[gunner45]

They did the wrong check, testing for power levels - which tells you nothing about whether the signal is usable if it is polluted by noise. Digital TV fails because of poor quality - low MER (Modulation Error Ratio) and and high post‑BER (Bit Error Rate) - not because of low power. You need a third tech to do a proper job, i.e. check MER/BER on the specific QAM carrier frequency for channel 113/144 while the breakup is occurring. Good luck.