I have a 1977 Panasonic Quintrix II set my grandmother gave to me, and I adore it because when it's working right, the picture is gorgeous. Almost like Technicolor color.:music: It has a problem with the picture. After it runs for a time, the picture will, at random intervals, quickly become very dark. Usually changing channels fixes it, but it is stubborn and I occasionally have to just wait for it to "fix" itself.:D Anyone know what this could be? Not sure, but I think the problem could be triggered by onscreen brightness levels.:scratch2:

try jiggling the channel selector and see if that solves it.

If this uses a varactor (pushbutton tuning with presets) then the varactor presets may need a deoxit bath.


sounds as though its just falling out of tune, but.....

You should also check the brightness, picture/contrast, and panabrite/panacolor switches. If they are dirty the symptom can occur as well.

All the customer controls should be cleaned. There could also be a bad solder connection on the chassis.

Reminds me of a 1980 or so Quasar I had which would go blank randomly. Turned out to be a combination of weak soldering around the flyback and also very dirty controls. Set worked for about 10 more years then I tossed it when the CRT began bleeding the highlights. Might not have even been bad, but I remember I used to run that set with the color and brightness very high. Probably also had around 1Billion hours on it too.

Your set sounds very cool. Maybe you can post a pic?

try jiggling the channel selector and see if that solves it.

If this uses a varactor (pushbutton tuning with presets) then the varactor presets may need a deoxit bath.


sounds as though its just falling out of tune, but.....

You should also check the brightness, picture/contrast, and panabrite/panacolor switches. If they are dirty the symptom can occur as well.

No varactor tuner. Flipping channels on the VHF knob seems to make it go away about 50% of the time. No bad reactions from the Quintrix or AFT switches, but the Contrast and Brightness knobs seem to sometimes mess with the picture. I realize the symptom is hard to explain--the picture will very suddenly (instantaneously) go dark. Colors are still visible, but very dark. It's almost like somebody stuck a really dark filter over the screen.:yes: Everything except the brightest parts of the picture are hard to see.

This set may be too new, but check and see if it has a service switch on the back. It should have two positions: normal / service.

without switching it into service mode, tap or giggle the switch to see if the picture flickers. If it does, clean that switch.

This set may be too new, but check and see if it has a service switch on the back. It should have two positions: normal / service.

without switching it into service mode, tap or giggle the switch to see if the picture flickers. If it does, clean that switch.

Yes, there is a service switch. Should I do this with the set on or off?

check it with the set on, clean it with the set off.