Hermes Fail to Start

[Prem]

Hi All,

My Hermes sometime fail to boot. When I push power switch, both front Panel LED lit steady (Status LED not blink as usual). All power LED inside Hermes lite. None of diagnosis LED lite. This I face sometimes. Later after sometime when I restart Hermes, will boot as normal. What could be wrong ??

I power my Hermes from external 13.8V and so 12V and 5V are generated in Hermes itself.

73s

Prem,

[Prem]

This morning without touching anything further, my Hermes started as normal.
So is it anything connected to temperature ?
I have fixed heat sink for FPGA, all power reg IC, LAN chip and ADC chip.

A small 12V fan on top of my box which exhaust inside air out. Also holes on bottom side of box in an intention to have inlet air to box.

Any chip have internal shutdown feature based on temperature ?
My fan switch on/off with Hermes power switch. Means fan off if Hermes power Off.

Running time FPGA heat sink come around 50 deg C and with fan almost 8 deg come down.
Rds,

Prem

[Prem]

Hi Scott,

Any trouble shooting steps to advise on this trouble ??
Now also I get this fault. Fail to boot.

Rds,
Prem

[w-u-2-o]

Prem,

The list of things that could be wrong is so very, very long, so I can't even begin to guess. However, if you think it is thermally related, there are 3 PTC type resettable fuses on the board, F1, F2, and F3. You could check those. If you thermally damaged a chip then it could be hard to find.

Good luck!

Scott

[Prem]

Hi Scott,

Since the issue come even morning time try, after a long sleep at night, it is not a thermal issue !!
Once it started, it will run trouble-free for hours.
I did even Tx yesterday with SSB as well as FT8 digital mode.

Anyone have experienced similar trouble, please share our experience in fault finding.

Possibly some dry connection some where ? !!

73s,

Prem

[Prem]

Hi Scott,

Now the LED On are : LED6 (D13) - " Lights when PHY transmit ethernet traffic "
LED10 (D16) - " Lights when a Hermes discovery packet reply is sent"
All Five power LED and front Panel power LED


Any advise on further trouble shooting on boot failure ?

73s,
Prem

[w-u-2-o]

I'm sorry Prem. If it is a hardware fault, again the list of possibilities is enormous. There is no way I could begin to even guess.

73,

Scott

[Prem]

Hi Scott,

is there any one else who can be approached at this stage ?

Any suggestion ?

Rds, Prem

[w-u-2-o]

No suggestions other than to send your board to someone else who has built their own Hermes and who has the required hardware debugging skills to debug it for you. Obviously it will require careful inspection and analysis of the many signals on the board to isolate the problem.

73,

Scott

[Prem]

Hi Scott,

I was trying to see if any dry soldering between FPGA pins, also did a clean with solution between pins. Now it run ok !!
So it is some dry or short between FPGA pins. Let us see if the issue come again .

73s

Regards,
Prem , A65BK/VU2OLU

[w-u-2-o]

Great to hear, Prem! When you build your own boards you are also your own quality control

I bought my own inexpensive assembly/inspection microscope from Amazon in order to avoid those sort of problems. It was money well spent, as it no doubt has prevented many such occurrences on my own projects.

73,

Scott

[Prem]

Hi Scott,

please share the product link you bought.
I have one as seen in below link. but not help me to solder while viewing.

http://www.engtaobao.com/item/taobao/41885659345.html

73s

Prem

[w-u-2-o]

This is what I use:

http://www.amscope.com/10x-20x-led-bino ... light.html

I would have preferred a zoom microscope, but this one works pretty good.

73,

Scott