Controlling external HDD power from the DVB-T tuner

When the capacity of the USB stick attached to the tuner ceased to be enough for me, I connected an old 2.5 "disk. When it was too small, I connected a 3.5" HD disk. There is a power problem. The power supply and disk had to work all the time when I set to record my favorite program. Almost every tuner has a SCART output, on which pin 8 informs about turning on the tuner. Why SCART Because, depending on the tuner, the USB voltage can always be on SCART when the tuner is active, because this pin controls the TV by switching it to the selected video input.
Zasilanie_...ev1337.pdf Download (11.96 kB)

The simple design that I made allows you to switch on the hard disk power supply or the 12V voltage alone. In addition, it contains a stabilizer that produces 5V. Connections on JP1 decide whether the power supply activation signal should be USB voltage from the tuner or SCART connectors. In addition, you can choose whether 5V for HD should come from the tuner or U1 stabilizer.

The SCART and USB connector is through. Due to the fact that I do not use SCART, I did not solder the through connector. In addition, the heat sink is a bit disturbing (as I designed the PCB, I was young and inexperienced).

The construction is not very successful. The line stabilizer can give off a lot of heat. At a consumption of 0.8A, almost 5W will separate on the stabilizer. With more economical electronics it is better, 500mA is 3.5W. Undoubtedly, a pulse stabilizer would be better.
Another disadvantage, disk or tuner, is that the hard disk needs some time before it is ready to work. If the tuner briefly waits for the drive to be ready, it may not be visible to the tuner. A problem known to some Amigos.

If necessary, I will generate PCB drawings in PDF or Gerber.

If the tuner loses recording, will the disk be able to turn on (accelerate)?

And did your colleague read the whole thing?

LChucki wrote:

Another disadvantage, disk or tuner, is that the hard disk needs some time before it is ready to work. If the tuner briefly waits for the drive to be ready, it may not be visible to the tuner.

lukiiiii wrote:

As the tuner losses with recording, the disk will turn on (accelerate)

Is it a question or a statement? Unfinished sentence so I don't know.

What is the purpose of this construction? Disks don't like to be turned on / off without need. I don't think anything kills them anymore.

glazikx wrote:

Disks don't like to be turned on / off without need.

And in such a DVD, computer etc. discs work 24 / h regardless of whether the computer is turned on or not?

glazikx wrote:

What is the purpose of this construction?

Energy saving and HD mechanics.

But in the case of timer recording settings, this design will not work, because the tuner does not start in normal mode -> displaying the image on TV.

bigthomas666 wrote:

But in the case of timer recording settings, this design will not work, because the tuner does not start in normal mode -> displaying the image on TV.

My just turned on the signal on SCART. If the tuner doesn't do it, maybe it turns on 5V on USB?