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Post by unclebob on Jan 22, 2021 13:02:42 GMT
Today I gave the RAV4 a run to the postbox to post a medication letter , didn’t have the radio on to start with but the trip display was on. Posted letter and Re-started Rav and pressed radio on button...nothing, display blank yet cigarette lighter working (sure on the same fuse)..pressed eject on CD and disc came out, so power to the unit .
Pushed disc back in and it started to play but still no display, and not one control works on the main unit or steering wheel... so on a fixed volume....very odd !🤔🤔
Lucky for me I kept the radio/cd from the blue 3 door I had last, When I replaced it with the sat/nav unit ....any suggestions before I change The units over 👍🏻👍🏻
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Post by shcm on Jan 22, 2021 13:33:15 GMT
Kev had one repaired (not by me!) and the claim was faulty micro(controller). He'll probably chip in (did you see what I did there?), when it finally gets light up there in the arctic and wakes him up. Unit model number?
You could try pulling the power (permanent feed) and reapplying, but.........
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Post by unclebob on Jan 22, 2021 14:02:52 GMT
Yes saw what you done there 😉
Model number is 58812 and just found this nugget of information..what you think Andy ? ....
"I've now fixed two of these units and they both had identical problem and solution.
The problem was an intermitant fault, that after a random time, would result in a noticable snap and a failure of the sound system both radio and cd player.
Solution:- In both cases this is diy fixable with just some screwdrivers and a soldering iron.
First remove unit; this is done by unsnapping the two trims that house the face air vents this then exposes the fixing screws 2 at the rear 2 at the front, remove screws then theclimate control facia ,this allows the unit to come out far enough to unplug all connections both to the hazards ect and the radio unit.
Once out, remove the radio lid and the facia housing the controls, this just snaps out of retainers that you systematically release with a screwdriver. remove side supports marked L & R then this exposes a number of screws to remove including a small side panel that allows you to unplug the cd interface. Note ; it is not necassary to remove the cd player from facia plate. remove two screws exposed by removing control panel then remove ribbon from socket that supports lcd screen. This should then allow you to gently ease the radio unit clear of the facia plate and cd. Once clear remove all screws retaining back plate and pcb and lift pcb clear of case. Now viwed from the top and front you will see a heat sink that supports 4 big transisters , re-solder all legs of these transisters (3 legs each) this has cured the problem twice for me now. Assembly is reverse of reassembly plug in and check out those sounds,"
Do like to fix stuff so might give it a go when I get time .
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Post by shcm on Jan 22, 2021 15:14:57 GMT
Same model as Kev's one that died. What you've found there Bob, sound like a soldering problem with the main power amplifier transistors (them wot connect to the speakers) and I would think unlikely to result in no control over the radio (different circuit area). These head-units were a bit odd, in that Toyota's connection bus (avclan) between different units, did/does come out on connector pins on the head-unit and goes back into the head-unit on another set of pins. I'm sure they had their reasons for it (maybe to allow accommodation of the very old under-seat "black and white" satnav). If that "in/out", but external connection in the harness is not made, you can get some interest control side-effects, but, while the connectors are the weakest link, it seems a bit unlikely it's that. At this distance, I'm inclined to think you have Kev's problem (and I wouldn't wish that on anybody). Time to maybe swap the units. Off at a tangent, with respect to your "soldering fault" find: The unit is possibly too old to be subject subject to RoHS directive: en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive...and automotive electronics was granted a bit longer to comply too, but some manufacturers changed over early. The fault described with the PA transistors sound like just a dry solder joint (or cracked through hole joint). Yeah, that can happen with lead based solders, but RoHS caused a few reliability problems for a while. Initially the removal of the lead, had a tendency to: 1. Produce harder joints, more prone to failure 2. The lead free solder had a higher melting point, again leading to poorer joints if not careful with the soldering line process setup. 3. More tin "whiskers" appearing. 4. Other stuff Ironic, because the lead based solder was used to overcome the above. I did wonder at the point because: 1. The electronics is supposed to be recycled anyway (so you're not putting heavy metal back into the ground, although I suppose, in reality you may not really control where it ends up & who's "processing it", i.e. 3rd world country) 2. Like we never had several kg of lead in the vehicle anyway (think battery)! It's mostly been solved now, with a number of things. Of those surface mount components that have shown a tendency to crack (and a hard joint doesn't help), they now also have "flexi-terms". The termination material on the component is ever so slightly flexible. Some joys of high volume, low PPM reliability figure requirement, electronics manufacture! |
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Post by unclebob on Jan 22, 2021 16:11:55 GMT
Well I have nothing to loose to open it up and have a look...thanks for your input 👍🏻👍🏻
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Post by unclebob on Jan 23, 2021 11:05:47 GMT
Just read the hazardous bit about lead free solder...seems madness to shorten the reliability of a product, time to dig out my roll of 100% lead solder 😉
Life-cycle impact assessment of lead-free solder.
The United States Environmental Protection Agency (EPA) has published a life-cycle assessment (LCA) of the environmental impacts of lead-free and tin–lead solder, as used in electronic products.[16] For bar solders, when only lead-free solders were considered, the tin/copper alternative had the lowest (best) scores. For paste solders, bismuth/tin/silver had the lowest impact scores among the lead-free alternatives in every category except non-renewable resource consumption. For both paste and bar solders, all of the lead-free solder alternatives had a lower (better) LCA score in toxicity categories than tin/lead solder. This is primarily due to the toxicity of lead, and the amount of lead that leaches from printed wiring board assemblies, as determined by the leachability study conducted by the partnership. The study results are providing the industry with an objective analysis of the life-cycle environmental effects of leading candidate alternative lead-free solders, allowing industry to consider environmental concerns along with the traditionally evaluated parameters of cost and performance. This assessment is also allowing industry to redirect efforts toward products and processes that reduce solders' environmental footprint, including energy consumption, releases of toxic chemicals, and potential risks to human health and the environment. Another life-cycle assessment by IKP, University of Stuttgart, shows similar results to those of the EPA study.
Option C If soldering or fitting my spare unit fails, any recommendations on an aftermarket double din radio/cd,sat/nav,Appleplay unit 👍🏻
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Post by unclebob on Jan 23, 2021 16:38:37 GMT
Just been out to the RAV4 with a view to removing head unit ......it’s working again 🙄 which was sort of good as it was near on freezing outside 🥶
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Post by shcm on Jan 23, 2021 17:24:20 GMT
.....don't want to be a doom-monger, but, if you've not touched it, I have the feeling it will fail again.....unfortunately.
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Post by widge on Jan 23, 2021 17:40:46 GMT
.....don't want to be a doom-monger, but, if you've not touched it, I have the feeling it will fail again.....unfortunately. But at least it does indicate that it is basically fine, and hopfully just a quick bit of soldering if it fails again, thats if you can find the dry joint. |
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Post by unclebob on Jan 23, 2021 18:08:50 GMT
.....don't want to be a doom-monger, but, if you've not touched it, I have the feeling it will fail again.....unfortunately. Yes I take that on board. Retrieved the spare radio from the shed and took the top off out of Curiosity, spotted one of the 3 legged transistors that give trouble, this one looks all good...so it’s ready to fit if required 👍🏻  |
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Post by shcm on Jan 23, 2021 22:15:09 GMT
Yes I take that on board. Retrieved the spare radio from the shed and took the top off out of Curiosity, spotted one of the 3 legged transistors that give trouble, this one looks all good...so it’s ready to fit if required 👍🏻 Well have a good look. Duff solder joints can be difficult to spot. Microscope job often. I've opened a few head-units and I do wonder how they get away with some of the things. That transistor (looks like an insulated TO-22O package to me), even if it's not dissipating much & therefore doesn't require bolting to something for heat-sinking purposes, it should be attached to something a bit "solid". Like it is in the picture, it has the potential to vibrate (bit more mass on legs compared with other leaded components on there), which does have a high probability of leading to joint failure. OK, possibly there may be less vibration in-cab, but I'd have to wear "ribbon-of-shame" if I designed that into an under-bonnet ECU. I suppose the unit design went through the usual "bake, freeze & shake" cycles @ validation time and passed, but it doesn't look right....... It might be a trick of the picture, but the white ribbon looks like it might have some damage? |
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Post by unclebob on Jan 23, 2021 23:30:52 GMT
There are two transistors that need to be checked, the free standing one and this one attached to the casing , both a D1273. I’m sure the ribbon cable is ok.  |
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Post by shcm on Jan 24, 2021 0:14:52 GMT
Yeah, they are marketed as power transistors for amp output (speaker drive). It's very, very unlikely a problem there would result in a lack of control or no display. More likely no sound or intermittent sound.
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