No Power in Watlow 988 Series Temperature Controller (Epoxy To Fix Broken Track)
One of my customers brought in this Temperature and told me that is just stopped working and he need it urgently and he can’t afford to buy a new controller. I told him that I will try to repair it but there are no guaranties.
First thing I did was to power the unit up via my Isolation transformer and a light bulb. Sometime people may bring in equipment and there is nothing wrong with it and fault lie somewhere else. But in this case the unit was as the customer said No Power.
Then I open the unit for inspection…. I check on the power supply section and surrounding components and found a 10uf-35V tantalum capacitor and a 10 uf 35V electrolytic capacitor bad. See picture below:
The Electrolytic Capacitor next to the tantalum had leaked it electrolyte and shorted the Tantalum cap. I then remove the both Capacitor and notice that the leaking had also taken out the circuit trace for the tantalum Cap. I clean all the carbon from the trace. See picture below:
I decided to make a new trace using copper foil and conformal coating epoxy to glue the trace back to the circuit board to make it look original.
First I laid down some epoxy and the place the trace on the epoxy and using tape to hold it in place while it dries.
I let the epoxy dried for 24 hours and then I soldered the two pads together. I then install a through hole tantalum cap and then the Electrolytic cap and apply some more Epoxy over the solder pads.
I the assembled the unit back together and tested the unit to its full functions. I used my Transmation thermocouple calibrator for the input test and it worked perfectly. Left the unit running for 4 hours and it was working as it should. Job completed. I call the customer and he was delighted to hear the good news.
This article was prepared for you by Andre Gopee from Calitech Limited Trinidad West Indies.
Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.
By the way if you have any good repair article that you want me to publish in this blog please do contact me HERE.
Note: Please check out his previous repair article below: