Here's what you need on your iDevice:
If you haven't already, install OpenSSH in Cydia.
If you are using SBSettings SSH toggle, be sure you turn SSH on.
Here is what you need to install on your Windows PC:
Download PUTTY installer from this LINK
Optional, Download WinSCP from this LINK. [Read this entire post first]
Now open putty. input your iDevice's IP address in the host name.
Once in here, it will ask you to "login as", enter root as user.
If you have not changed your SSH password, enter default password alpine when prompted. If you have changed your SSH password, enter it now.
at the command prompt type: apt-get update
Putty will now process all of your Cydia repo sources. Review the output for errors. Make note of what repo sources have errors.
From here, you can go into Cydia, tap Manage, and tap Sources.
Select Edit and delete the repo source or sources that showed an error in PUTTY. Reload Cydia and your errors should be gone.
You can also follow these steps to accomplish the same ONLY IF YOU ARE COMFORTABLE USING WinSCP.
Launch WinSCP and enter the IP of your iDevice as host. The user is root, and your password is the same as what you used in PUTTY.
When connected to your iDevice in WinSCP, navigate to /private/etc/apt/sources.list.d
From here, you can delete the offending repo source by selecting it, then deleting. If you don't see a particular repo source in the list, chances are you will have to double click cydia.list and you may find it in there. If this is the case, you can simply delete the source using your Cydia app.
You will no longer have any repo errors in Cydia.
And that's how Bruce T fixed Cydia Repo Source errors.