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

Yamamaya42 · #**121** 09-13-2022, 12:44 PM

The EDI Solid-Tube R-3DS3... FAILED!

After about 2 hours of total combined test runs, started to lose brightness and horizontal width, removed it, it was slightly warm at the base, and put the glass 3A3C back in, and all was back to normal.

Guess ya just can't trust any solid HV rect in a color set.

Yamamaya42 · #**122** 09-17-2022, 06:18 PM

compromise to leaving the HV cage cover off.

http://suzaku.live-evil.org/0917221801a.jpg

Fan will be paced on the back cover.

Yamamaya42 · #**123** 10-02-2022, 03:58 PM

The power switch in this thing is staring to annoy me.

I have N0 IDEA why the hell they did this, as is was redundant and just causing problems as the contacts are burned due to the 300+v.
cleaning does not help for long, it looses brightness and width, rapid on/off brings it back.

http://suzaku.live-evil.org/hoff-switch.jpg

will most likely bypass it.

Electronic M · #**124** 10-02-2022, 05:01 PM

If you haven't disabled instant on then you will if you short the B+ power switch.
I think the idea of the B+ switch was to keep the B+ off when the set was turned off to the instant on state...it would reduce power consumption when "off" and prevent the set being in a state where the sweep oscs weren't running but the outputs had power and could potentially draw excessive current.

jr_tech · #**125** 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 · #**126** 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 · #**127** 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 · #**128** 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 · #**129** 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 · #**130** 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