OpenGD77

DG1YFX wrote: ↑

Wed Jan 29, 2020 10:02 pm

The diode protects the TP5100 from sudden death in case you switch off the power and the inductor produces a uncontrolled reverse polarity. I killed quite a few boards until I realized this.

73s,
Jens

LOL

OK.

so..... is it supposed to be like this ?

m1dyp wrote: ↑

Wed Jan 29, 2020 10:22 pm

so..... is it supposed to be like this ?

I think if the diode has to go anywhere it should be in series.

Otherwise you would either melt the RF choke or the diode or the PSU

like this ?

edit... pic deleted

Yes.

I think that would be OK.

I'm not really sure the diode is necessary. They normally only fit diodes in situations where people can apply the power the wrong way around e.g where people can insert a battery the wrong way around.

But in this case, it seems unlikely that the power supply would ever input voltage with the polarity reversed

I just fed my 5100 with 12v directly. YOLO!

The cap to filter seems like a nice addition though, mine does spew on VHF a bit. Within a foot or so of it while an HT is in it charging it will desense on VHF. But just a few feet away on the desk is fine so I never worried much about it.

I also put a 12V inline switch on mine so it's not running all the time, it's powered directly off my desk PSU that the mobile and HF radio run off of. A bit annoyed I put the switch in 'upside down' but I never look at the back of the charger anyway, so no biggie.

https://photos.app.goo.gl/aFbEvtMdb9D3iiTy6

Well, after some 5 blown out TP5100 I was rather suspicious. And after I put the diode in (knock on wood) not a single failure.

I've updated the picture in my blog and the forum. Quite embarrassing...

https://files.dg1yfx.de/schematics.png

73s,
Jens

nice

VK3KYY wrote: ↑

Wed Jan 29, 2020 10:32 pm

Yes.

I think that would be OK.

I'm not really sure the diode is necessary. They normally only fit diodes in situations where people can apply the power the wrong way around e.g where people can insert a battery the wrong way around.

But in this case, it seems unlikely that the power supply would ever input voltage with the polarity reversed

thanks roger, i was concerned about.....

DG1YFX wrote: ↑Wed Jan 29, 2020 10:02 pm
The diode protects the TP5100 from sudden death in case you switch off the power and the inductor produces a uncontrolled reverse polarity. I killed quite a few boards until I realized this.
73s Jens

dont want to keep buying boards when they take a week to get here

m1dyp wrote: ↑

Wed Jan 29, 2020 10:50 pm

VK3KYY wrote: ↑

Wed Jan 29, 2020 10:32 pm

Yes.

I think that would be OK.

I'm not really sure the diode is necessary. They normally only fit diodes in situations where people can apply the power the wrong way around e.g where people can insert a battery the wrong way around.

But in this case, it seems unlikely that the power supply would ever input voltage with the polarity reversed

thanks roger, i was concerned about.....

DG1YFX wrote: ↑Wed Jan 29, 2020 10:02 pm
The diode protects the TP5100 from sudden death in case you switch off the power and the inductor produces a uncontrolled reverse polarity. I killed quite a few boards until I realized this.
73s Jens

dont want to keep buying boards when they take a week to get here

Ah.

In that case the diode should actually be in parallel with the coil.