Of course the first step to any repair is figuring out what the heck is wrong!!
I'll poke around with it once my new goodies arrive. I'd rather have a somewhat working probe until then.
Yeah, that is not always easy to find the cause of cable assembly failures. It's best to start with the simplest, most obvious checks as a troubleshooting method. So, are you ready for this? I'll walk you through what I would do, based on my previous experience with a barrage of different types of gear and problems.
Start by gently cleaning the cable assembly of residual smoke, food residue/grease, etc, with warm, soapy water (without wetting the cable pass-through areas at the plug and probe, of course)...you need to see the cable to find the obvious signs of damage, as that's the easiest to search for and these are tell-tale signs of like failures. Pat off all water, or air dry. Carefully inspect the cable length for kinks or tight twists, cuts or any other obvious signs of possible internal damage caused by mechanical forces (such as from cooker doors or lids closed on cable). Note any suspect areas...you may mark them with a permanent marker for easier location/identification later. Plug the cable into the device, power up and start to slowly work from one end to other, gently twist and bend the cable in all directions (not too tight on bends) while observing the device for changes in readings on the display. If you observe a change in readings, work that area of the cable a little more vigorously to verify the exact location. Mark on both ends of the suspected area of cable damage...this is likely a failed area...there may be more than one. DO NOT bend near the probe or plug unless you find that nothing changes while inspecting the cable length...you may cause undue damage, as these are areas where strain reliefs are typically used to prevent kinks and bends (mechanical damage).
If the above method fails to reveal the location of the fault, dig out your analog or digital meter and test resistance of each conductor while doing the same as previously described...if resistance checks indicate no open circuits (has resistance) it is likely that you have a damaged receptacle on the device or a failed sensor....more on that shortly. If no open circuit is indicated, apply heat to the probe while testing for resistance. If the resistance does not change, your probe sensor is likely the faulty component, but no guarantees on that...pretty much a screwed unit at that point, unless you're REALLY handy (and patient) and can locate a component parts source for a new sensor that matches the resistance range and temperature range of your original temp sensor. This requires you to know all of that info before you try to order a new sensor, and this info is probably not readable even with a magnifying glass on the device, if it's even printed on it. A part number may be all you might find...then it's a game of finding the component manufacturer and finding the specs to determine what replacement component will be suitable if the original cannot be purchased. Resistance with temp sensors is vital to calibration measurements remaining the same as the OEM component. Did I mention that accuracy will become an issue? OK, now I did. Sensors packaged with a device are a close match to the device, and any changes can alter the calibration. Resistance specs on these devices are measure in fractions of an ohm, and if measured to infinite limits, none are identical...well, better said, good luck finding 2 identical components. A lot of hoops to jump through, and only your level of desperation will determine whether or not it is worth your time and effort once you reach this phase. Not to mention, due to the method of assembling the sensor probes, I doubt any of us back-yarders could even make the repair, even if it were possible, as it would be a delicate and time-consuming process using specialized tools. Add to that, most of these components are not available in low quantity orders, unless you're really lucky to find it at
digikey or some other electronics component vendor.
OK, last chance test, if the probe cable does pass testing for resistance and you have no other identical probe to test the head-unit with for functionality: CAREFULLY test for voltage output at the receptacle on your device. Be aware that one slip of a test probe could short circuit your device and possibly cause permanent damage. If there is not a seal on the case that would indicate a voided warranty (if applicable), you would be least likely to cause electronics damage by opening the case and locating the receptacle for further inspection (look for mechanical damage first) and testing. If you're really lucky, there is an internal fuse that can be de-soldered or simply snapped out of it's holder. Some devices may have built-in, automatic electronic protection, but only the really goods ones will have that...this is probably not incorporated into a device such as these, though. That said, use extreme caution and only do these types of tests without any interruptions, or more importantly, distractions.
So, if you find that there is no voltage at the cable receptacle on the device, you obviously have some more serious issues requiring in-depth inspection and testing. If you wish to further pursue in-house repairs from this point, drop me a line and we'll discuss some possible routes accomplishing it, based on your available tools and skill-set. Here again, with a few close-up photos so I see what you're seeing, it can be done, up to the point where you'll eventually exhaust your resources and need more specialized tools, materials, etc.
I only explained the problem with finding replacement component parts such as the actual sensor (plugs are easier to find and have less restrictive specs) for the event that someone might actually consider doing that level of repair. I personally would not replace some of these smaller components, unless I was looking at a $75-$100 probe assembly...'cuz you may need a few weeks of free time to do your research, not to mention waiting for an order, then performing the actual deed, and doing it right the first time (not destroying your new parts or the device as a whole)...to those who try it, my hat is off to you, 'cuz you got what it takes to fix pretty much anything electronic...best of luck to you.
So, I guess I dove deep into my past to find all this off the top of head, but it all applies to the temp probes we're speaking of. Yeah, I used to do a lot of troubleshooting back in the day...draw on me for more tips/info if you feel the need.
Hope this gives you enough insight to get started. The actual troubleshooting isn't that complex or difficult, but as you can imagine, the deeper the problem, the deeper the toolbox (and patience), and slower the clock needs to be.
Eric
Not to derail this thread: please use the PMs for further discussion, or start a new thread. Continue on with the thread topic.
Sorry about that DB...should have sent you a PM, instead.
DISCLAIMER: this only a representative sample of steps and methods based on my memory of 8+ years of self-taught industrial electronics repairs, and is not a complete guide, nor does it include EVERYTHING you need to know to complete the repairs of a faulty temp probe or head-unit. Travel this path at your own risk.
(stated for those who should not attempt these procedures due to the complete lack of necessary tools and skills, until seeking further consultation, developing the necessary skills and acquiring the necessary tools)
