Pvm 20n5u HDMI to composite adapter, black and white image

So I have a sony 20n5u that I picked up. It only has composite and s video at the moment. I plan to add an RGB input in the future but don't have the materials to do it yet. My question is about an HDMI to composite adapter. I was going to use it for streaming video through a Chromecast, but the image is only in black and white. I've tested the adapter on 2 other consumer TVs and it displays in color. I've also tested a gamecube over composite on the pvm and it displayed in color. It's only the Chromecast that's displaying in black and white and only when connected to the pvm. I swapped using 2 different sets of composite cables and the results were the same. I get color on the consumer set but black and white on the pvm. It's a cheap, ONN brand, HDMI to composite adapter I got from Walmart, so not exactly professional grade but it's worked fine up until this point. Are there any cheap HDMI to composite adapters that are known to work better with pvms?