@Dallas797 Welcome to the Carver site!!
I am no expert on this amp nor any other for that matter.
In looking at the service manual that is available here on the Carver Site I can possibly see why that poster mentioned to replace all 20. The RCA410 comes before the C1000's, so it might have some control over the four, so replacement might be necessary. That one looks to be some sort of gate keeper or gate driver for the other four in the line. Please someone correct me if I'm wrong.
Here is a picture of the back of the C500 showing the items and hopefully what you have on yours,
I don't have any cross reference on what to replace those items with.
I would reach out to Greg here Carver Amplifiers - Services - Nelion Audio to see if he can restore this amp.
I hope someone comes along to better help in the repair of your unit and give you guidance.
Wish you well with the repair of your unit.
@Sk1Bum Love that video!! Funny you should load that video. I was just at Cabela's Hamburg PA store looking at Shotguns and hand guns for, lets say, "Home Vinyl Defense Weapon".
Had some beautiful stuff.
@Sk1Bum @Receiver2000 And I could not stop at TajMo, I added Sonny Rollins/ Way Out West, Dexter Gordon/ Daddy Plays The Horn 180g, and Wayne Shorter/ Adam's Apple 180g.
I did not want the album to travel alone. As they say, Safety in numbers!
@Franzk the TajMo album is available here and you also get a digital download code. I ordered this today so I'm hoping that they don't forget to send me the download code.
https://store.acousticsounds.com/d/123381/Taj_Mahal_and_Keb_Mo-Tajmo-Vinyl_Record
@Sk1Bum @Receiver2000 OK TajMo is on order! Somehow a few other things showed up in my cart ........Wayne Shorter/Adam's Apple, Dexter Gordon/Daddy Plays The Horn, and Sonny Rollins/Way Out West.
@Sk1Bum did you get the 7inch 180 gr record or the CD of this album?
I was able to find the tracks on my Amazon music and put them on my play list but want a physical media to play.
Son over today. Have the cassette deck playing some Henry St. Claire Fredericks Jr. (Taj Mahal) and he is playing along with his new Resonator Guitar!!
Just hanging out playing the Blues!!