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PostPosted: Sun Sep 10, 2017 1:32 am 
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Joined: Sat Jul 20, 2013 11:00 pm
Posts: 22
Hello Jim and group,

I have HR50 #1119, with a rev. E RF board, rev. C ATU and a splash screen which reads: F: 3.0D, ATU 1.3 HW:E

It's worked just fine until I started some maintenance on it yesterday: I reset the bias to 150mA per MOSFET (which went very smoothly) and then soon after, tried to update the ATU firmware from 1.3 to 1.4.

I'm using MikroBootloader v 2.3 with the latest Microchip drivers and PIC18 selected. I can connect the MikroBootloader to the amp successfully and do an amp firmware update, but I'm not able to complete the ATU firmware update: In the sequence, I get as far as HR50 menu item 10 <Update Firmware> but at that point, the MikroBootloader can't reconnect to the amp to proceed further - it returns the error: "Unable to open Com port: Com 9 ", so I can never get as far as selecting the ATU 1.4 hex file to do the update. I've been following the instructions in the ATU manual. I've tried this on 2 machines, one running W 8.1 and the other 7, but same problem with both.

I wondered whether there might have been some corruption in the amp firmware, so I then went ahead and reinstalled first v 2.0B and then 3.0D again. That process went smoothly and the amp and computer communicated flawlessly, but I'm still stuck at <Updating Firmware> when I come to try to install the ATU firmware update.

So today, I was using the amp and noticed that now, the amp is putting out a max of 7W on 17m and above, while it delivers the full 50W output on 20m and below. The tuner appears to be working and is tuning on the bands with the low output. Could this be a problem with the firmware selecting the amp's LPFs or is it related to the ATU?

I took the amp apart and had a careful look at the cable connections to make sure I hadn't disconnected something doing the bias adjustment, but all appears good there.

So, where do I look next, firstly to restore my output on 17m & up and then to be able to update the ATU firmware?

I'm not sure how this happened.

Any ideas gratefully received...

73,
John
VK7JB


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PostPosted: Mon Sep 11, 2017 6:34 am 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Hi John,

Sorry to hear that you are having trouble with your amp. "Unable to open comm port" sounds like more of an issue between the Bootloader and the PC not anything to do with the ATU. For some reason, if you plug the amp into a different USB port it enumerates and as a different comm port. I recommend plugging in the USB and powering up the amp then looking in Device Manager -> Ports for the amp and trying the bootloader again making certain the port is correct.

As for low power on 17 and above, the issue is most likely RLY12, RLY13, RLY14 or RLY15 either stuck on or not switching in. These relays switch in C5, C7, C31 and C33 as needed on 30 - 10M in various combinations. The way to test is turn the amp off and you should see an open circuit on the relay side of C5, C7, C31 and C33. If any of these conduct with ground, the associated relay needs to be replaced. To make sure that they are pulling in correctly, turn the amp on select 30M, key and unkey the amp (to set the relays) then check for a short to ground on the relay side of C5, C7, C31 and C33 these all should now show a short to ground, if not the associated relay should be replaced.

In my experience, the symptom you are describing indicates that one of the relays is always on. Probably either RLY12 or RLY14.

73,
Jim WA2EUJ


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PostPosted: Mon Sep 11, 2017 9:29 am 
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Joined: Sat Jul 20, 2013 11:00 pm
Posts: 22
Thanks Jim for such a prompt response.

The band switching problem has become intermittent and occurs whether I'm auto-bandswitching via the KX3 or changing bands manually. I'll dig down and check those relays, but it may be difficult to pin down the cause if it's intermittent. I'll see what I find.

The bootloader issue is frustrating to say the least. The COM port is enumerating correctly and is briefly listed there in device manager while the amp is booting. Bootloader is successfully connecting via that port and is able to do an amp firmware update just fine. The problem is that the connection to the port is lost after the amp completes it's boot sequence and then can't be reconnected when I try to do an ATU firmware update. After the amp boots and the splash screen goes, the amp closes the COM port connection (I hear the windows sound telling me it's dropped the amp connection), and the bootloader can't reconnect after I've selected menu item 10 to do the atu firmware update because the COM port connection has been dropped by then
.
It's odd this is the same with both my PC's I figure it's something I'm doing incorrectly in the sequence but I don't know what. I'll persevere when I get a little more time.

Thanks again for your help.
73 - john


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PostPosted: Mon Sep 11, 2017 8:14 pm 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Oh I remember now, on the older amps there's only one com port running to the rear panel it goes to both the Microchip USB-TTL converter and the ACC jack to connect the KX2/3. If you go to the menu and set KX3 mode off and the serial port to 19200, it will stay connected to the PC.

Jim.


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PostPosted: Tue Sep 12, 2017 12:52 am 
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Joined: Sat Jul 20, 2013 11:00 pm
Posts: 22
Hi again Jim,

Well, that fixed the problem with the COM port: I turned KX3 mode off and the port remained open and then, with great relief, I could
do the ATU firmware update - perfectly, first try. I'd never have guessed that solution and I couldn't find any reference to it anywhere in the online documentation for the amp or ATU. I've written it down for future reference! :P

Now I'll take another look at those relays...the only new thing I've noticed there is that the auto-band changing through the KX3 takes longer, it's kinda sluggish = I change bands and there's a ----d-e-l-a-y-- before the band change is registered on the amp's LCD. Not sure of the relevance of that, if any.

Thanks again for your help!

John


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PostPosted: Tue Sep 12, 2017 3:53 am 
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Joined: Sat Jul 20, 2013 11:00 pm
Posts: 22
I opened the amp and did some probing and Relay 14 is the problem. The fault is intermittent, but it produced itself several times during testing which was very convenient and made things clearer.

With the fault present and the amp powered off, C31 shows short circuit to ground on the relay side, while C33, C5 and C7 are all open circuit to ground. With the amp powered on and tuned to 30m, C31, C33, C5 & C7 are all shorted to ground.

When the problem spontaneously resolved itself, with the power off, the relay side of C31 was open circuit to ground, as you'd expect.

So relay 14 is intermittently sticking in the ON position.

I'll swap it out soon. I'm pretty sure I can find these NEC 12V 2A relays through a local supplier.

Thanks again Jim.

73,
John


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PostPosted: Tue Sep 12, 2017 5:25 am 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
There are several relays that will fit that application. It's a DPDT DIP relay with 10 pins and a 12V non-latching coil. Contact rating 2A or greater only the carry current is important because the relay is never switched hot.

The sluggishness that you are seeing is in the KX3 which takes up to 4 seconds after a band change to send the command. The HR50 acts on the command in a few milliseconds. Maybe if you tip the KX3 so the ACC jack is pointing down, the data will come out faster, like a bottle of Ketchup.

There are very few amps that require turning off KX3 mode to update the ATU so I guess that aspect slipped through the cracks on the documentation. We have just redesigned the rear panel with a FTDI USB chip for 'no driver' implimentation and the serial port is opto-coupled to prevent noise, RFI and ground loops primarily in SDR's, and it has separate serial ports for the ACC jack and the USB.

As soon as our Webmaster recovers from Hurricane Irma, we'll put them on the website for folks who want to replace their rear panel PCB.

73,
Jim WA2EUJ


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PostPosted: Tue Sep 12, 2017 7:57 am 
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Joined: Sat Jul 20, 2013 11:00 pm
Posts: 22
The re-designed rear panels sound great and I'll order one when you put them up for sale.

I managed to find some NEC EA2-12NU's from a supplier in Sydney. I bought a few - just in case.

I did wonder if the delay was in the KX3. I'll try your trick and if it doesn't work I'll give the KX3 a vigorous shake and squeeze before I change bands. :lol:

I love the KX3- HR50 combo btw. It travels far and wide with me and keeps me on CW, data modes and phone. I reach for it ahead of my K3 often. I'm thinking of building another HR50 just for the fun of it and because I'd really like the QSK board which won't fit in my old amp with the ATU installed.

73,
John


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PostPosted: Mon Sep 18, 2017 3:03 am 
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Joined: Sat Jul 20, 2013 11:00 pm
Posts: 22
Hi Jim,

Just a note to complete the loop and let you know that I replaced relay 14 on the amp board today and the band switching is back to normal function. I'm very pleased. Thanks for you help with the diagnosis. Much appreciated.

73,
John


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