Re: ATU-100 Current Draw?
Hi Bret, The supply current of the ATU-100 is dominated by the number of relays that are activated and the unit does need to be powered to retain the tuning.
Each relay has a coil resistance of approximately 750 Ohms.
The measured current consumption of the PIC and OLED display is approximately 13 mA.
The voltage drop across the protection diode on the supply rail is approximately 0.7V.
Therefore the estimated supply current with respect to the number of active relays is shown below for 12V and 13.8V.  At a supply voltage of 13.8 V, the measured current of my ATU-100 is 0.27 A. This does drop slightly over time since the relay coil resistance will tend to increase. Using the default firmware, after reset only one of the relays is powered (C-Select), which is set to output.
Typically the seller specifies a maximum supply current of 0.45A, which will be the worst case and based on the minimum value of the relay coil resistance.
73, Dave
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What would be the current draw for the ATU-100 (the firmware V3.2 model with Tune, Auto, Bypass and 4-line screen) in idle? I read that the ATU-100 does not have latching relays so it must be powered on to retain the tuning.
BRET/N4SRN
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Re: Not charging and not showing ad a disk when connected to a PC
#ATU-10
Hi Mike, Very strange about the USB cable. I wonder if it is a mechanical issue or the way the USB-A to USB-C is connected. With respect to the display, maybe revert back to the previous version of firmware to see if it shows the previous behaviour. Perhaps David (N7DDC) may be able to comment on this.
73, Dave
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Re: Not charging and not showing ad a disk when connected to a PC
#ATU-10
Thank you, Dave and thank you Al.
UPDATE: I opened the box and try to check whether the USB connectors pin (i.e. from inside) was reading 5V. I did not. So, before assuming that it got detached from the PCB, I tested every single USB-C cable I have.
I found that with one USB-C to USB-A, it works. I cannot figure it out why as there is no logic (Murphy's law at its best).
Upgrading to 1.6, I now have every "." character replaced by a "box" character (i.e. both during the splash welcome screen and during operation). Another mystery.
Thank you for having shared your thought and help!!
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Re: Not charging and not showing ad a disk when connected to a PC
#ATU-10
Hi Mike, I do not have an ATU-10, but looking at the schematic it sounds like the USB power may not be present. This feeds the charging circuit and the PIC associated with the USB interface. The 5V from the USB interface is connected via a PTC fuse. If possible, try to check if there is 5V getting into to the unit from the USB interface and check the soldering on the USB connector.
73, Dave
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Re: Not charging and not showing ad a disk when connected to a PC
#ATU-10
The unit works fine. It is only the charging and the PC connectivity that (apparently) fail.?
Is this indeed your experience? I would have guessed that a faulty PIC would result in no operation whatsoever of the device... Could I be wrong?
73 de Mike
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Re: Not charging and not showing ad a disk when connected to a PC
#ATU-10
Michele
I had this same thing happen a while ago. The problem turned out to be poor soldering of the PIC. Fortunately, I have a hot air rework station and was able to fix it.
73 - Al, K2ZN
On Sat, Apr 22, 2023, 07:06 Michele (Mike) - iv3ifz < mgiugliano@...> wrote: I bought a new ATU-10 months ago and I immediately upgraded its firmware to 1.5, ?but did not use the unit since then.
I would now like to fully charge the battery as well as to upgrade to 1.6 firmware. The unit powers up correctly, but nothing happens as I plug the USB-C cable to the unit and to a charger (25W). Nothing happens when I connect the unit to my laptop (Mac): no "USB disk" appears as mounted. The same happens with another USB cable.
Could the unit (or the USB connector) be damaged? Am I forgetting something (e.g. how to put the unit in "programming mode" or in "charging mode") ? Thank you for your patience with my question.?
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Not charging and not showing ad a disk when connected to a PC
#ATU-10
I bought a new ATU-10 months ago and I immediately upgraded its firmware to 1.5, ?but did not use the unit since then.
I would now like to fully charge the battery as well as to upgrade to 1.6 firmware. The unit powers up correctly, but nothing happens as I plug the USB-C cable to the unit and to a charger (25W). Nothing happens when I connect the unit to my laptop (Mac): no "USB disk" appears as mounted. The same happens with another USB cable.
Could the unit (or the USB connector) be damaged? Am I forgetting something (e.g. how to put the unit in "programming mode" or in "charging mode") ? Thank you for your patience with my question.?
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Re: ATU-100 not working / matching in "High Bands"
Thanks a lot Dave for taking the time to share your experience.? I can see you want this for QRP use. In my case, I want to work this as a remote ATU in LOW power. I have already bought the right diodes and I will make the upgrade as soon as I receive those. Am also building pair of Bias-tee to bring the power to the unit and this will feed a "Y" dipole - 40m made with fishing rods. If I succeed with this project I will share some pictures.?
Thanks to Dave and all and hace a great weekend!.
73s Anibal DM5MT?
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Re: ATU-100 not working / matching in "High Bands"
Hi Anibal, The ATU-100 that I received also had the same diode arrangement to that shown in your picture, one was marked ¡°SA¡± which is a 1N5711 and should have a similar specification to the BAT41. I swapped both diodes for BAT41, since the compensation values used in the firmware are based on BAT41¡¯s.
I am using the ATU for QRP and wound the Stockton bridge with a 5:1 ratio and updated the constants in the EEPROM accordingly and it seems to work fine up to 30MHz.
Using the Nano-VNA, and manual selection of L and C, the measured and simulated (SIM) results for a best match with different resistive loads is shown below.
The measured and simulated results are similar. At low C values, stray capacitances is the likely reason to require the selected C to be set to zero.
73, Dave
 At low frequencies, the Stockton bridge will present a low impedance to ground, producing a high SWR as expected. ?
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Re: ATU-100 not working / matching in "High Bands"
Have you tested the tuner with a dummy load, to see?if the power is different the higher you go in frq, It looks like it should be ok with the BAT41, Dave
Hi Guys, I have recently bought the kit and built it up. Now I am testing it and this is nicely working from 17m to 160m (it reads SWR and does the matches?accordingly) but this is "doing nothing" for 6, 10, 12 and 15 meters,?neither read SWR nor does the matching.
?
I understand the unit can get damaged but this si extrange since this is "partially working" in some bands.
?
Any hint / advice?
Thanks in advance!
Anibal Dos Ramos, DM5MT
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Re: ATU-100 not working / matching in "High Bands"
Hi? I had bad power and swr reading in the higher bands? Then I fitted the bat 41 in to both D1 and D2 and it is working fine,? This is very common with this tuner, it looks that they have fitted cheap silicone diodes, these are just used as rectifying diodes so the pic see's DC voltage, from the tandem match transformer, Dave 2E0DMB?
Hello Dave, I just gave a look into the diode type. Waht I can see is they are both completely different one from another. What I have seen before when it comes to swr metters is "to have 2 Germanio diodes", one for the forward and other for the reflected. I will buy the one you mentioned and I will replace them. Thanks a lot!
Hi? Change D1 and D2 to Bat41 diode's Dave
Thanks a lot Dave for your prompt repply!!!
It could be the reason but those are "already mounted" (SMD), right? is there any replacement / retrofir to fix that one?
Any action needed from my side?
What are the right ones?
Thanks!
Anibal
DM5MT
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Re: ATU-100 not working / matching in "High Bands"
Hello Dave, I just gave a look into the diode type. Waht I can see is they are both completely different one from another. What I have seen before when it comes to swr metters is "to have 2 Germanio diodes", one for the forward and other for the reflected. I will buy the one you mentioned and I will replace them. Thanks a lot!
Hi? Change D1 and D2 to Bat41 diode's Dave
Thanks a lot Dave for your prompt repply!!!
It could be the reason but those are "already mounted" (SMD), right? is there any replacement / retrofir to fix that one?
Any action needed from my side?
What are the right ones?
Thanks!
Anibal
DM5MT
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Re: ATU-100 not working / matching in "High Bands"
Hi? Change D1 and D2 to Bat41 diode's Dave
Thanks a lot Dave for your prompt repply!!!
It could be the reason but those are "already mounted" (SMD), right? is there any replacement / retrofir to fix that one?
Any action needed from my side?
What are the right ones?
Thanks!
Anibal
DM5MT
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Re: ATU-100 not working / matching in "High Bands"
Thanks a lot Dave for your prompt repply!!!
It could be the reason but those are "already mounted" (SMD), right? is there any replacement / retrofir to fix that one?
Any action needed from my side?
What are the right ones?
Thanks!
Anibal
DM5MT
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Re: ATU-100 not working / matching in "High Bands"
Hi? I think you may have the?wrong diodes fitted for the tandem match, Dave
Hi Guys, I have recently bought the kit and built it up. Now I am testing it and this is nicely working from 17m to 160m (it reads SWR and does the matches?accordingly) but this is "doing nothing" for 6, 10, 12 and 15 meters,?neither read SWR nor does the matching.
?
I understand the unit can get damaged but this si extrange since this is "partially working" in some bands.
?
Any hint / advice?
Thanks in advance!
Anibal Dos Ramos, DM5MT
|
ATU-100 not working / matching in "High Bands"
Hi Guys, I have recently bought the kit and built it up. Now I am testing it and this is nicely working from 17m to 160m (it reads SWR and does the matches?accordingly) but this is "doing nothing" for 6, 10, 12 and 15 meters,?neither read SWR nor does the matching.
?
I understand the unit can get damaged but this si extrange since this is "partially working" in some bands.
?
Any hint / advice?
Thanks in advance!
Anibal Dos Ramos, DM5MT
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Paul,
One device show 1, second one 3, someone is wrong.
Put a 50 Ohm load instead of antenna and check if both show 1.
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Re: ATU-10 in Assembled PCB form
sorry forgot the picture. 
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Re: ATU-10 in Assembled PCB form
Bob,
I have an assembled N7DDC ATU-10 PCB here which is available. It is programmed with V1.6 firmware (latest) PCB only as shown, no battery, case or OLED display.
I think a fair price is around US$50 plus shipping.?? As you are probably aware, shipping these days can get expensive. I don't have an actual cost but would guess should be under about US$20
Glenn
vk3pe
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Al Scanandoah
