Does the power supply go "tick-tick-tick" when connected to this board?
25R on 5V is only 1W - are you sure it is 25 ohms? Without the Video ULA, maybe the logic gate inputs to IC47 are lifting the bases of Q4, Q5 and Q6 that would be around 27R - I always noticed that area being quite hot.
Has the board had any rework? Check that the any areas are clean and there are no solder bridges.
The old technique I used before I got a thermal camera was to put my hand over an area, then switch on the power, wait a minute or so, remove and repeat for the whole board.
25R on 5V is only 1W - are you sure it is 25 ohms? Without the Video ULA, maybe the logic gate inputs to IC47 are lifting the bases of Q4, Q5 and Q6 that would be around 27R - I always noticed that area being quite hot.
Has the board had any rework? Check that the any areas are clean and there are no solder bridges.
The old technique I used before I got a thermal camera was to put my hand over an area, then switch on the power, wait a minute or so, remove and repeat for the whole board.
Statistics: Posted by maniacminer — Wed Jul 30, 2025 2:34 pm