Classic Arduino no high voltage

More
9 months 2 weeks ago #7989 by i_like_old_tat
Hi all

my wife got me a classic Arduino for Christmas '16, however due to ill health and other problems I've only just got round to assembling it.

I assembled the low-voltage side, no problems. I then assembled the high-voltage circuit but I only have 11.8v at the test points. All components are correctly installed with regards to value and/or polarity - I'm using a 12v regulated supply, and 12v goes into the 740 MOSFET centre pin, but there is no voltage present on the other two. I also tried connecting a tube directly to the HV test points (both polarities) but it didn't switch. All components on the HV side either show 11.8v or 0v.

I have a steady 5.1v at the Arduino socket's pin 1 - would I need to install the Arduino and do a reset or do you think I have a faulty MOSFET or other component?

Regards,
Glen

Please Log in or Create an account to join the conversation.

More
9 months 2 weeks ago #7990 by Ty_Eeberfest
You last sentence has me confused. Is the chip installed in its socket or isn't it? Without the chip there will be no high voltage since the chip is what runs / regulates the HV power supply.

Look into it later when the dust is clearing off the crater.

Please Log in or Create an account to join the conversation.

More
9 months 2 weeks ago #7992 by i_like_old_tat
Thanks for the input, I've been away from home past couple days. I had previously run it with both the Arduino in the socket and out of it. I re-installed the Arduino chip this afternoon, rechecked my soldering and I got an improvement on voltage, but not 170v or higher (it fluctuated between 70 and 100v).

Changed all the components of the HV system one by one until I got a good HV supply. The MOSFET was a bit iffy, once I had changed it, a steady 380v! And better still, nothing gets too hot. Will still heatsink the 7805 and MOSFET anyway, I have plenty of spare aluminium from laptops and computers I have dismantled.

Will post some pictures when I have completed it, just waiting for the tube sockets to arrive now...

Please Log in or Create an account to join the conversation.

More
8 months 3 weeks ago #8023 by Ian
Sorry to hear about the bad MOSFET. It seems a constant that a few percent are not hitting the mark.

The firmware was also changed recently to have a startup sequence which holds the generation steady, by removing all the other variables (e.g. LDR, modulation) to help locate these cases quickly.

Please Log in or Create an account to join the conversation.

Moderators: AccutronTy_EeberfestIan
Time to create page: 0.037 seconds

Search

Tube Suppliers

Go to top
JSN Boot template designed by JoomlaShine.com