Dr Ronald Stiffler SEC technology

[gyulasun]

Hi Slider,

Re on your picture size 640 you use here: as long as this forum software is not changed to a better one, you can bravely increase horizontal size up to 900 if it shows some picture details better. Alternatively, you can cut the picture edges on the left and right sides when there is not meaningful detail at those areas, this can also reduce the horizontal picture size.

Good progress on your SG build, and hopefully the AD9850 chip did not get damaged.

Gyula

[Slider2732]

I may try some of that bravery hehe
900 it is

The AD9850 has been tried on its own, on a breadboard, with an LED on the power rails to denote power. Every combination of VCC and GND, be it both or just single VCC and GND produces the shorting out.
Here's an Unlisted video that demonstrates what's going on.
https://www.youtube.com/watch?v=0EmRj5f04nY
I've contacted the seller via Amazon, requesting a replacement module.

[erfandl]

Hi all. is any replacement for PN4248 transistor ? I want to make my own Slayer Exciter circuit but PN4248 not available in my country

thanks

[gyulasun]

Hi Erfandl,
If you wish to use also a pnp type replacement,  then out of the many types there is the 2N3906 which may be available for you. These are the data sheets for it, many manufacturers produce it:
http://www.datasheetcatalog.com/datasheets_pdf/2/N/3/9/2N3906.shtml  If you have  RS Components, Mouser, Digikey, Futurlec or similar vendors, then I can look up some more types for you from the available offers. The PN4248 is a general purpose, low noise audio transistor, the latter feature is not needed here. There are two parameters that need attention for a substitute type: low saturation collector-emitter voltage and a decent h_FE of 100 or higher and perhaps you can find such locally.

Gyula

[gyulasun]

....
I've contacted the seller via Amazon, requesting a replacement module.

Hi Slider,

That is the best that can be done, unfortunately.

Even if someone starts looking for a faulty component by say carefully removing a tantalum chip capacitor which is across Vcc or lifting up the 4 positive supply pins for the AD9850 one by one, etc  the result may reveal the problem but the soldering may remain visible on the PCB and would just jeopardise any board replacement immediately.

Gyula