DC 220V Electric Motor Controller Circuit Mysterious - Page 1
Forum section: electronics / repair

author: Adam0606
author_rank: Contributor
timestamp: September 11, 2022, 02:41:20 pm
content: DC 220V Electric Motor Controller Circuit Mysterious Chinese IC , ground off markings can anyone help , 14 pin IC , as it is a circuit , please help me a lot .

author: golden_labels
author_rank: Super Contributor
timestamp: September 11, 2022, 05:52:27 pm
content: Without having the schematics and with a lot of traces not visible (this is a 2-layer PCB, isn’t it?) it may be hard to guess.Does NE556 in a speed control circuit make sense?

author: james_s
author_rank: Super Contributor
timestamp: September 11, 2022, 06:18:38 pm
content: First step in identifying a sanded off IC is locating the power pins. Once you do that it may narrow things down considerably. My first guess is it's a quad comparator or op amp, something like the lm324. Next would be a PWM IC like the TL494.

author: Adam0606
author_rank: Contributor
timestamp: September 11, 2022, 07:46:25 pm
content: https://pl.aliexpress.com/item/1005003092557771.html?spm=a2g0o.order_list.0.0.26d31c24qbw32T&gatewayAdapt=glo2polHere I found this chip , tomorrow I will take more photos of the chip to get where it is powered , the chip is 14 pin , tl494 is 16 pin .

author: Adam0606
author_rank: Contributor
timestamp: September 11, 2022, 08:33:03 pm
content: More attachments I am sending, please help, advice and find out what is the chip ?The circuit works with two IRFP 460 transistors connected in parallel .

author: Adam0606
author_rank: Contributor
timestamp: September 11, 2022, 08:39:32 pm
content: Here is a similar layouthttps://www.eevblog.com/forum/repair/pwm-driver-misterious-chip-mcu-or-standard/

author: wraper
author_rank: Unknown
timestamp: September 11, 2022, 08:51:19 pm
content: Does not look like marking is ground of. Looks more like there was no marking to begin with. Also IC seems to be covered in flux, I would clean it with alcohol or acetone and see is something becomes visible. As of what it is, IMHO there is a good chance it's an IC specialized for particular purpose, and not a general use stuff that people suggest.

author: fzabkar
author_rank: Super Contributor
timestamp: September 11, 2022, 10:56:01 pm
content: U4 is an MC34151 dual MOSFET driver:https://sites.ecse.rpi.edu//courses/CStudio/data%20sheets/DL128-D.PDFPins 2 and 4 are CMOS/LSTTL Compatible Logic Inputs with Hysteresis. Therefore ISTM that these must be PWM signals. Both seem to originate at pin #6 of U1.

author: Adam0606
author_rank: Contributor
timestamp: September 12, 2022, 03:19:31 am
content: I mean U1

author: fzabkar
author_rank: Super Contributor
timestamp: September 12, 2022, 03:28:32 am
content: Quote from: Adam0606 on September 12, 2022, 03:19:31 amYes, I know. However, knowing the function of U4 tells us something about U1. I was thinking that U1 might be a PWM controller or a multivibrator.

author: Adam0606
author_rank: Contributor
timestamp: September 12, 2022, 02:54:57 pm
content: I cleaned but nothing worked it looks like the IC has a well-washed name (designation) I will attach some more pictures, maybe someone can help me in determining what is this IC 14 pin U1, please help me a lot .

author: james_s
author_rank: Super Contributor
timestamp: September 12, 2022, 04:49:34 pm
content: Locate the power pins, then draw a schematic of the circuitry immediately around the IC, post what you find and someone can try to help you.

author: Adam0606
author_rank: Contributor
timestamp: September 12, 2022, 08:15:33 pm
content: OK

author: Adam0606
author_rank: Contributor
timestamp: September 13, 2022, 06:24:13 pm
content: I am posting what was visible on top , once again I am very much asking for your help in determining what this U1 IC might be .

author: Adam0606
author_rank: Contributor
timestamp: September 13, 2022, 06:31:12 pm
content: Can you help I posted a photo of what I saw on the board around the U1 IC

author: james_s
author_rank: Super Contributor
timestamp: September 13, 2022, 07:38:32 pm
content: Well based on that it's probably NOT something like the LM324. Does pin 14 connect to +5V?

author: golden_labels
author_rank: Super Contributor
timestamp: September 14, 2022, 02:29:41 am
content: Unless my eyesight is very bad, pin 10 seems to be wrong in your schematic. The one leading to C9. It should be connected to the middle of C9-R11 divider, and R11 seems to be driven by LM358 output (pin 7).What are the nodes marked pink in my attachment connected to? Use multimeter’s continuity tester to determine this. Note that I marked area above U1. It’s because it actually goes under U1, so it seems it either connects to one of its pins or has a via to the other side. Use the same method to tell if pins connected to the capacitors are not having other connections. Some circuits may use capacitors connected between pins and power lines (for timing or charge pumps), but otherwise it’s not a common configuration. In particular those three potentiometers placed just by U1 just beg to be probed.

author: strawberry
author_rank: Super Contributor
timestamp: September 14, 2022, 09:22:19 am
content: MCU

author: wraper
author_rank: Unknown
timestamp: September 14, 2022, 12:14:04 pm
content: Quote from: strawberry on September 14, 2022, 09:22:19 amNearly zero chance. MCU would not have multiple capacitors connected between its pins and GND.

author: golden_labels
author_rank: Super Contributor
timestamp: September 14, 2022, 04:51:56 pm
content: strawberry: what’s the reasoning behind identifying it as an MCU? And what kind of a microcontroller, considering that this is a very large set?wraper: while I do not think it’s a µc, note that we do not see the entire picture yet. OP has already marked one low-pass RC filter as a capacitor-to-ground. And we do not know what’s under U1. There are three potentiometers in its close vicinity, which do not seem as if they could be connected to anything else: R2, R3 and 电位器.

author: Adam0606
author_rank: Contributor
timestamp: September 14, 2022, 07:00:39 pm
content: You're right I got confused with this C9-R11, and under the IC there are vias to the other side , on Saturday I'll have more time then I'll try to write more and draw out , I'll ask and what IC can it look like ?, can it be LM324 ? .

author: Adam0606
author_rank: Contributor
timestamp: September 14, 2022, 07:16:18 pm
content: I'll ask , if I solder out the U1 chip could someone help me figure out what it is ? From tarnistor IRFP460 g is connected to resistor R25 R8 the other transistor g connected to R15 and R26 , R26 and R 25 is connected to MC34151 chip to pin 7 .

author: fzabkar
author_rank: Super Contributor
timestamp: September 14, 2022, 07:46:49 pm
content: Quote from: strawberry on September 14, 2022, 09:22:19 amA 14-pin PIC (eg PIC16F676) has the correct power pinout ...http://ww1.microchip.com/downloads/en/devicedoc/40039e.pdfI agree that capacitors on the I/O pins are unusual, except for pin #12 which would be the Vref pin for the ADC.

author: james_s
author_rank: Super Contributor
timestamp: September 14, 2022, 07:57:30 pm
content: Something I should have asked in the beginning, are you trying to repair this thing? Or do you want to build your own? If the latter, it's probably easier to design your own solution than to reverse engineer what is there. It is very easy to make a PWM source, there are numerous ways of accomplishing that.

author: Adam0606
author_rank: Contributor
timestamp: September 15, 2022, 05:29:58 pm
content: Hello, can the PWM source be made with a tl494 IC?I purchased this chip with the idea of use , but also if this chip was damaged , I check the electronic parts on the board .

author: james_s
author_rank: Super Contributor
timestamp: September 15, 2022, 08:42:31 pm
content: Quote from: Adam0606 on September 15, 2022, 05:29:58 pmSure, that's precisely what that IC is designed to do. Normally it is used in SMPS circuits but it can do general purpose PWM too.Some time back I built a refined version of thishttp://uzzors2k.com/index.php?page=multiinverterIt's a good example of using the IC as a basic PWM source.

author: Adam0606
author_rank: Contributor
timestamp: September 16, 2022, 04:36:40 pm
content: I purchased this chip with the idea of use , but also if this chip was damaged , I check the electronic parts on the board .