POE pcb not standards compliant- how to fix?

[Purduephotog]

I've been assembling a POE camera and the typical POE pcb from aliexpress has worked fine- for everything except one switch. That switch puts out -53.6V, as opposed to the -48V on nearly all the others I own.

The cheap Ali board (of which I've only ever found this type) apparently can't handle it. I've just finished probing it and it produces 16.8 or 17.0V when powered at -54V. So my gear isn't working. Other equipment that is POE compliant works fine in that switch, so it's obviously a defect in the design that it isn't handling the regulation properly.

I've managed to track down the circuit from the manufacturer-

http://www.silan.com.cn/UploadPic/20190620161725883.png

The POE pcb-
https://www.aliexpress.com/item/32874259693.html

I can't read the language, however I see some places that might have an impact- there's a 3.0V listed (of which I haven't found yet by probing) and there are a pair of resistors to feed an op-amp.

Looking at the circuit (I'll try to put up photos), the pin 7 goes to ground via a capacitor, which matches the block diagram. However without the language I fear I'm not going to be able to decipher much.

Seeing FB as 'feedback', there is a resistor bank of approximately 7.9K connected to pin 3 (as well as a capacitor I can't measure in circuit).

Were I to hit this with a scope, what would be a good place to start? Am I understanding the diagram the right way?

Thank you

[amyk]

What's the actual part number of that IC?

[Purduephotog]

SD4932B - that's the sad part. That's the PN of the DC/DC transformer AND the IC chip. The only place I've found the documentation is that PNG, which was a surprising post on a forum on Bao.

[shuum]

I've managed to track down the circuit from the manufacturer-
http://www.silan.com.cn/UploadPic/20190620161725883.png

Please renew circuit picture link please 

[LateLesley]

Well I had a wee look for the SD4932B, and I did find a pic of the circuit for it.

So I dunno if that will be of help? Looks like it's meant to be good to 57V.

[shuum]

Great thnx!!!
Unfortunately, this is not a diagram from the module https://www.aliexpress.com/item/32874259693.html from the post above, I'm looking for it. 

[Purduephotog]

Great thnx!!!
Unfortunately, this is not a diagram from the module https://www.aliexpress.com/item/32874259693.html from the post above, I'm looking for it. 

Sadly I never had the circuit for the POE board; I was specifically referencing the chip on that board (if memory serves).

[cjheath]

I came across this thread while exploring other PoE splitters. I don't know if this info is too late to be helpful.

The SD4932 is made by Silan. The English webpage for it is here and by submitting your email you can get the datasheet: http://www.silan.com.cn/en/product/details/2893.html

The same part number is on the transformer, but that's clearly wrong. Typical transformers used with this chip are PM3812R, as seen here: https://www.aliexpress.com/item/1005002768318128.html