I am building a homebrew 8-bit computer on breadoards and PCBs with TTL logic IC's (LS, HCT and ALS families).
I'm using an ordinary phone charger to supply the required 5V, but some IC's are getting only 4V or less, even though it's working OK that's not good at all.
The total current required is pretty low, around 200mA, very within the power supply range. I've tried with a few different power supplies with no success. I've done some research and found out that cell chargers are regulated, so it wouldn't be a problem.
The computer has 6 modules, the module closer to power supply reads 5V on its IC's, and the more it gets away from power, the voltage gets weaker.
I tried to make a power rail directly connected to each module, with same results.
I could put the modules schematics here but it would make the question very long, so I will provide the links to them:
Modules 1 and 3 are already in PCBs, the others still in breadboards.
Are there any obvious project mistake here? Any help would be appreciated.
Edit: Could it be poor quality ICs from China the cause?