Dolphin Diagnostic stops after seconds. Fixed . Replaced Bad Relays

by Vittorio
(Italy)

Hi All
My 5 year old Dolphin Diagnostic was not working; when powered it was running in one direction only for few seconds and after it stop.
I have seen that it seems a quite common issue, so maybe this analysis can help someone.
In my case it was the relays placed on the board that was not working in the proper way. The coil was good and from outside you can hear the “click” of the relay, but one of the contacts was always open.
This component is used for changing the motor running direction, so the Dolphin goes forward and backward.
I changed the relays with a new one and now the Dolphin works fine again.
It is a very common, few euro component: 5V coil, DPDT, 5A contacts. ( In any case I replaced it with a 8 A contacts ).
The contacts of the not working relay, are very bad, black and full of craters. Maybe this component is under – dimensioned and after some working time it fails.
If you also have to change it, pay attention on the de-soldering phase of the bad relay; you need some skill as it is assembled on a 4 layers board and you have to absorb all the solder before to de-attach the relays pins.
I hope this can be useful.
V.