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Possibly fake AD633 violently heating up when inputs are connected

Fluffyboii

Member
1662587566535.png

I am trying this setup with 10k and 1K resistor dividers to have around 1V at pins 1 and 3 but when I ground pin 2 and pin 4 it starts heating up rapidly to a point it is too hot to touch. Sine I am suspicious that this chip is fake and I got it for 3 usd when it is sold for around 20 locally I did not expect it to work from start but I wasn't expecting it to overheat like this. All other chips I got from same seller functioned to some degree.
 

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Fluffyboii

Member
RC4200 is hard to come by in local stores since it is an old design so I would have to get it from China again. It seems like there is MC1496 and RC4200 circuit designs here. If I can get some locally I would like to try them. There was an article showing the insides of an fake AD633 which revealed that it was actually a RC4200 inside :D I wonder if the chip I got is actually RC4200. Maybe I should connect it as one and waste some time on it.

I wonder how well this would work with tl074.
 

Fluffyboii

Member
I wonder if you have the "JR" or "AR" chip. The pinout is different in such a way that the -Vs goes right into the Output Op Amp.

Reference: (Page 5)
It is AD633JN which got same pinouts as AD633AR. I tried connecting it both ways from datasheet and both did not work.
Why not get some proper LT44 transformers, and try doing it that way - your wrongly made transformers probably don't work well enough, and LT44's are easily available for little cost.
If they sell those here I would not go and get custom ones wind up for no reason. I can't source them locally. Buying from Ebay would add at least 20USD shipping cost. Maybe I can ask the same shop to wind a 600 turn one with thicker wire if you think it would be better.
 
Last edited:

Beau Schwabe

Active Member
"It is AD633JN which got same pinouts as AD633AR" ... but they are different pinouts ....if you wired it wrong the first time then correcting the wiring may not solve the problem since now you may have a damaged component.
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