser.com/ProductDetail/576-P4SMA200A* D4 = P10Y 1022 -https://au.mouser.com/ProductDetail/625-GP10Y-E3* R57 = 47 ohm 5W -https://au.mouser.com/ProductDetail/652-WS5M47R0J* U3 = LNK364GN -https://au.mouser.com/ProductDetail/869-LNK364GN-TL* L2 = Inductor 10uH -https://www.aliexpress.com/item/33016670639.htmlWhen inspecting the LNK364GN with a microscope and I saw what looked to be a tiny tiny blowout. Since I also had a second failed board I checked that one too and it had a similar failure. (see attached pics)I replaced U3, D5, TRSB1 & R57 on the first one and it came back to life. WIN!!! For the second board I just replaced the U3 (LNK364GN) & R57 and it also came back to life!!!Pretty happy with that. I now have two spares for the next time it fails plus a few extra LNK364's as well. I measured the voltages just past the transformer connected to the LNK364 and it was 8V and -5V so I've got a reference for any troubleshooting in the future.