EQ5 Pro control box not turning on

[Trevor-Austin]

I have what I was told was an EQ5 Mount upgraded to an EQ5 pro.

all been working great for several months. However tonight it powered on the handset then locked up, I powered it down and the handset won’t come back on.

the handset will power up from the USB cable, even firmware updated it just in case.

the control box is an MC002 Rev I 2010, but does have Synscan EQ5 written on it. 
no jumper on JP1 and no JP2.

I’ve tried 2 different power supplies and there’s 12v to the board and the on/off switch definitely works (checked continuity) 

is the board dead or the handset most likely? I’ve tried a straight through RJ45 patch cable so it isn’t the cable. 
I can’t test the control box independently as it doesn’t have a direct usb port only via the handset which won’t power. 
Any help greatly appreciated. 
 

edit: just got even stranger, if I power the control box on, nothing obvious happens. However if I then plug the USB cable in, it powers on and initialises and the Mount works perfectly.

 

Edited December 13, 2023 by Trevor-Austin

[malc-c]

Can you post up a picture of your synscan box.  If it's one of the newer type with a USB-B socket then it will have an internal  TTL serial to USB convertor enabling you to control the mount from a PC using EQMOD or GSS.  If this is the case then the synscan box is fully functional and the handset or the port where the handset plugs into is most likely the issue.

[Trevor-Austin]

It doesn’t have the usb, it’s a 2010 Rev 1 box. 
it has a handset port and a n auto guider port. 
but bizarrely works fine if I power the handset with usb it is fully functional from the handset and the control box runs the Mount for tracking and slewing from the handset or pc connected to the handset.

there must be a voltage converter chip blown in the e control box as it works 100% except for powering the handset. 

[malc-c]

In normal use the handset is powered from the power supply connected to the  synscan box via the four outer pins of the handset port.  Its internal logic runs at a lower voltage so this 12v is dropped via voltage regulation circuitry to provide 5v and 3.3v where needed.  When you connect the USB cable to the handset the 5v DC from the USB is used to provide the 5v and 3.3v lines, thus bypassing the 12v regulation side.  From what you have described I would agree that something, possibly the voltage regulator has failed which is why the handset is dead when the USB cable isn't present. 

Looking at images on the web, later handsets with USB ports have a daughter board containing all the ports.  I would guess that U3 that sits above the RJ45 connector is the culprit

 

 

It's daylight robbery that places are charging up to £127 for that small PCB !!

If you have a test meter you could always probe around to confirm the 12v is coming in to the board, and there are 5v and possibly 3.3v running to the main board in the handset (the 3.3v conversion may be on the main board rather than the daughter board)