Schematic for Air Fryer Power Board - Page 1
Forum section: electronics / projects

author: larrybud
author_rank: Contributor
timestamp: January 23, 2024, 03:39:15 pm
content: I have an "Innsky" air fryer, and one of the annoying things with it is that when you press the "light" button on the front panel, the light only stays on for just 120 seconds. I opened the machine up, and it has this power board (see attachments)RY2 is the relay which switches the lamp on, the LAP is the connector for the lamp.Underneath the board is IC2 (looks like a ULN2008, terribly difficult to read the number!)https://datasheetspdf.com/pdf/1429160/UTC/ULN2008/1The light signal comes in on pin 4 of this chip which outputs to pin 14 that drives the relay, so I think I have the correct chip.So the goal is to increase the timeout on the light. Worse case I just permanently short the relay so the light is on when the unit is on. It's not used so much that it would matter a whole lot, but I'd like to dig a little deeper.I'm guessing I need to open up the panel, as I don't see any processors on this board which would control the timing. Think I'm on the right track?

author: bostonman
author_rank: Super Contributor
timestamp: January 23, 2024, 04:50:13 pm
content: QuoteIt does appear that board is mainly for controlling power stuff since it has relays. Is it easy enough to put a fly lead on pin 4 and pin 14 and see if both pulses turn on/off at the same time?This would tell you if the chip is doing any timing.

author: larrybud
author_rank: Contributor
timestamp: January 23, 2024, 06:11:54 pm
content: I will definitely try that and report back.

author: larrybud
author_rank: Contributor
timestamp: January 23, 2024, 11:54:08 pm
content: Ok, so the IC is actually aULN2003darlington pair array. I was able to track 3 of the inputs into this and their corresponding output:Pin 2 -> 15 is for the heaterPin 3 -> 14 is for the fanPin 4 -> 13 is for the light.The header and light drive separate relays, while the fan operates a triac. The fan is on once the cooking process starts, until the unit is turned off (and about 10 seconds after that for a cool down period).Without a schematic, I couldn't find a way to turn the relay on for the light when the fan is running, which would be the optimal solution.Oh well, if anybody has a schematic for this board I'd be very interested. Thanks!

author: bostonman
author_rank: Super Contributor
timestamp: January 24, 2024, 12:02:56 am
content: Seems like you need to track the source to that board. It's probably controlled by a micro, but who knows, maybe you'll luck out and find a circuit such as a 555.

author: themadhippy
author_rank: Super Contributor
timestamp: January 24, 2024, 12:05:03 am
content: Quotedisconnect the input to pin 4 ,connect pin 4 to pin 3.Downside is the light will only come on if the fan is on

author: amyk
author_rank: Super Contributor
timestamp: January 24, 2024, 12:59:51 am
content: I'd just wire in a toggle switch, like the good old ovens used to have for their lights.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 24, 2024, 04:01:48 am
content: Just wire the light in parallel with the fan? The triac should be rated for enough current, but you can always check the datasheet first.

author: larrybud
author_rank: Contributor
timestamp: January 29, 2024, 04:42:33 am
content: Yep, tried that and it acted exactly as predicted.

author: larrybud
author_rank: Contributor
timestamp: January 29, 2024, 04:43:08 am
content: That's just crazy talk lol.