Hermes F3, wrong part...

User avatar
w-u-2-o
Posts: 5540
Joined: Fri Mar 10, 2017 1:47 pm

Hermes F3, wrong part...

Postby w-u-2-o » Tue Apr 11, 2017 8:59 pm

I received this email from someone who asked me to post it for them, as they are a bit shy about doing it themselves. I don't have an ANAN-10 and therefore can't report on any instability, however his findings are certainly very interesting--73, Scott

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Just a heads up. I finally tracked down a hardware instability in my ANAN-10 (TAPR Hermes board/APACHE 10W PA/Case). Symptom: random crash after prolonged period of operation. It seems that the Thermal re-settable "fuse" F3 on the Hermes board is the wrong value. The schematic shows a 2A "fuse". The BOM indicates a part# of MF-MSMF110/16-2CT-ND (indicated as a Bel Fuse part but actually Bourns). The measured current in F3 is ~1.6 amps. The part is spec-ed at Ihold=1.1A and Itrip=2.2A. The part is operating in its transition zone!

They seemed to have chosen it for its trip point and didn't look at its hold rating. My thermal camera shows it running at ~90C! Not good.

I replaced it with a 2A hold part and all is good.

This is just some info that you may want to keep in the back of your mind, if anyone is experiencing random issues with their ANAN-10.
Attachments
fmsmf-772347.pdf
(440.28 KiB) Downloaded 526 times
Sheet5.JPG
Sheet5.JPG (371.67 KiB) Viewed 11548 times
User avatar
jsm
Posts: 2
Joined: Sun Apr 09, 2017 7:35 pm
Location: Fort Collins, CO

Re: Hermes F3, wrong part...

Postby jsm » Thu Apr 27, 2017 4:31 pm

The problem is that there is no 2A hold part with the same itrip value (probably not possible). The 2A hold part has a 4A trip. So that part may run cooler and work great, but it also may not be providing the needed protection. In the HPSDR email list Phil Harman mentioned that he replaced F3 with a wire jumper. The question is whether the suggested replacement part is actually any better than a piece of wire, i.e. will it trip and protect the circuitry it is supposed to protect, or will the damage be done before it trips, therefore behaving no better than a piece of wire.
John
AC0ZG
K3IT
Posts: 1
Joined: Fri Apr 28, 2017 2:59 pm

Re: Hermes F3, wrong part...

Postby K3IT » Fri Apr 28, 2017 7:45 pm

I used PTS18126V300 fuse for F3 (3A hold, 5A trip). LT3680 datasheet seems to indicate that it should deliver 3.5A output, good enough to handle PHY 1Gbps 500 ma increase on the 5v rail? May be I'm overlooking something..
LU2FAF
Posts: 12
Joined: Sun Apr 09, 2017 4:55 pm

Re: Hermes F3, wrong part...

Postby LU2FAF » Mon Jun 24, 2019 4:35 am

any update about this ?
im using an orion mk2 , it seems mine fails when overheat
User avatar
w-u-2-o
Posts: 5540
Joined: Fri Mar 10, 2017 1:47 pm

Re: Hermes F3, wrong part...

Postby w-u-2-o » Mon Jun 24, 2019 10:41 am

LU2FAF wrote:any update about this ?
im using an orion mk2 , it seems mine fails when overheat

That's because the firmware build you are using fails to make timing on your hardware when the FPGA temperature increases. It has nothing to do with current overload of resettable fuses on Hermes or Angelia boards. Try a different version of the firmware.
User avatar
w-u-2-o
Posts: 5540
Joined: Fri Mar 10, 2017 1:47 pm

Re: Hermes F3, wrong part...

Postby w-u-2-o » Sat Nov 16, 2019 2:16 am

Additional info from Kjell, especially for Protocol 2 folks...

'Kjell Karlsen' la2ni@online.no

When the problem with Hermes not working good on Protocol 2, I tested my 3 Hermes boards and in addition to the fuse problem I also discovered that the 3,3V coming from U23 and goes to U19 (AVDDH), had a voltage drop on the input of U19 and U13, the Ethernet switch. For me it seemed to be too thin lead in the PCB so I just connected a thicker wire directly between U23 and U19. Both the 3,3V and 1,2V on U13 increased. After that 2 of my 3 Hermes boards works fine on protocol 2 up to 484 KHz sampling rate and the 3.rd also works OK on 768 KHz.
GW0DQW
Posts: 37
Joined: Sun Apr 09, 2017 4:21 pm
Location: Nr Cardiff
Contact:

Anyone in UK done the fuse update on Anan 100 ?

Postby GW0DQW » Thu Nov 21, 2019 8:57 pm

Hello there ,

Name is Chris in South Wales and I was wondering if any user in the UK has done the firmware update to use Thetis .

I have the Rev24 version , with built in Pure Signal and firmware switch fitted underneath.

I am looking for guidance on what and how to go on on the hardware up grade and firmware upgrade .

Am i right in thinking that in my case there is only one fuse to be upgraded .

Appreciate any help or tops please

73 Chris GW0DQW
User avatar
w-u-2-o
Posts: 5540
Joined: Fri Mar 10, 2017 1:47 pm

Re: Hermes F3, wrong part...

Postby w-u-2-o » Thu Nov 21, 2019 10:14 pm

Chris,

Fuse info in this topic where I moved your post to.

P2 firmware update discussions are separate and are taking place here:

viewforum.php?f=32

73,

Scott

Return to “Everything Else: Antennas, Relays, Switches, Power, Grounding, Cooling, etc.”