Faulty Yongnuo YN468 repaired

At home, we bought a good looking flash, the YongNuo YN468 that worked flawlessly... for about three weeks.

Then it started firing once every 5 or 8 trigger commands, no matter if they are sent by the camera, the remote receiver or the test button on the rear panel of the flash.
After a few weeks resting in a drawer, the internet started to report the same failure on other flash units time and again.
Somebody found the problem: a small capacitor in the flash head. Later, he reported that the flash worked fine after the replacement.
Other people replaced the capacitor and reported success, so I decided to take the plunge.

End result: it is working fine now, and I'm sure the original capacitor was open.

I will post a brief description of the repair and some pictures to show how to do it.

The faulty capacitor is marked
473J
630V
According to the conventions, it means 47 followed by 3 zeroes: 47000 picofarads, or 47 nanofarads (nF) or 0.047 microfarads. J means a tolerance of plus/minus 5%. The working voltage is 630Volts.

In areas with good suppliers of electronic parts there will be no problem.
Perhaps small capacitors at 630 Volts are harder to find, but people in the web report that capacitors at 400V work fine.

In my area, the best I found were capacitors of 22 nF rated at 400 Volts with a tolerance of +/- 10%. Two of them in parallel would sum 44 nF, but due to the larger tolerance, with a bit of luck I found two actually measuring 23.5 nF which means 23.5+23.5=47 nF

To replace the capacitor you need:
- A small phillips screwdriver
- A Small flat blade screwdriver
- Thin Needle Nose Pliers to bend the wires
- A small Diagonal Cutter
- A 25 Watts soldering Iron
- Thin (#22) Electronic grade rosin core solder
- The spare capacitor(s) of the same or similar size of the original
- Silicone glue to replace the rubber caps (see below)

Procedure: ( Click the images to enlarge )

IMAGE LINK: http://rpolitsr.rafael​polit.com/potn/yn468/I​MG_0212_800.jpg

• Locate the two holes and the two rubber caps on the flash head.
  
• With the flat blade screwdriver, carefully remove the two rubber caps, they are glued-in.
  
• With the same screwdriver remove the four metal clamps below the rubber caps
  
• With the phillips screwdriver unscrew the screws of the flash head.
  
• Remove the upper head cover and the clear flash diffuser.
  
• The insulated wires and the white plastic behind the small circuit board can be damaged by the soldering iron heat, so unscrew the board. You may ask some help to hold the board while removing the capacitor and re-soldering the new one in place.
  
• Re-assemble the flash in reverse order: Be sure that the zoom motor will move the flash light freely.
  

IMAGE LINK: http://rpolitsr.rafael​polit.com …n468/IMG_0140-141_800.jpg

IMAGE LINK: http://rpolitsr.rafael​polit.com/potn/yn468/I​MG_0144_800.jpg

IMAGE LINK: http://rpolitsr.rafael​polit.com …n468/IMG_0147-231_800.jpg

IMAGE LINK: http://rpolitsr.rafael​polit.com …n468/IMG_0228-232_800.jpg

IMAGE LINK: http://rpolitsr.rafael​polit.com/potn/yn468/I​MG_0204_800.jpg

I'm not alone with another problem of the flash:
Theoretically, the pilot light lit green while charging and red when the flash is ready to fire.
My flash has the red light always lit, I need to wait (ten seconds?) between flashes just to be sure, and change the batteries before they are weak.

I opened the flash body to reach the red/green LEDs, but without instructions on how to remove the display safely, I opted to replace the covers and live with my ever lit red indicator.
I think it has no effect on the normal operation of the flash, or a least it is my hope.

( Click the images to enlarge )

IMAGE LINK: http://rpolitsr.rafael​polit.com/potn/yn468/I​MG_0225_800.jpg

IMAGE LINK: http://rpolitsr.rafael​polit.com/potn/yn468/I​MG_0238_800.jpg

I was looking to order the yn468 today, would you still recommend it?

You get what you pay for. Some people (myself included) only learn this lesson through experience. The money you spend on an item goes toward the parts to build the item, the skill to build the item, the company which backs the item (warranty, customer service, returns, etc), and the profit of the company making the item.

There is a reason a 580exII costs $450 and a YN-XXX costs $50-$100. Shortcuts have been taken, cheaper parts have been used, people haven't been paid as much, etc, etc.

The only person who can make a decision about what flash to purchase is you. Never take recommendations.... take evidence and make your own decision based on your needs and wants.

I am not complaining about YoungNuo.

The flash and other accessories work for me.

There was a specific problem that we addressed with success and that is what I am sharing here.

I would like to see this thread with posts describing real problems and the solutions people find for them to help others.

Bashing the name is not the pourpose of this thread.

Threre is a more generic thread about the YN468 flash with a lot of posts about prices, budgets, availability, problems etc.

This is a lot more detailed than the same fix I posted a week or so ago, hopefully this one gets stickied.

About the price, someone like me can afford a pretty good $100 flash, but can not justify spending $450 on a great flash. So in my case, it comes down to either having an off camera flash, or not having one. The good one will do about 98% of what I would ever need it to do, for me the extra 2% is not worth $350. Mine has worked fine since christmas, but I might do this "repair" anyway, just so I am not stuck later with it not working.

rpolitsr- do you have any links to these fixes? I don't know anything about electronics, and want to make sure I got the right capacitor if I order online. Thanks

Brew

tsbrewers wrote in post #11849613
... rpolitsr- do you have any links to these fixes? ...
Brew

Well, I read your post, followed the link to your thread and have read the captured screen that you included.

After reading it, as I am an engineer in electronics, I used my experience to open the flash, replace the capacitor and test it.

All the above pictures are mine, and they were shot while my flash was being repaired.

I have written the description of the process too. I hope that the detailed image sequence will be of more help than the writing, so the description was as short as practical.

---------

In regard to your flash, don't fix it if it is not broken. My guess is that a small although significant number of YN468 have the faulty capacitor; most of them should be free of the defect.

Rpolit, I had the same issue with my YN-560. If you read a bit in the YN-560 thread, you'll see that I'm not alone.

Hopefully this thread will get enough exposure so people who have any YN flashes that has broken will know how to repair it.

Thanks for the perfectly explained tutorial, it was well written and surely, well pictured

I have probably only shot about 500 pics with the flash, so we will see if it keeps working. I picked mine up from dealextreme as it had all positive reviews at the time. I happened to check back in and noticed people starting to have problems, and noticed the capacitor fix.

Can you explain a little why the 400v one works? Or what this does in the first place? Would someone be better off getting one as close to the original one as possible, or is it a better idea to use the 400v one? As you can see, I know nothing about this stuff, so this is mostly to just learn something new today.

Again, thanks for the write up and clear instructions.

Brew

Thank you Rivest, and sorry to hear about your flash. Probably the flash head is very similar to the YN468 and the same repair may work if the symptoms are the same.

Some skill is desirable for a safe work with the soldering iron, but I would say that the replacement of the capacitor is not difficult.

tsbrewers wrote in post #11851965
... Can you explain a little why the 400v one works? Or what this does in the first place? Would someone be better off getting one as close to the original one as possible, or is it a better idea to use the 400v one? ...
Brew

The voltage rating of a capacitor is the max. voltage that it withstands across its terminals. If you go above that voltage, the capacitor can be damaged. If you are below the rated voltage the capacitor works in the safe side.

For this work, if you can find a capacitor rated at 630V by all means use it.

I measured the AVERAGE voltage across the capacitor: 320 Volts so it seems that a capacitor rated at 400V will work. In the worst case, it is still possible to have a PEAK voltage greater than 400V, that's why the lower voltage capacitor is a good compromise only if the original is not available.

awsome job of documenting this! good work...

Sure, but a lot of that price increase is brand name and "what the market will bear," none of which has anything to do with the quality of components.

The Canon flashes are not made from the tears of angels and gold wire.

Sub'd!! And a big thank you...

Am hoping I won't have to use it, but just in case...

Just picked my 468 up this morning - am RIGHT about to unpack it and test it.. been a very hectic day at work, been itching like mad to pull it out, plug in the batteries and give it a whirl..

Thanks again in advance..

Dirk