Author Topic: problem with mcp3208 chip  (Read 7746 times)

Offline gunni

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problem with mcp3208 chip
« on: November 30, 2008, 06:19:39 pm »
Yesterday I was unaware that there where pullup´s for the analog channels so I wired in a variable resistor the gave off 0-5 from low to high. Connected to channel7 and was able to view the voltages
on the Fuel Pressure gauge.
as this was the adjustment channel for boost control duty cycle the duty cycle adjusted as well.

Today I was going to add channel 5 and 6 in the same manor but that did not work at all.
And there aren´t any voltage gauges for those either.

I accidentally scraped one wire , which one I don´t know but it was one of the channels to 12v on my little test bench.
And there was some smoke from the board, I wasn´t able to see where from but nothing seem destroyed, but now
channel7 shows 5v always no matter how the wiring is done and even If I wire up the potentiometer as before and can actually read 0-5v on the INPUT PIN to the chip software doesn´t register anything and duty cycle doesn´t move.

I´ve search the wiki but haven´t found a way to diagnose the chip any further. But since ch7 now shows 5v no matter what I´m sure there is something wrong.

Ch5 measured 2,08v
Ch6 measured 2,15v
Ch7 measured 5,08v

Added.
In this picture there is a place for resistors for the pullup, from the 5v source they measure 5v fine
but after one reads same as channel 6 and the other ch7. Resistance is supposed to be 2,7kOhm, but channel 7 shows that but channel 6 shows 600ohm. I removed the soldered resistor and measured it to be 2,7k ,

For channel 5 to work isn´t there internal wiring required as well?
« Last Edit: November 30, 2008, 06:25:40 pm by gunni »

Offline Sprocket

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Re: problem with mcp3208 chip
« Reply #1 on: November 30, 2008, 06:50:16 pm »
Smoke is bad, hence the term, smoked, usualy terminal for components :-\

I believe the MCP3208 chip doesnt like 12v, as you would expect considering its input is 5v

I smoked the P259 chip the other day ;D

Offline gunni

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Re: problem with mcp3208 chip
« Reply #2 on: February 07, 2009, 06:04:27 am »
Ok, I finally got around to replacing the MCP chip.

That worked out fine, not easy to de solder these types of chips.
Dremel helped a little bit  :P

Anyway, I was having battery problems that where driving me up the wall.
So I only just managed to reload the firmware. Turns out it was the battery and charging equipment that was messing with the serial connection.

I wasn´t able to check out the repair, but the TPS, Coolant and Intake air all had problems after I destroyed the chip.
I was just able to check them and they all behaved as desired.
I´ll be able to check out the rest tomorrow and continue with what I was doing, which I can´t really remember anymore
it´s been so long  ???

Offline Denmark

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Re: problem with mcp3208 chip
« Reply #3 on: May 27, 2017, 12:46:30 pm »
Were is the mcp3208 chip on the board , i Think mine is dead also
I have No egt anymore , changed the sensor as i thourgh that was broken
But it still just ready 0c in

Picture with pointer would be great 😉

Thanks
working on the boxer