John wrote:
AJ wrote:
ESR the caps in the vertical deflection circuit, may find numerous
ones due to age of the monitor. Change any that check out of tolerance
and change the vertical output device.

Thanks for your feedback guys. However it's been so long since I've
poked around inside a monitor / TV that I am uncertain where to look.

Is the vertical section you refer to, the LOPT etc ?

I was considering looking on ebay for another one of these but if I
could resurrect this one, I would save a few pennies. However it is
possible, this unit may be on its way out. The brightness is up full, to
get a normal picture. When using separate chroma and luma inputs from
the C64 computer, colours still "interfere" with each other eg brown
text on a blue background is almost unreadable.

Anyhow, the immediate problem is these lines on the top third of the
screen.

I appreciate your help.

The 1084 was a good CGA monitor for the C=128, but for the C=64 any NTSC
analog video monitor will do (using composite video combining luminance
and chrominance information). Also, turning up the brightness / contrast
of your monitor may increase the visibility of retrace lines near the
top of the screen.
Do the lines disappear when you turn the brightness down?
If you have to turn it up to max brightness to view the monitor, your
CRT could be failing. The cost of replacing the CRT could be more than
that of a used PC.
On the other hand, most cheap analog color TV's will have RCA-type
sockets that will fit the composite video / audio cable provided with
the C=64. The yellow connector is the composite output of your Commodore
computer.