I was sent a Pentair Intellitouch Indoor Control panel from a gentleman who said the controller showed nothing on the display, made all kinds of noise, and got so hot that it browned the white plastic base. He was worried it was going to catch fire!
When I received the unit the first thing I did was a visual inspection. Nothing was immediately obvious so I connected it to my bench power supply and turned it on... upon power-up it beeped, screeched, and the on-board 5 volt regulator (U8 in the bottom right) got very hot. The preset 1/2 amp current limit kicked in almost immediately, making the voltage drop under 5 vdc so the board couldn't control the piezo speaker (hence all the beeping and screeching).
These units typically draw around 140-180mA (depending on your led/lcd brighness settings), but this one instantly cruised past the 500mA limit. The over-current condition was a clear indication that there was a short somewhere. A more thorough inspection was in order, and after removing the lcd the fault was obvious...
In the lower middle of the board you can clearly see a very charred capacitor, C23. It and the neighboring diode D3 and inductor L3 were smoked. The capacitor and diode had both "failed short" which basically means they created a short-circuit from power to ground... so the outdoor panel's comm port red/black wires (+15vdc) couldn't supply enough power to the indoor board which made it squeal like crazy. The inductor still conducted but it was slightly melted from the excess of current that had gone through it and I didn't trust it.
These blown components are part of a "boost" circuit that takes the 5 volts DC from regulator U8 and bumps it up to ~21 volts to drive the LCD (you can sort of see a light green shaded region surrounding parts C22, U4, U5, Q2, R20 etc, which makes up a ground plane for the boost circuit). No other components were damaged, and replacing the cap, diode and inductor fixed the problem. I'm still using it to this day!
People complain about how old and outdated Pentair technology is - and it is! - but it's also tried-and-true, pretty darned hardy equipment that can tolerate quite a bit of abuse. I was told this unit failed after a lightning storm, and not too much out there - no matter how hardy it is - is going to survive a lightning strike. Unfortunately, these damaged boards usually get tossed into the bin and replaced with another $$$$ unit, but they can often be repaired!
When I received the unit the first thing I did was a visual inspection. Nothing was immediately obvious so I connected it to my bench power supply and turned it on... upon power-up it beeped, screeched, and the on-board 5 volt regulator (U8 in the bottom right) got very hot. The preset 1/2 amp current limit kicked in almost immediately, making the voltage drop under 5 vdc so the board couldn't control the piezo speaker (hence all the beeping and screeching).
These units typically draw around 140-180mA (depending on your led/lcd brighness settings), but this one instantly cruised past the 500mA limit. The over-current condition was a clear indication that there was a short somewhere. A more thorough inspection was in order, and after removing the lcd the fault was obvious...
In the lower middle of the board you can clearly see a very charred capacitor, C23. It and the neighboring diode D3 and inductor L3 were smoked. The capacitor and diode had both "failed short" which basically means they created a short-circuit from power to ground... so the outdoor panel's comm port red/black wires (+15vdc) couldn't supply enough power to the indoor board which made it squeal like crazy. The inductor still conducted but it was slightly melted from the excess of current that had gone through it and I didn't trust it.
These blown components are part of a "boost" circuit that takes the 5 volts DC from regulator U8 and bumps it up to ~21 volts to drive the LCD (you can sort of see a light green shaded region surrounding parts C22, U4, U5, Q2, R20 etc, which makes up a ground plane for the boost circuit). No other components were damaged, and replacing the cap, diode and inductor fixed the problem. I'm still using it to this day!
People complain about how old and outdated Pentair technology is - and it is! - but it's also tried-and-true, pretty darned hardy equipment that can tolerate quite a bit of abuse. I was told this unit failed after a lightning storm, and not too much out there - no matter how hardy it is - is going to survive a lightning strike. Unfortunately, these damaged boards usually get tossed into the bin and replaced with another $$$$ unit, but they can often be repaired!
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