Not off to a terribly good start, Junie. Without a model number it’s going to be guess work. I have had nearly 50 years in the tvvideo trade and it may be nothing more than a high ESR cap in the psu. Humax are not immune from this. I find it “odd” you don’t have a model number, unless it’s been de-badged. I don’t know what the rules on this forum, and whilst I have a fully equipped workshop I admit I am not a Humax appointed agent. But I am considered a whizz-kid with SMPS circuits, (where your fault probably is)
PM me if you want. Tony Walker