ok I will look into another adapter. this is the adapter I bought so people know to stay away. https://www.amazon.com/dp/B0819X8V28
I also tried the adapter in my N64 without the hdmi adapters usb power cable connected and it worked anyway. so for the time being I will just use it without the power source to prevent any harm.
I recommend an HDMI adapter for N64. They work like a charm.
This is the one I got. Works for N64, GameCube and Wii https://www.amazon.com/N64-HDMI-Converter-Support-16-Nintendo/dp/B0819X8V28?pd_rd_w=AcUGV&content-id=amzn1.sym.1db61dc1-18bd-4e84-ade3-9872a4852ad6&pf_rd_p=1db61dc1-18bd-4e84-ade3-9872a4852ad6&pf_rd_r=584WNBEJHXRMTYKXE995&pd_rd_wg=RgTrl&pd_rd_r=4306eb1c-6f35-4eb5-aeb8-52f2cfeee17e&pd_rd_i=B0819X8V28&psc=1&ref_=pd_bas_bia_rpt_ba_s_1_sc
If OP is using an HDTV, I recommend going a step further and buying either the Oneme N64 To HDMI converter, the Laboen N64 To HDMI converter, or the Hyperkin HDTV cable... All three are relatively cheap.
If you want even better quality, go for the EON Super 64 adapter, which is the one I have and works great. Or you can go all-out and mod your console with an UltraHDMI mod.
Do you have another TV you can test? Preferably one where you can plug the Composite cable in directly without the HDMI converter?
Best to confirm it's not the TV.
I had one of those garbage AV to HDMI converters and it would do the same thing.
This was what I was using: https://www.amazon.com/gp/aw/d/B0819X8V28?psc=1&ref=ppx_pop_mob_b_asin_title
It would only sometimes work, sometimes no audio, sometimes no video, sometimes both didn't work. Would need to keep flipping the 4:3 and 16:9 switch back and forth until it did.
If that wasn't enough the video output looked awful.
Do yourself a favor and look into a S-Cable + Retrotink 2x Mini / 2x Pro / 5x or an HDMI Mod or RGB Mod, admittedly they aren't cheap solutions but they work very well and are the only way you are going to get a decent display out of an N64 on an HDTV. There is no other way.
I got a Retrotink 2x Pro and with the Scanline Filter the picture is significantly improved over that AV HDMI converter and it works 100% of the time.
Otherwise get a CRT.
There is also the very pricey Eon Suoer 64 HDMI converter but it's very, expensive, isn't as good as a Retrotink and only works on N64 whereas Retrotink works with other retro consoles.
Here’s a link to it if that helps.
Y.D.F N64 to HDMI Converter... https://www.amazon.com/dp/B0819X8V28?ref=ppx_pop_mob_ap_share