Power board for Frigidaire stovetop - Page 1
Forum section: electronics / beginners

author: k.delaney1995
author_rank: Newbie
timestamp: June 24, 2023, 05:07:28 am
content: Hey all! This is my first repair and I'm excited to dive in, i have in my possession a $2,000 range that I bought for $20! I'm trying to fix it because my range is broken as well. The problem with this range is that the stove top won't power on, after check all connections and giving it the once over for any signs of scorch marks ( the last owner stated that there was an electrical storm once and he believes that a surge of some sort could've fried his control board) i didn't know if i thought that to be the case especially after finding no crispy bits on the board. I did however locate a spot that looks like there was something corrosive that trashed the chip resistors, they won't read continuity (i have my meter from when i didn't electrical work, the probes are kinda big) and they look trashed to me, I'm hear to see what y'all think. Also i know if a capacitor blows it can leak corrosive electrolyte, the prongs seem to have some sort of orange fluid but it doesn't look that bad, i was always told you look for bulging capacitors. I appreciate any help and wisdom y'all could share with me 🫡. Go easy on me I'm just a washed up electrician who's now a maintenance guy trying to get a good oven for the family 😂

author: k.delaney1995
author_rank: Newbie
timestamp: June 24, 2023, 05:08:43 am
content: Adding some pictures because of post limit

author: k.delaney1995
author_rank: Newbie
timestamp: June 24, 2023, 05:10:05 am
content: More pics, directly flipped for reference

author: Gyro
author_rank: Super Contributor
timestamp: June 24, 2023, 10:04:47 am
content: Hi, welcome to the forum.You are a newbie so I will try to go easy. The photos are really bad though, unsteady, partly blurred and lots of shadows. You really need to take the photos in good light light (not the phone flash) and then resize them down to a sensible size. It's impossible to read any of the IC markings. In this case it probably wouldn't help though.What I can say is that it isn't a power board, it is a microcontroller board, controlling whatever inteligent functions the hob has. Just a microcontroller in the middle (the one with all the pins), with a bunch of unidentified input and output connectors (with what look like output buffers), oh and a bleeper. The only thing that may be power related is what looks like it might be a 3 terminal regulator (the upright component), but no markings visible from above of course, with an electrolytic capacitor (not bulging) next to it. This is probably just to supply the microcontroller and its buffers.I don't see any signs of corrosion, just some flux residue, either from rework or hand soldering through-hole parts. The orange blobs are adhesive, used for holding down the surface mount parts during machine soldering. I don't know what sort of electrician's meter you have but if it's an insulation and continuity tester, its continuity ranges are probably too low to register most of the resistors, and the voltage it puts out may well damage the microcontroller and other ICs.From all the connectors, there are a bunch of other boards in the stovetop, including a mains power supply board. I'm very sorry, but I don't see any way of diagnosing the problem with the tools that you have (in fact it would be difficult for anyone to diagnose that board in isolation).EDIT: I just spotted another couple of electrolytic capacitors but I don't see any signs of them bulging or leaking either.

author: k.delaney1995
author_rank: Newbie
timestamp: June 24, 2023, 03:57:20 pm
content: Thanks for the help, I'll just hook it all up and see if she cuts on. Of it doesn't work I'll just trace the power slowly back to the stove top. Sorry about the pictures, as you said i don't have the equipment nor the knowledge y'all do. If it helps any, here's another more clear picture of the chip resistors that i thought were the problem

author: Gyro
author_rank: Super Contributor
timestamp: June 24, 2023, 06:05:45 pm
content: Much betterThe two resistors I think you are meaning (marking 472) are 4.7k ohms - the marking is value (47) followed by number of zeros (2) ohms, so 4700. I don't know what your meter is capable of, but remember that they are probably connected in some way to the microcontroller. There is some flux residue (which tends to get kicked up as soon as you start prodding them with probes). The board may well have been soldered with so called 'no clean' flux that doesn't need to be washed off during manufacture.Putting it back together and trying to check the supplies is probably a good strategy. I would suspect the mains power supply board first, especially if there has been some sort of surge. Do be aware that something like a stovetop, the mains power supply may be a non-isolated type. As an electrician, this shouldn't be a problem for you as long as you are aware of a possible electric shock risk (relative to ground). Any big capacitors on the power supply board might retain high voltage after the mains has been disconnected too.