My new CTC-15

[old_coot88]

Great find. As you're probably already aware, the two ground stakes on the far right end of the chroma board exist in two states: either cracked or gonna crack soon. They need to be re-flowed as a matter of course on every CTC-12, '15, '16, '17 and '25.

When they fail, the heaters on the 6GU7s go out, causing the plate voltage to rise. Since the plates are DC-coupled to the CRT grids, this makes the CRT beam current go nuts, lugging down the HV supply. Pic blooms, loses focus and fades out.