ALTEC-410 Temperature Controller Burned parts

hi,

I have accidentally pluged my controller in the wrong direction. I need to identify burned parts on the board inorder to repair. Upon inspection there are 2 burned resistors and 1 transistor please see attached photo with the red circle.

thank you

Hello!

Component values are as follows.


A -> Resistor 8,2kΩ/1%, package 0805
B -> Resistor 5,1kΩ/5%, package 0805
C -> P-channel J-FET (junction) transistor PMBFJ177 Datasheet at the attachment.

The chip marked with an arrow is very likely also damaged.
Check the diode marked with a square.
Also measure the resistance on electrolytic capacitor marked with a square.

Hi,

I have replaces the parts with through hole parts as I can't source them locally. Its still sounding an ALarm when powered on. It can't seem to read temperature. I have checked the capacitor and the diode and it seemsed to be good

Replace that yellow capacitor too (100nF/100V), it looks like its plastic casing is melted. What about this 16-pin IC? Have you replaced it as well? Please attach the close-up photo of both axial resistors.

Hi have replace the 16 pin 4051 ic. The yellow capacitor is good. I have checked using multimeter I hit it several time with my iron while changing the 16 pin I.c. After replacing the jfet. I am able to start the program unlike before. But problem is seems like. It cannot read temperature. I'm starting to wonder if the stc90c58 is damaged.

Replace all three 8-pin chips located near the yellow capacitor. At least one of them is almost certainly damaged.

Hi sir, I have replaced the 3 ic and the controller is showing temp readings. Problem is the reading are in 3 digits EG. 363, instead of the usual 2 digit reading upon start up. I checked the resistor near the 3 ic. One was off 7503 resistor should be 750k, I removed the ic and it was reading M-ohm I wonder if this is the problem. Also I wonder if this resistor is 1% or 5 %?



I checked resistors and capacitors and found one capacitor that seemed off. I was wondering if you know the value for this capacitor


This capacitor has no resistance and no capacitance reading. I wonder if this maybe the cause of the problem.

Hi sir. This is the outcome of the the parts that I replaced. Please see photo

What if you try to measure 100°C boiling water temperature? Does your controller read 1000?

Hi, sorry for the late reply. I have tested the controller on a soldering iron the stand alone temp monitor is reading 100 the altec 410 would show 400 so, it is not giving an accurate reading. I would also, like to ask if if this could be caused by the parts that. I replaced. The smd resistor I replaced with axial resistors and the transistor. The 3 ic I replaced we replacement parts. I couldnt find any originals. Would this cause this problem?

Please, sink the thermocouple into a boiling water as colleague Vogelek23 suggested in post #9. What temperature reading do you get in this case?