HEQ5 motor control board

[malc-c]

Hi guys,

Seems my HEQ5 has died.  I'm getting power to the mount, power from the socket to the yellow cable that connects to the motor board, but no indication from the LED and no connection with the PC, plus the steppers don't sing at all - it's dead !

No sign of any blown components, but the board does seem to have  what looks like varnish or something over the two driver chips on the left, which makes me wonder if the large (presume capacitor) component to the left has leaked

Anyone have any ideas on the cost of a replacement set of boards ?

[oldpink]

the varnish will be to protect the chips from Dew not from a leaking Cap

[Cornelius Varley]

A new MCB will cost you about £100.

[malc-c]

cheers guys

[malc-c]

After further testing without success I bit the bullet and ordered a replacement mainboard from OVL.  Excellent service as the board arrived the next working day, so I set about plugging everything together and then powered up the boards..... the LED failed to light and i thought that it must be something to do with the smaller power board, but I thought I would try and see if EQMOD would connect anyway, and it did.  So everything was working apart from the LED, which when tested with a DVM still illuminated.

Before I placed the new board in the mount and put the motors back etc I thought I would try the old board one more time... so everything was disconnected from the new board and hooked up to the old... and the sodding thing worked !

So now I've spent almost £100 that I didn't need to, which being un-employed was quite hard to find.  Why the old board failed to work, and then start working all of a sudden after connecting a new one I have no idea...

Anyway the new board has been fitted and the mount re-assembled.  Comms between the PC and mount tested and the scope slews just fine.  I'm not sure what to do with the old board, might place it for sale in the classified, or keep it as a spare, but as it has been in the mount for several years it could be a while before it gets used again given the lifespan !

[hazegood]

sounds like a dry solder joint somewhere on the old board, disconnecting things and reconnecting them may have knocked it back in to place enough for it to work

[oldpink]

check the solder joints on the power input pins
on laptops these often work loose with the inserting & removing or general wiggling of the power adapter