What's under this black blob?

[ThomsCircuit]

Im getting ready to re-make this board as it is somewhat corroded. Ive already replaced all the battery terminals and switch.
It is an umbrella light. Driven by 6 AAA batteries wired in two sets of 4.5volts. It has 8 leds that each had 1.5 K resistors producing very dim lights. I was just going to replace the resistors and the LEDS with brighter ones but this board is falling apart.
I can see there is a smoothing cap between VDD and ground but what do you think is under this black blob?

My new plan is 8 RGB leds fading into each color driven by a 555 and a 4029 but ill bring that up in another thread.

 

[AnalogKid]

An integrated circuit.

That assembly technique is called COB: chip on board. The IC die is bonded directly to the pc board, and then everything is covered in epoxy for protection. Very low cost for very high volumes.

The only way to figure out what the chip is is by reverse-engineering the circuit functions, and then guessing.

 

[ThomsCircuit]

That assembly technique is called COB

OK. Understood. I dont think ill tear it apart because as it was when it was new it had no other function than turning the leds on or off. And that was controlled by a mechanical switch. Perhaps its purpose was for something not included in the model i received. The leds however were extremely dim. they just about illuminated themselves. Im going to make a new board with my own controller so Ill be posting this in another topic.
Thank you.

NOTE: I have been re-reading the content you posted for my benefit on understanding the ULN2003/2004 IC in "HELP DEBUG CIRCUIT".

 

[Nigel Goodwin]

OK. Understood. I dont think ill tear it apart because as it was when it was new it had no other function than turning the leds on or off. And that was controlled by a mechanical switch.

It's probably a microcontroller, and if the switch is a push button one (they usually are) then the micro is doing that, and usually provides toggling between full and half power, and often a flashing light as well.

 

[ThomsCircuit]

It's probably a microcontroller, and if the switch is a push button one (they usually are) then the micro is doing that, and usually provides toggling between full and half power, and often a flashing light as well.

So i took some of the leds that came with the original and breadboarded them with 5V. they have the same brightness. Whatever its purpose was it has no effect on the output of the leds brightness. But thank you for your insight.