combination meter repair - DIY

I can atest to Step 2) *working*. The cluster displayed fully on action #3 "turn on lights". The FOB was inserted in the slot. The display turned off normally also... Thank you!

 

Yes; but make sure it's 105C - not the cheap stuff. You may end up doing the job again after a few summers, if you use the lower heat rated cap.
Whenever I repair power supplies; I always replace with slightly higher voltage and temperature caps that will fit the slot. I've never gotten repeated circuit failures - going on 20+ years. Whereas the OEM circuit failed around 7-8 years in.

 

Nichicons are not the cheap stuff, rubycons are very good also.

 

Have a problem after just doing this with 220uF 16V capacitor.

Now fuel level indicator (the whole indicator section with level and the E and F icons ) and the “mi” after ODO numbers are flashing. I removed the old capacitor before installing the new 220uF.

Ideas on what might be causing this and what to look at?

Thanks

 

Did you reconnect the plugs that go in the side. Check also the other end of those cables, sometimes they get inadvertently disconnect at the other end.

 

Also look for solder splashes and signs of adjacent components that may have gotten overheated; burnt traces.

 

Check your work. Make sure nothing has been damaged while you were in there. I've never heard this before.

 

We just replaced all three of the capacitors on the combo meter board. After reconnecting it, we found that the problem with the dashboard was NOT fixed. Also, now we're seeing the icon for "hybrid system malfunction" in the center display. Any suggestions?

 

Winner winner chicken dinner!.... So it turns out that the 4-wire connector that goes in the side was "installed" but not FULLY pressed in. The extra 1mm made the difference.

 

I’ve been putting up with a bad combination meter for about a year now and recently I found a really good deal on a used combination meter from a 2006 Prius at the local junk yard so I bought it.

After I opened it up I noticed that the 100 uF capacitor that everyone says goes bad says 220C on this one.

Could this be a combination meter that someone had replaced under recall? And if it is do I still need to replace the capacitors?

I’ve also enclosed a picture so you can see it better. Thanks!

 

Not a capacitor wiz but That one looks bigger in physical size than the one I replaced so likely the upgraded version. Now that you know what it takes to take out the display (if you got the display from a UPull) and your self-assesed soldering skills - Do you want to roll the dice that it will work or do you want to put in a capacitor you are sure will work?

Me, I'd install this new one as-is... And I fixed two in two Priuss already.

The risk with pre-fixing it is a) it may not need it b) if you did it and it doesn't work you will always be thinking - did I break it trying to pre-fixing it c) as you know now taking the dash out is not a super big deal.

You can pre-test it by putting the new one in and assembling the dash just enough to test it and if it works, put the rest of the dash back (trim/center console/glove boxes etc)

Pre-testing is a good idea - like I'm my case above one connector wasn't ALL the way in causing the gas gauge to not work. I was glad I didn't have to take off those extra parts.

If the pre-test fails you can choose to repair yours since it's already out or the new one.

In any case, having the right $1 capacitor in hand might be a good idea especially if your location doesn't have a local electronics supplier and you'd have to wait to get one delivered.

I'm guessing since you put up with it for a year and got a replacement instead of soldering yours, you are not comfortable with the soldering part so maybe you want to put the new one in first and see how it goes.

Let us know what you end up doing and how it turns out.

And if you want bonus points - once yours is fixed - offer on here the second one and the extra capacitors (since you're likely to be buying at least 5 if you order on line) for the price of postage so someone in your situation can pre-fix yours, have one to swap, and can offer-forward their spare.... And if turns out you have to fix your new one you'll see how easy it is to replace that capacitor so you may just fix the second one too and offer someone a fixed display :-p

 

If you are going to go through trouble of disassembling the dash to get to the combo meter, then just fix your present one. First of all, you will keep the mileage reading, whereas the other combo meter you bought will display the mileage of the car it cam from. Second, it is super easy to replace the cap. You do not have to replace it with a surface mount component. I replaced mine with a through-hole 220uF cap I scavenged from a pile of old electronic parts I keep around (I'm a geek and a life-long electronics enthusiast). If it makes you feel better you can buy a new one, they are about $0.20 or something. Sticking an unknown combo meter in your car creates a possibility for having to go in again for the same problem. Though, I do see your point about the cap being 220uF already and may have been replaced previously. It may have, but who cares? It's still good to have a known good part in the combo meter and I would say I would want my original meter with my car's mileage in there. But if you feel better installing the one you bought, nothing wrong with that either. Do what you are comfortable with. All I am saying is that getting to the combo meter is 95% of the job. Once you've done that, the choice is yours as to how to proceed. I have posted pictures earlier in this thread (December 2019) of my repair with a through hole 220uF cap. It's not pretty, but it is still rocking after several years.

Good luck and be careful with those air vents. They break easily.

 

Do you have a ballpark for how long that 220µF cap had been sitting there in your pile, and did you do anything in particular to reform it before putting it to use?

 

I should have explained that my Prius is a 2005 model with almost 224,000 miles on it. I am putting miles on the car so fast lately that it probably won’t be long before I’m dealing with the “Odometer stuck at 299,999 miles” problem. I planned to buy an upgraded combo meter from Matt at Texas Hybrids but some situations came up and money is very tight right now. I was looking on car-part.com and found a used 2006 combo meter for $60 locally. After reading on Priuschat I see that I can install a newer combo meter into my car and avoid the 299,999 problem. I believe the light cluster also must be switched. I have both of these parts from the salvage yard. I will never be selling the car so the mileage on the odometer doesn’t concern me.

I’m leaning towards just installing the new meter and hoping for the best. My soldering skills are not the greatest. I will make sure to test it before I put the dash back together completely. Thanks for all the replies and suggestions.

 

Given how much time it takes to access the circuit board, and how cheap a good capacitor is, this isn't a situation where saving $0.50 (ballpark) on a new cap makes a lot of sense. When buying capacitors at Digikey (for instance) there is a "lifetime" column which can be selected as a filter. It is in hours at a given temperature. Pick a replacement capacitor with a high value there. Caps have lifetime ratings for temps like 105C or 125C, way above what they might see in a car. A cap which will last 10K hours at 105C should last much longer than that at 60-70C, which is about as hot as it usually gets in a car. Unless the cap is going to space, high altitudes, or the South Pole don't worry too much about the lower end of the operating temperature range. It is usually -40C or -50C, and most vehicles will never see that. Of course the replacement cap does need to fit into the space available, and that is likely to be more difficult constraint to match than the estimated lifetime value.

The caps in the picture look like they are "Conductive Polymer Aluminum Solid Capacitors" (because colored segment on top of solid can, rather than a set of intersecting lines in a thin foil cap). That type of capacitor lasts a very long time. See for instance:

-- GIGABYTE --Geeks Column of the Week - All Solid Capacitor

Note the lifetimes in the table Average Lifespan of Solid Caps. vs. Electrolytic Caps. Keep in mind that the table is for a capacitor running well within its specs. The problem with this board was that Toyota used one running on the hairy edge of the correct value. I think the problem is that as these aged their capacity dropped a little (made up numbers, I don't recall the actual uF) from 100 to 80, which because of the tight tolerance, was too much. It isn't that they failed outright. Using a 220 uF if it drops to 200 uF with age it will still work fine, as it is way above the minimum spec. Remember that most small caps are only accurate to 20% even when new.

 

I have no clue how long the cap was in my possession and I did no "reforming", but I am not exactly sure what you mean by that. If you mean reform the leads, I did do so to make it fit the situation on the combo meter board, but that's just bending some tiny wires to shape. I looked back in this thread to find my post and it was in December of 2019. So two and a half years now and no issues. There is no need to overthink this. This is not a part of electronics that is super precise. A good quality electrolytic cap that is a larger than 100uF is all that is necessary.

 

Sounds great. I think you should be good to go. It definitely looks like a replacement cap in there because original was 100uF and yours is 220uF. That is a good thing! Best of luck on the replacement, it should really be fine and you will have an odometer that is not limited to 299,999 miles.

 

The blue words in my question were the link, for anyone unsure of the process to reform an aluminum electrolytic cap that has been sitting unused.

The aluminum oxide layer that makes an electrolytic cap work is kept intact by regular use of the cap. This is why electrolytics have polarity, and why they have shelf lives. The layer slowly dissolves in a cap that sits unused a long time.

If a cap was shelved for a long time but not otherwise damaged, the layer can be electrically reformed, following procedures you can read about with that link, and then the cap should be good as new. But it will not always go well to just solder it into your circuit and plug in the power and hope for the best.

 

I hear what you are saying, but I wonder what "sitting for a long time" means in this case. A year? Ten years? Hundred years? I have never bothered about that when salvaging caps for circuits such as the one in the combination meter in question. If I were re-capping a piece of equipment where these caps were in, say, a signal path of an audio amplifier, I would never use a salvaged cap in the first place. As for this type of repair, I am personally comfortable using a cap that has been kicking around in my pile of PCBs. If was not comfortable, I would just buy a new one, they are very inexpensive. It was more a question of convenience for me. I have a pile of old electronics for salvaging and certain applications, such as the combo meter repair are perfect candidates for a salvaged cap. I have been running that in my combo meter for the past two and a half years and so far so good. If it fails again, I'll fix it again, it's just not that big a deal for ME. Others should definitely do what is comfortable for them. A new cap is probably the best way to go for most folks as they are cheap and easy to source. I have been playing with electronics for nearly 50 years now and am very comfortable with determining what will (most likely) work and what is iffy. I am certain I measured the cap with my meter before sticking it in, so it wasn't just put it in and hope for the best. I also powered it up to test before finalizing the job, so if it didn't work, I would have used another one. I have more than plenty. I am not sure it is worth investing any time into a $0.35 part such as for reforming or whatnot. If it's good, use it, if not, throw it away and go on with life. That is my process and that is probably why I am not even aware of the reforming of electrolytic caps.

 

Something like more than five and not a lot more than twenty, depending on storage conditions 'n stuff, is the gist of what I'm reading. Some manufacturers publish lower numbers, but are probably being conservative.

My purpose wasn't really to pick on what you did, but to get the info on reforming into the thread. It's not very much work to do, and doesn't require any materials that aren't probably already in the same junk drawer where the old caps are, so there's not much cost to doing it, if an old cap's about to go into a circuit.

Without reforming as a separate step, all that may happen is that the circuit you put it into ends up reforming the cap when first powered up. The cap will draw an increased leakage current and the circuit will supply that for a while, warming things up, until the oxide layer is reformed and the current drops back down to spec. As long as the circuit can handle doing that and the cap doesn't overheat, it may be pretty uneventful. A separate reforming step in advance saves having to guess what the circuit can handle.