VHF Tuner Alignment: where is the overall oscillator adjustment?

[Yamamaya42]

Since we both seem to have the same Maggie chassis TVs, and even same copies of the SAMS for it with the red writing on it, any idea what the omission of the AFT switch is about? It has the “Chroma Tone” as listed on the SAMS, but where SAMS has AFT disable on the back, mine has “Auto Color off/on” and can find no info about it on the SAMS. :/

[zeno]

AFT was often an upgrade you paid for.

When you work on a set both the AFT & any auto color switches should be off.
Tuners have AFT off switches to turn it off for a second at channel change.
Those are on the side or rear of the TNR assy. Also some had a switch up
front of TNR to defeat it when fine tuning is engaged. Generally you can
defeat the AFT by grounding the TNR aft pin.
Keep in mind both the AFT AND auto color may have AFT on/off on them.
When done you can put the AFT back on, it does work good.

Chroma Tone was Maggys auto color scheme. In the day we called it the
" brownilator". When on it gives an overall puky brown cast to the pix.
Leave it off for best pix.

73 Zeno
LFOD !

[LukeSimon]

Originally Posted by Yamamaya42

Since we both seem to have the same Maggie chassis TVs, and even same copies of the SAMS for it with the red writing on it, any idea what the omission of the AFT switch is about? It has the “Chroma Tone” as listed on the SAMS, but where SAMS has AFT disable on the back, mine has “Auto Color off/on” and can find no info about it on the SAMS. :/

Your T933 doesn’t have an AFT switch on the back? Mine has the switch. It is labeled “auto color” on the TV, but it is really just the AFT defeat switch.


The issue I am struggling with is chroma bleeding, smearing, or streaking. I have a T931 too, which is almost identical. So I know how the tuner should behave: turning fine tuning counterclockwise increases sharpness and turning it clockwise increases smearing. That is how my T931 fine tuning works, and quite frankly all of my 1960s work that way.

My T933’s fine tuning has increased smear when turning clockwise, as expected, but counterclockwise doesn’t decrease the color smear to a sufficient level. When I turn the chroma gain to minimum, there is no smear in the black and white.

Also, the fine tuning doesn’t “wrap around”. So if I continue turning it counterclockwise it seems to rotate to one extreme and not circle back to the other extreme. Any ideas as to what is wrong?

[zeno]

On newer tuners the FT has a set range. Usually if you say
put it on ch 6 you can tune UP to FM radio or DWN to ch 5.
So yours is normal.

Old tuners had 12 screwdriver holes on the front of the TNR and
one FT coil. To adj center coil then adj the channel for best pix.

Zeno

[LukeSimon]

Originally Posted by zeno

On newer tuners the FT has a set range. Usually if you say
put it on ch 6 you can tune UP to FM radio or DWN to ch 5.
So yours is normal.

Old tuners had 12 screwdriver holes on the front of the TNR and
one FT coil. To adj center coil then adj the channel for best pix.

Zeno

So it is normal that the FT doesn’t wrap around, but the fact it can’t FT fully away from smearing color is still a real issue. Any suggestions on what to try for fixing this?