I had similar issues, I replaced all the LM339's on my boards and they all worked again. Once second all reels worked, then they didn't. How and why all LM339's on all reels blew at the same time, I can't answer. Worked ever since then though.
I hardly ever suggest starting with replacing chips, but if you're good at soldering, it's so cheap and easy.
If not, honestly, there are probably better troubleshooting steps to follow first.
Always use sockets when replacing something like this.