Extron Crosspoint Issues? / Questions (75 Ohm Sync)

[letsgome]

I was able to get an extron crosspoint 16x16 that does audio and video for $20.
I absolutely love it!!!! but I need some help to be honest. I have 2 questions that I hope the experts here can answer.

For context: I have recapped the power supply and cleaned all the connectors. I also put 470hm 0.6W Resistors on 3 of the output lines since I saw online that it should bring the TTL sync down to 75 ohm. The reason for this is because I wanted to output to my PVM and to my retrotink 4k simultaneously. I already had a bnc to scart converter on hand, so I figured it would be better for me to just put the resistor in the Extron rather buy a bnc to VGA cable.

1. Regarding the 470ohm resistor mod are the readings I am getting actually 75 ohm sync? I am using an RCA Y adapter to send it to both the PVM and the scope at the same time, so it get terminated. I don't know exactly what it is supposed to be, but I can't help but feel like something is off here:

Picture of the Resistor Mod:

Spoiler

Scope readings I get from the csync lines that have been modded:

Spoiler

2. The Extron makes this awful hissing noise for the first 30 minutes after powering on the system and whenever I send a signal through it. Is this normal? If not any ideas as to what it may be? The Extron also takes about 15 minutes to warm up to actually start working.

Video of sound: (for some reason I feel like youtube lowers the volume on shorts automatically this is actually very loud)

Spoiler

https://www.youtube.com/shorts/KiWprqIeBS4

edit on this issue:
I have done a little bit of testing. If I plug just the Red, Green, Blue, and H sync board in I get no hissing at all and it boots up instantly.

If I plug in any other boards or only plug in only one of each of those boards I get the hiss, but for some reason those 4 boards together work fine.

Thank you in advance to anyone who takes their time to reply.