12v Power Pack - HEQ5 Pro

[Clarkey]

20 minutes ago, Carbon Brush said:

The problem here is inrush, not steady stste current

I appreciate that it is not steady state current, but to draw more than 5 amps even at start up still seems excessive. Without any other demand the mount takes very little and I'm not sure what would take it above 5A. Having said this, the quality of SW soldering leaves a lot to be desired so who knows what "special" load they have added😂

[wulfrun]

46 minutes ago, Clarkey said:

I appreciate that it is not steady state current, but to draw more than 5 amps even at start up still seems excessive. Without any other demand the mount takes very little and I'm not sure what would take it above 5A. Having said this, the quality of SW soldering leaves a lot to be desired so who knows what "special" load they have added😂

Wouldn't surprise me one bit. A single moderate-value (470uf) electrolytic capacitor has an ESR in the tenth of an Ohm range and that's all that limits the 'surge' at switch-on, other than wiring and pcb-track resistances. It would therefore like to draw about 12/0.1=120 amps, albeit very briefly. Admittedly, pcb & wiring will add resistance so it'll not be anywhere near in reality. However, a sprinkling of decoupling capacitors dotted around a board (highly likely) means that a lot of electronic gear, even low-voltage gear, can have inrush currents in the tens of amps. Enough to blow a quick-blow fuse for sure.

Edited September 3, 2022 by wulfrun

[Clarkey]

Fair enough. I shall bow to the superior knowledge of @Carbon Brushand @wulfrun.

As a chemist I shall crawl back in my hole🤣

[wulfrun]

16 minutes ago, Clarkey said:

Fair enough. I shall bow to the superior knowledge of @Carbon Brushand @wulfrun.

As a chemist I shall crawl back in my hole🤣

I'll let you into a 'secret'...I was an industrial chemist in a previous career, so my qualifications are in chemistry too! Electronics though, has been a 50-odd year hobby so I've studied that (non-academically) probably more than I ever did for my chemistry qualifications. No need to crawl back in any hole, you probably have knowledge in areas that would baffle me.

Edited September 3, 2022 by wulfrun
grammar

[bosun21]

This is a carbon copy of what happened to my EQ5 pro mount, albeit I was using my Nevada PSU when the 5A fuse blew in the cigarette plug. I ran the usual gamut of electrical tests and found nothing (much like yourself). I was advised to replace the fast blow fuse with the slow. My mount is now running and tracking without issue. It sure looks like inrush is most definitely the cause. Good luck.

     Ian 

 

     
 
 

Edited September 3, 2022 by bosun21
Typo