profdc9 ud2.7c tht question

[costas_p]

Hello, i have build the ud 2.7c tht from profdc9

in his initial post there is an image where he has not soldered the 24v regulator , as well as all the ac_to_dc components. (J2/D1/C1/C2)

In my case I soldered everything, but still choose to use a 24v switching psu.

Note: as far as i can understand the board's power supply is somewhat the same as the original SMD ud2.7c

However I find that the 24v regulator (U1) is getting warm to the touch. Isn't is supposed to not get warm at all since it does not do any job?
Is it because the D2 reverse diode supplying some voltage to the regulator ?

[alan sailer]

If you are using the external 24 volt PSU then pull the 24 volt regulator. That part is used only if you
wanted to use a 24VAC transformer to generate the 24 volts.

Just for constancy I'd pull all the ac to dc parts as well as the c1 c2 caps. I tend to not like parts on the board with no function.

I am not sure what the results of putting 24 volts on the input of the regulator chip but in you case it sounds like the
regulator is drawing current from the PSU.

Cheers.

[costas_p]

Thanks for your reply, I will remove the 24v regulator and other ac_to_dc components from the board.

Do you have any experience with the original smd 2.7c , I would like some comment if using 24v dc power supply and temperature of the 24v smd regulator. Loneocean's  website has a thermal image, but he is using a transformer so I cannot compare them, also he does not mention anything about not installing 24v regulator when using 24v dc supply.

[alan sailer]

I have used both Loneoceans SMT and profdc's thru hole version. Both without the 24 volt regulator. I have had no overheating problems. I used a 24v/2A PSU on both.

Cheers.

[costas_p]

Thanks again for the info,

the board operates fine regarding temperatures now!!

[alan sailer]

Great. It sounds like the PSU was driving the voltage regulator and heating it up.

One final note, I had to shield the driver in my DRSSTC, I suspect (with no evidence) that a thru hole UD might be more sensitive to EMI than it's surface mount cousin.

Cheers.

[costas_p]

Yes of course its gonna need shielding.

I bought the aluminum case AKG-105-46-100-ME (panels included) its made for 100x100 pcbs to be slotted, so i made another 100x100 non-copper pcb (1.6mm thickness) to screw the 97.5x97.5 driver board nicely - since i was unable to source 1.6mm thick plexi / aluminum panel

I guess someone could expand profdc9 board to make into 100x100 , but I had it made already at stock dimensions when I started my drsstc project

Also the box is 2 pieces, so it makes it easier for phase lead / ocd adjust.

[Edi]

Hm I just tested my ud2.7c driver for continuty test with multimeter and it shows 0.3 ohms at VDC+- and it sounds a beep. I don't know if that's okay.