Hello Everyone,

Thank you guys so much for spending your time and helping me.

Hoped to find an easy solution for my focusers but didn’t happen.

This morning found another fault – the 12V regulator (OKI-78SR-12/1.0-W36-C) was in place but  has gone by an known reason ( regulated voltage was about 4V measured on AXIS 4 VMOT pin)- maybe because I used a power supply ( 24V) even that the voltage wasn’t the reason. So, found locally another one ( Vreg MC78T12 [12 V & 3A Output]) and replaced but still  no success with AXIS4.

Thanks to George and Haward for your time- I read carefully your messages but couldn’t find an immediate solution.  So here are few things I looked at:

1. For AXIS1 & AXIS2 used LV8729 : voltage on EN pin measured on both drivers  and on  IO12 shown Low ( measured related to the ground - ~ 0V) while on AXIS4 – EN pin has shown high ~3.26V as well as on IO4 relative to the ground) . So, properly working drivers have EN (Low) and Not working AXIS4 ( Focuser) has ~3.3 V on its EN pin.

 Is this means that active state on the LV8729 driver should have EN  Low?

1. VDD voltage for all drivers was measured ~ 3.25 V, VMOT for all drivers measured shown between  11.75V(Regulated  going to AXIS4)  < U <11.9 V ( Not regulated going to AXIS1&2)
2. AXIS4 has also LV8729. Attempted to detect High/Low states ( as Ken suggested)  of DIR pin related to the ground for  all three drivers: on AXIS4 using SHC  and moving the focuser :no change of state was found, In AXIS1&2 : changing directions from SHC of RA & DEC  (<-…….o……..+>) produced  noticeable  changes of  amplitude of voltage (~ 2.5 V) in each direction

I don’t have an oscilloscope to measure the pulses.

For enabling AXIS4 I placed a jumper on “T” jumper section  (AUX2) so  EN  pin of AXIS4 driver get  connected to IO4 in ESP32.

I see the problem that IO4 sent High to EN pin and disactivate the AXIS4 ( Please correct me if I am wrong).

So, is there any way to enable AXIS4 driver in this situation?

Thanks for your help.

Plamen

On Tue, Aug 10, 2021 at 10:37 AM, George Cushing wrote:

IIRC if you are using LV8729 drivers or others that have EN be pulled high

Were these drivers requiring EN pulled HIGH to become enabled (a rather rare situation) it seems impossible they would have worked with other designs (as was the case evidently) without Dimitrov realizing a special OpStep setting had to be used.

On the other hand if they are like typical drivers needing EN pulled LOW to enable, AND they didn't happen to have built-in pull down resistors, that might do it.  But then he mentioned jumpering Aux2 to control EN on Focuser1 and that would have resolved the problem were this the cause.

All I can say is that my (MKS I think) LV8729's (and DRV8825, A4988, TMC2100) work fine with my MaxESP3 in the focuser/rotator sockets.

BTW the EN pins are left floating because...

• Easier assembly vs. adding pull-down resistors.
• The TMC2100 does standstill power reduction when its EN pin is floating, which is a nice option for a board without the spare pins for EN control.

I had an error in the Wiki (and my understanding at the time) where I suggested TMC2208's are best (for the same reason) but really they don't behave like TMC2100's in this regard.  So I updated the Wiki to place the TMC2100 back as the best option.  In theory some TMC2130's (the non-SPI) "DIY" aka stand-alone versions should behave just like TMC2100's though I've never experimented with that.. and with users mentioning the Vref voltages not being correct on these I would like to see this solution verified before recommending them.  That would be nice as TMC2100's are harder to come by.

I *may* have found the short. Because the short was intermittent, I picked up the board for yet another inspection, and when the short went away again. I tapped the board on my work bench and lo and behold, a 1/8^th inch strand of wire appears from nowhere. I don’t know where it came from – could have been on my bench, I suppose. Could have been in the box I had stored all the components in. Dunno, but as of this moment, the short is gone. Yea!

Now, as to the Teensy power “issue” and separating Vin from VUSB, I was looking for the wrong thing – I thought there would be a nice, golden bridge between the pads. But it’s the trace I need to cut. So, this is likely the issue, and seeing that, I am excited!

Thanks very much!

Sent from Mail for Windows

Thank you!

My target mount is a CG5-class, either an LX70 or a Exos2 – I have both.

As for motors, I have a variety, some Nema 14 and others Nema 17. However, I am thinking of what to do now *before* attempting to connect motors, like adjusting the Vref pots, that sort of thing.

The first time I powered on the OnStep, it was without any of the plug-in boards. The power LED lit.

The second time was with the Teensy and Wifi module. Both power and STA1 LED lit.

Plugged in USB cable from Teensy to PC – PC powered off.

Unplugged power. Removed Teensy from OnStep. Rebooted PC. Plugged Teensy USB into PC – all is well. Programmed Teensy.

Thought I read something about downloading firmware to WiFi module, so connected that to PC via USB. Nada. Determined WiFi module dead. Connected replacement to USB and PC. Familiar ding. Determined I didn’t have to muck with the firmware after all.

Put Teensy and Wifi module onto OnStep. I also had the TMC2130’s installed in preparation for tweaking their Vref. Unfortunately, something went wrong and I ended up with a blown fuse.

I have checked the board for shorts, and thought I might have possibly found one which I removed. The Teensy is okay (still reports OnStep when queried), and the WiFi module still does what it does. As you say, I will have to do more checking. Argh!

Sent from Mail for Windows 10