Hand held exhaust analyser
Hand held exhaust analyser
(OP)
Hello everyone,
another headache,my portable 4 gas analyser has stopped working. The SMPSU that plugs into mains is supplying the 10vdc to the pcb,as I have checked the power lead,and I've checked the DC socket solder points on the board. But where do I check next? (The picture is large so it can be downloaded and view with Windows Viewer)
another headache,my portable 4 gas analyser has stopped working. The SMPSU that plugs into mains is supplying the 10vdc to the pcb,as I have checked the power lead,and I've checked the DC socket solder points on the board. But where do I check next? (The picture is large so it can be downloaded and view with Windows Viewer)





RE: Hand held exhaust analyser
Without a schematic, trouble-shooting can be very difficult. But it's perhaps worth examining the PCB under a microscope, especially around any components that are hot or mechanically strained, for cracked solder joints. But the odds are quite low you'll find anything that obvious.
RE: Hand held exhaust analyser
Unfortunately your supply check and perhaps some other voltage checks on the board are about the most a neophyte can do on these types of failures.
There is one more easy thing to check. Cast about the board a little trying to look up the data sheets on a few different integrated circuits you find there. Looking at the data sheet find their supply pins, be they plus or minus supplies and measure them carefully without shorting to nearby pins to see if they are what they should be. +5V, +7V, +10V, +12V, -5V, -10V, -12V, etc. This will show if an on-board regulator has taken a walk or not. If one has they are usually fairly easy to fix.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Hand held exhaust analyser
Other than that, with a schematic or a repair manual, it would be TOUGH.
TTFN
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RE: Hand held exhaust analyser
The cheek of it
I'll try your other tips later,need to get to work.
That has 470uf 35v on it. Just done some googling on how to test it with a DMM,using an EM129 on 20M ohm setting,it reads 5.56.
The analyser is an SPX which got bought out by Bosch. Quite possibly Bosch won't have anything to do with it,little chance for any repair manuals/schematics
Thanks again
RE: Hand held exhaust analyser
Caps are generally cheap, under a couple of bucks. I can only say that my ludicrously expensive to repair fridge was brought down by a cap that cost $2.35 at Fry's; it was going to cost $400 to send the board to someone in Kansas to replace that cap.
TTFN
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Of course I can. I can do anything. I can do absolutely anything. I'm an expert!
There is a homework forum hosted by engineering.com: http://www.engineering.com/AskForum/aff/32.aspx
RE: Hand held exhaust analyser
Those SMD aluminum caps can be a real pain in the butt to solder in or out.
Often, the pin voltage tests I described above would show anomalies if caps were a problem.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Hand held exhaust analyser
RE: Hand held exhaust analyser
RE: Hand held exhaust analyser