HC0303-1B

[martonmiklos]

Hi folks!

I am trying to repair a Daikin air conditioning unit's filter board where I came across this ceramic coated IC:


It is likely an AC-DC power supply converter, however there is no output voltage on it and I do not know if there are any enable lines for that.
The primary side is clearly understandable: it has AC input and has a DC rail where a 100V 470 uF is present, however on the secondary side there are 4 pins and their function is unknown.

I have not found any datasheets or schematics containing it on the web, so any guidance would be deeply appericiated on the identification.

I came across this logo in Japanese gear, however I do not know which company's logo is it:


Maybe the identification of the manufacturer would help too (finding similar devices in the portfolio for e.g.).

[truclacicr]

The logo belongs to Matsushita (Panasonic).

[martonmiklos]

The logo belongs to Matsushita (Panasonic).

Thank you so much!
Unfortunately my google-fu failed again, because Matsishita/Panasonic + AC DC converter or hybrid IC does lead to any relevant results

[truclacicr]

Have you looked for a service manual?

https://elektrotanya.com/showresult?...a=All&kat2=All

[truclacicr]

https://pl.aliexpress.com/w/wholesal...525252d1B.html

[lotas]

Where did you get the idea that this power supply module is more of an optocoupler module for exchanging inter-unit data (external - internal).
Interblock data exchange occurs between N (neutral) and S (signal)
https://www.ebay.com.au/itm/223993382690

[martonmiklos]

Have you looked for a service manual?

https://elektrotanya.com/showresult?...a=All&kat2=All

Yeah mine is not present on the tanya, just on Issuu from where it is not possible to download just as an image...
https://issuu.com/paulomoreno_dtp/do...nual_esie14-01

However it does not have any details about the board level repair.

Sourcing is one thing from Aliexpress, I would like to understand how it should work.

If I apply the 5V to the 7805 output the board low voltage part starts living: heartbeat LED blinks, service LEDs reacts to buttons.

However I do not know if the power module should be powered up by default or is it looking for some external signal from the other components of the system (what I do not have at hand at the moment).

[truclacicr]

https://next-energies.fr/wp-content/...a-LT-CB_FR.pdf

[lotas]

PCB EC0663(A)

[martonmiklos]

Where did you get the idea that this power supply module is more of an optocoupler module for exchanging inter-unit data (external - internal).
Interblock data exchange occurs between N (neutral) and S (signal)
https://www.ebay.com.au/itm/223993382690

This is an EC10011(C) board:


As you can see there is no details of the MCU or power module or whatsoever on the block diagram, however other than the 3F filtering it hosts an MCU with communication interfaces and driving a bunch of relays.

If I power up through Phase 3 (via L3A & Neutral) it powers up the mentioned HC0303-1B.
On heat camera the corner of the module starts heating up a bit, ~60 V DC appears on the primary electrolytic cap, however on the secondary side no power appears.

I traced the (presumably) output line of the module and the 7805 input line and they meet in an optocouple network what I have not yet analyzed further as the board is conformal coated (maybe it is the time for taking an acetone bath )

[lotas]

This switching board does not have a power supply, it is powered from another one, where the pulse transformer is located.
And the HC0303-1B module for switching (interconnect communication data exchange), if you look closely at this module from the back, you will see two optocouplers filled with compound.
You can see from the board that these four pins go to the controller, these are Tx and Rx, that is, input and output, and through this module through optocouplers it is supplied to high voltage and along this line S and N control commands go to the internal unit, and there is also such a module (or can be assembled using discrete components).

[lotas]

Look at the 12v input supplied to this connector.

[lotas]

Here is a rough diagram of this module, which you consider to be a power supply converter.

[martonmiklos]

Here is a rough diagram of this module, which you consider to be a power supply converter.

Ah I see the point now, many thanks for the explanation!