Dead Helios4 Board?

[bigbrovar]

Hi all,

I got my helios4 sometimes in 2019 and it was one of the best purchases I ever made. It has served and was solid as a rock. Unfortunately all that ended couple of days ago when I noticed the Helios was not powering up properly, think it was the power supply not connected well (because I just recently changed the location) I removed and fitted the PSU a couple of times, I could see the led light come on but still it would not boot properly.

 

By the time I found out what the real problem is things had gone worse, the reason for the incomplete boot was the SD card has been removed. Unfortunately, it seems my constant removing and refitting the PSU to the board most have done some damage because right now the board has refused to come on.

 

I used a multi-meter to check the reading from the PSU and it is constantly at 12.5v but the molex for the sata is are all completely 0v. Same for the fan ground and 12v pin for the Fan male header. Curious enough, the control and sense pin out for the FAN reads about 4v. This is pretty much the only thing I was able to get reading from. Rest of the board just seem dead, no LED, no indication whatsoever that PSU is connected to the board.

 

I am aware that the PSU was one of the weak side of the Helios4, But like I said, the pin out of the PSU reads 12.5v so I am thinking maybe this is an issue with a blown mosfet? I am a total newb when it comes to computer hardware. There are no device out there (arm based and DIY) That comes close to the Helios so I am pretty much stuck. Any advise on how to troubleshoot this would be very much welcome.

[TRS-80]

Have you tried replacing the power supply?  I can recommend Mean Well, they manufacture quality supplies at very reasonable prices.  I use them for all my SBC (and most other electronics, too).

 

Also, when you check any power supply, you need to do so under load.  Like during startup, etc.  As that is when you will see possible power dips.  Of course be careful while doing so!