combination meter repair - DIY

Good point. I am so used to replacing caps in other applications after they have vented that I forgot that in this case the problem comes from just losing a bit of capacity. Not really failed, just aged a bit. That said, I think I would still replace it rather than piggybacking another cap onto it. In part because it may have lost capacity because it is drying out and could go on to outright failure, but mostly for mechanical reasons. A cap that is properly seated on the circuit board with its leads soldered into through holes will not vibrate much, whereas one tacked on elsewhere will exert more force on its leads as the car moves. That will stress the solder joints so that they are more likely to crack eventually.

(An interesting read concerning how to solder for reliable connections (for a much more extreme environment) is the NASA standard for "Soldered Electrical Connections". There is a copy here:

https://nepp.nasa.gov/docuploads/06AA01BA-FC7E-4094-AE829CE371A7B05D/NASA-STD-8739.3.pdf

As you might well imagine, dangling components are not allowed in spacecraft electronics!)

What about the other capacitors on the board? If this one is losing capacity, probably the others are doing so as well. This one seems to be involved in a critical timing circuit whereas most of the others are probably just there to filter noise out of the DC power. That is a much less demanding task. It may be that somebody has seen issues when these other caps go but I have not yet encountered that thread.

Edit: checked earlier in the thread, this seems to be a surface mounted cap. Those are harder to replace with just a soldering iron than through hole mounts, so that's probably why the piggy back approach was used. Harder, but not impossible, for instance:

 

I think you are correct in saying that only C3 seems to be critical in the value as it's part of a timing circuit (reset/power-up?) rather than a simple filter. Most caps are +/-20% on value and if the new part started with -20% and aged just enough, its value may fall below what works and we have a problem. I think an old cap needs to be removed, for sure. There is no good reason to leave it in there. None whatsoever. I did not use the vias and just soldered my non-SM cap to the SM pads. I am confident enough in my soldering skills to have done that. If it works itself loose, I 'll go back and redo the job using a more secure method. I think it will last, though. I chose not to replace any other components. I really do not think it's necessary or a good idea. The board looks very well made and I do not want to introduce any variables of re-work into it. No matter how good a re-work is, it's a re-work and will never be as good as Toyota factory. I just did the absolute minimum to get the problem resolved. I highly recommend others do the same. the minimum DOES include removing the old cap, however.

 

Edit: checked earlier in the thread, this seems to be a surface mounted cap. Those are harder to replace with just a soldering iron than through hole mounts, so that's probably why the piggy back approach was used. Harder, but not impossible, for instance:

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Nice video. But my skill level is not that high. I have pulled the pads off of PC boards in the past when removing surface mount parts, and if that happens might end up tossing the board. If you don't have a high quality microscope to inspect work done then the less changes the better.

In addition there were vias that could be soldered to so a thru hole type cap should grip pretty well. Time shall tell.

 

25 x 220uF 16V 105C Radial Electrolytic Capacitor 6x11mm - USA SELLER FREE SHIP | eBay


I bought these and did this repair the other day. I twisted the surface mount off with needle nose pliers and left the wire on the replacement caps long. You could do this job with your toes. The pads are not near anything else. Just flick the surface mount legs off the pad and bend the wire on the new and heat it up. As long as you use an electronic soldering iron and not a stained glass soldering iron you will be fine. Its the easiest job I have done in a while and it took 5 minutes to remove cap and replace. I have another car to do I will include pictures on the next one.

 

I just did this fix as well on our 2007. Use this Youtube vid for the display board removal and reinstall.

Used these two vids for the soldering job.

Worked like a charm! The most difficult part for me was putting the whole reassembled dash top back in. Awkward to hold and center by myself and make sure the tabs at the very back edge engaged under the windshield. Otherwise straight forward and somewhat time consuming (3 hours or so). Saved about $75-$1200 going by what online posters said.

 

I just completed this on my 08, took a few hours to remove and install.

 

Okay, so I did a DIY repair last year after a month of getting my 07 (around March), and the instrument cluster worked great.
Until it started acting up around September. And from there, even after changing it to a 20uf capacitor, the cluster started working intermittently, with it becoming increasingly frequent as time goes on.
What gives!?
I’m not about to take apart my dash again.

 

Should be 220 uF.

 

I promised to post a picture of my next cluster repair. I also made the comment that you could solder it with your toes. Well sorry but my picture is not the greatest. It looked better when I was viewing it through the camera. But this time I took the laziest path I could cause I know anyone could do this job. I twisted off the cap and the little legs were still on the pads. I went to heat the legs up to flick the legs of the smt and just said forget it. I dropped a dot of solder on top of the surface mount legs and touched the replacement cap legs on the dot of solder and called it good. Installed the dash and it works just fine. If in fact, the bigger the blob the better the job, then I did a really good job

I used another cap out of the bag I bought from here 25 x 220uF 16V 105C Radial Electrolytic Capacitor 6x11mm - USA SELLER FREE SHIP | eBay

I must admit I wish I had used Windex on it before I put it back together. I wiped it clean and it looked ok but it could look cleaner now that its dark and the display is working. Oh well what can I say.

 

First the good news - that repair will probably last the life of the car.

Now the bad news.

You used no name capacitors. Terrible idea. Those may not have a low ESR, might not be anywhere near their specified capacitance, and have who knows what electrolyte in them. The wrong electrolyte can cause this type of capacitor to swell, leak, or even burst. Fake caps are a real thing - avoid them like the plague. This link discusses some reputable sources for these components - personally I always use Panasonic FC or FM from Digikey (usually, sometimes Mouser) when repairing electronics:

Capacitor Lab - Where to buy Low ESR Capacitors for Motherboard and PSU

The description of the soldering technique is worrisome too. All the solder must melt and it must wick up onto the metal surfaces properly. Otherwise one can have a cold solder joint or various other problems. These can crack which usually leads to intermittent or total failure of the connection. If it looks like a blob on a blob it wasn't soldered right.

 

after your first good news there is no more information of value. Nobody needs their repair to last longer than the life of the car, right? I'm trying to get people to fix their own stuff when its easy, and this is easy. I spent 20 years in the semiconductor industry as a equipment tech so I know how to solder. But I want to say you don't have to be mr solder to not send your stuff off to get it fixed. I will update the world when any of these caps fail, which they wont.

 

I questioned the capacitors because they are really, really, really cheap. $3.49 for 25 pieces is 14 cents each. The brand listed is "AEC" which is not a manufacturer that I have ever heard of. That is almost certainly part of the product description: Aluminum Electrolytic Capacitor. Look up 220 uF caps on digikey rated at 100-120V and they start at 24 cents each in bulk (hundreds to thousands of pieces minimum order). The lowest price in their list for caps which can be purchased in that small a quantity is 79 cents. This is the one I probably would have selected:

EEU-FC2A221L Panasonic Electronic Components | Capacitors | DigiKey

and it's $1.11 each in 25 unit quantity. Given that it is hours of work to remove and reinstall the dash, or at least would be for those of us who don't do it all the time, saving a buck on the one replaced component isn't a gamble on quality versus price that makes a lot of sense to me.

 

ok, if paying a buck each makes you feel better go crazy. There is information on the net of using between 120 and 220uf so the tolerance doesn't seem to be too tight. I can tell you I have replaced 2 of these in mine, both were dead, blank and now they are both working. I have one more that needs to be fixed but its the kids and I refuse to pull his dash for him, he can do it when he is ready. And since this job is so easy I may make him solder it too. Easy lessons with a soldering iron don't come around very often so I will make good use of this opportunity. I can pull the dash in an hour, in fact I find putting it back in to be more than a pain in the a$$ then pulling it.

My final message to my fellow Prius lovers is, if you have a cluster problem, pull it and swap this cap out. Put the dash back in and hook up the electrical connectors except the screen connectors, you can leave those off and see if it works. If it does, continue assembly and be happy you saved 150 bucks, take momma out for dinner or bring some steaks home for the grill to celebrate. You have a Huge win!! If it still doesn't work, pull it back out and send it out and pay the 150 bucks and still save a ton over the stealership.

Just remember to Windex the fingerprints off before you put it back together

My latest score, 500 bucks. Brought my jump box and drove it home! (1 leaking module)

 

While I would also recommend buying known good capacitors from known good manufacturers sold by known good distributors, I would agree that there is no need to go overboard. No need for a 100V cap in a system that will never see anything over 14.5V. The caps get a lot cheaper in lower voltage range. 16V or 35V (if you are paranoid) is more than enough. Also, for us electronic tinkerers there is almost never a need to by caps. If you are anything like me, you will have piles of them salvaged from high quality gear, like hi-fi systems, PC power supplies, various electronic "garbage" like that. We know how to tell caps are not bad (we have eyes, meters and information), so my Prius is now sporting a 220uF cap from a high quality PCB (don't remember what it did, but it had high quality electronic components in it that involved audio paths). It's a brand name part, is 35V tolerant and works great. I have posted pictures of my repair elsewhere in this thread. Unfortunately, the name brand is not visible and I do not recall what it was. But I know I would not have salvaged it if it weren't something good and I know I have tested the cap also.

So, yeah, don't sweat it, go in there and do the repair. It will be fine. and even if you get the most expensive capacitor on DigiKey, it will still be almost free compared to the next least expensive option.

 

Actually I screwed up the part lookup it was 105C, not 105V. The equivalent cheapest Digikey 16V part at 25 units is actually 29 cents (42 for quantity 1):

EEU-FC1C221 Panasonic Electronic Components | Capacitors | DigiKey

So while those caps are still very cheap and from an unknown manufacturer, it wasn't quite as bad as I originally thought. The flip side, getting the new name brand part only costs 28 cents more (buying just one), not a dollar. Also while the 100V rating is overkill for voltage, it does bring along a larger estimated lifetime at higher temperatures (rated at 105C). 16V caps are typically 1K to 2K hours but the 35V part below is 4K hours (and the 100V part was 5K hours):

EEU-FM1V221 Panasonic Electronic Components | Capacitors | DigiKey

It gets pretty hot inside the dash, although nowhere near 105C. It wouldn't hurt to overrate the part a bit. Toyota didn't and look what happened.

I don't have ESR or capacitance meters and so wouldn't reuse a cap in an application like this as it could only be visually inspected before installation. For me, too much time investment in taking the car apart and putting it back together to use anything other than a new capacitor. Fine to stick used caps in a radio or any other easily disassembled, and not life critical, application.

 

I meant to say 220

 

Been so many good comments but I will add my two cents. This is definitely a do it yourself project if you are comfortable with a soldering iron. The dash comes apart very logically. I took notes on what order I took the dash components apart which made reassembly easy. The problem for me was a 25 cent capacitor on the circuit board that I removed and reinstalled with a higher rated one. The entire repair took me two hours from start to finish. There was no visual damage to the bad capacitor. I just replaced the one that everyone said was the likely suspect. Not a problem since.

 

Hope you didn't leave the old cap in.

 

Have not been on the forum for a while. I just wanted to follow up on my 2017 post. I did the fix as described above and I have not had any problems with my combo-meter since. I did not change the IC. So yeah, it was the capacitor change that fixed it. It turns out that electrolytic caps have a lifetime of about 10 years.

 

$2 online 220uF capacitor, having the skills to 1) disassemble the dash 2) unsolder and resolder ..
1) U migth want a $10 plastic pry bar set (patience is mostly the thing) -- be prepared , UV light, time, temps, the plastic is brittle, the vents can and will crack and break , but can be glued to a reasonable aesthetics afterwards .. 2) if u have spent time on the job soldering, it will be no prob. - if u spent time as a hobby soldering or it has been long time since, it is a bit more
difficult but its mainly heating and removing 100uF (which loses its charge and no longer has that capacity) and carefully replacing the new 220uF in its place , it doesnt have to look pretty since no one will see it ..