HFS-3 thres problem ::repaired::

[SonOfAnarchy ZA]

Hi all I have a Aquamist system with a HFS-3 controller and its recently broke. When I turn the ignition on immediately the thres light goes on and if I go check the FAV it begins to pulse softly if I turn the car on it then pulses much "harder" even at idle doesn't matter how I adjust the thres pot. These are the following test point values when car is off and just ignition is switched on.

Test point 5 +13.8V
Test point 8 +13.3V
Test point 23 +13.8V
Test point 16 +0.61V
Test point 15 +4.97V
Test point 11 +9.07V
Test point 30 +0.81V

Anyone have any idea what the issue may be?

[SonOfAnarchy ZA]

Anyone??

[Richard L]

Can you check test point 20 for me?

[SonOfAnarchy ZA]

Ok my controller is at work will measure on Monday thanks

[SonOfAnarchy ZA]

Hi Richard point 20 measures 1.4v

[Richard L]

This looks normal.
One more measurement, pin 17.

Can you take a hi-res picture of the circuit board, top and bottom. I would like to spot any obvious problems.

[SonOfAnarchy ZA]

Ok so pin 17 has no voltage what so ever. The board blew on two spots as clearly show on the picture. The 310 resistor was completely burnt I replaced it with a 470 though maybe that was the issue but after getting the correct resistor there was not change in the controllers behavior. Thought maybe it was the IC that it goes to so I replaced that as well (will not give the part number over the open forum will PM you the part number I used if you need) and still have absolutely no change in the controllers behavior. The other place it burn is where you change between a positive and negative pwm input I made sure that there where no tracks off(the positive pwm track is off didn't bother repairing it as nothing will be going to that track). Please excuse the red and black cables soldered to the board its just so I can test it on my workbench. The Aquamist system is connected to my nissan 200sx running a haltech ecu with a negative signal going to the controller. Appreciate the help thus far.

[SonOfAnarchy ZA]

Originally Posted by Richard L

This looks normal.
One more measurement, pin 17.

Can you take a hi-res picture of the circuit board, top and bottom. I would like to spot any obvious problems.

And there is the top.

[Richard L]

The resistor you replace should be a 1M ohm not 470 (47ohm). Try the correct resistor value and retest.

[SonOfAnarchy ZA]

I was working off this picture for the resistor value but i just put a 1M in and its working like a dream THANK YOU very much for your assistance!!!