Another local Hoffman! COLOR! - Page 9 - Videokarma.org TV - Video

jr_tech · #1 10-02-2022, 05:18 PM

If you don’t want to disable the instant on / vacation function, perhaps a capacitor across the B+ switch would reduce the contact degradation.

jr

Jeffhs · #2 10-02-2022, 09:58 PM

I would disable the instant-on function and be done with it. This was incorporated in color TV sets of the 1970s as an energy-saving feature (remember all the hubbub over energy conservation, not to mention the so-called energy crisis, in those days?) and practically eliminated warm-up time in TVs of the time; just flip the power switch and the picture came on almost instantly. The electricity savings could be debatable, however, since the TV's tube filaments were left on constantly, with only the B+ voltages being removed from the tubes when the set was switched off. Most TVs having instant-on had a defeat switch, either on the front panel or on the chassis rear apron so the feature could be disabled if desired, say if the TV was not to be used for an extended length of time (if the owner were on vacation, for instance, and did not want to leave the set plugged in).

If the instant-on diode, which was connected directly across the TV's main power switch, would short for any reason (say a lightning strike near the power line serving the TV), the set would remain on, regardless of whether the power switch was on or off. TVs which had this kind of damage were usually restored to normal operation simply by removing the shorted instant-on diode; however, this permanently disabled the instant-on feature, if the diode was not replaced.

Yamamaya42 · #3 10-02-2022, 11:23 PM

the "vacation switch" is in the off setting on this thing, I am not a big fan of the instant-on feature in the first place, as it tends to drastically shorten tube life, especially the CRT, but from what I have seen from other "instant-on" setups, is it not the trend to have the filaments on at like 50-60% or so and then power up to full when turned on?

But it seems that THIS set has them on full blast.

but in this annoyance, I will just get rid of the switch on the secondary side, and use the one on the primary.

jr_tech · #4 10-02-2022, 11:42 PM

Note that the primary of the power transformer is switched to a different tap in instant on mode when the power switch is off, to reduce the heater voltage.

jr

Yamamaya42 · #5 10-03-2022, 07:34 AM

That's where the SAMs info is a bit confusing, it lists no info on the 2 taps on the primary winding.

PRI 117V AC @ 3,15A, SEC.1 315V AC @.47A , SEC.2 6.3V AC @ 1.85A, SEC.3 6.3V AC @ 11.4A.

One would think that the info on the omitted primary tap would be for 150V or more to cause the heaters to run at a low enough state at “instant on.” :O

jr_tech · #6 10-03-2022, 01:17 PM

Quote:

Originally Posted by Yamamaya42

That's where the SAMs info is a bit confusing, it lists no info on the 2 taps on the primary winding.

PRI 117V AC @ 3,15A, SEC.1 315V AC @.47A , SEC.2 6.3V AC @ 1.85A, SEC.3 6.3V AC @ 11.4A.

One would think that the info on the omitted primary tap would be for 150V or more to cause the heaters to run at a low enough state at “instant on.” :O

Wouldn’t have been the first time that SAMs omitted an important piece of data.

jr

Yamamaya42 · #7 10-09-2022, 12:56 AM

Electronic M · #8 10-09-2022, 01:54 PM

Nice work.

Yamamaya42 · #9 10-15-2022, 03:45 PM

TV now n final location.

https://www.youtube.com/watch?v=Wj0a2_-IFVY

Electronic M · #10 10-15-2022, 04:01 PM

It looks good, but I can't stand the Communist News Network.

Yamamaya42 · #11 10-15-2022, 04:14 PM

Quote:

Originally Posted by Electronic M

It looks good, but I can't stand the Communist News Network.

Its one of the FEW things i can show that wont get a u-tube copyright hit T_T.

Yamamaya42 · #12 10-15-2022, 05:45 PM

I did try to put in a NOS 6BK4C, but it FAILED fantastically, throwing sparks as soon as I powered it up, the grid exploded and fried a resistor.

so I'm back on the old smoky glass tube.

http://suzaku.live-evil.org/1015220040.jpg

Yamamaya42 · #13 11-18-2022, 10:23 AM

Here is a reminder as why one should never trust weird no-named electrolytic capacitors.
This is out of a dead 6 year old LCD monitor. A ( TAICON) branded part.

http://suzaku.live-evil.org/1117222242.jpg

they don't make em like the used to!

kvflyer · #14 11-22-2022, 09:52 AM

Preaching to the choir here of course, but all the more reason to test components before using them. This is a note to myself as well. I have the equipment; I need to use it.

Thanks.

Electronic M · #15 11-22-2022, 01:31 PM

Quote:

Originally Posted by kvflyer

Preaching to the choir here of course, but all the more reason to test components before using them. This is a note to myself as well. I have the equipment; I need to use it.

Thanks.

My rule is if it's a used part check it...I typically only use used on stuff I don't care about. New never installed parts if I'm familiar with the brand I typically don't check.