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AVR 635 Not Saving Settings Any More

post #1 of 52
Thread Starter 
My AVR will not save my audio/video input setup any longer. Whenever the power cable is unplugged, it reverts back to my setup from like 2 years ago.

How can I get it to save my new settings??

post #2 of 52
The memory cap needs to be replaced. It's a shame that HK still uses this method for memory retention. I have no idea what a shop would charge for this, but the part is about $12 from HK.
post #3 of 52
Thread Starter 
Thanks for the reply - I am surprised that it still has my settings from a couple years ago...

Any idea where I could find a schematic or location of the capacitor? I would be interested to see how difficult of a solder job it would be.

Also - do you know where can I find the replacement part from HK?

post #4 of 52
Just checked the SM. Component is C557, located on the DSP board. The DSP board is the board with all the digital inputs, as id'ed from the back panel. It is a 0.047F, 5.5V cap. HK part number is H03-CEZXA0479MN-0. I believe HK has a new replacement number for it; their tech support can give you the number of the parts dept. I got my caps from ebay, just search 'memory capacitor'. The the one HK uses, looks much different.
post #5 of 52
Thread Starter 
I found the cap on the DSP board and replaced it with a memory cap off of eBay (same .047F/5.5V) and still no memory on this thing...

Any other ideas or do I need to re-evaluate my solder job
post #6 of 52
Does it still recall your old settings from a couple years ago? This is strange...
post #7 of 52
Thread Starter 
No - I performed a complete processor reset so it doesn't remember any settings.
post #8 of 52
Were you careful in observing the polarity of the new cap? Put the + terminal in the '+' hole? If you did, it sounds like you have another problem. The SM only refers to this fix for the problem you reported.

The symptoms my 435 showed was losing it's digital input assignments. Honestly, I never checked to see what other settings were lost, but it seemed like the cal values were still ok. But I'd usually go to watch a DVD and get no audio, so I knew the digital input had reverted back to factory default. It did this ever time I switched off the main power switch, which I did regularly when dusting it (I move it around alot for a thorough dusting).
post #9 of 52
Thread Starter 
I took it apart again today and soldered a new cap in there (I got 5 with the ebay auction...).

I made sure the polarity was correct and that the solder joints were good (i.e they flowed well).

We powered it up and went through the following sequence:

1. Entered some settings (like naming one of the inputs - changing the digital audio source, etc.)
2. Powered it off (into standby mode)
3. Powered it on - make sure the settings were retained
4. Power off
5. Unplug the unit for 3 - 5 seconds
6. Plug back in - all settings were lost (name of the input, digital audio source, etc.)

Seems like there is another issue with the memory circuitry or something.
post #10 of 52
Yep, sounds like there is another issue with the memory settings. Or maybe the EBay memory caps aren't right for this app. I'll try mine to see what happens.
post #11 of 52
This probably won't make you feel better, but I just verified that my 435 was also NOT fixed with the Ebay memory caps. I'm sorry for recommending them without checking to make sure they actually fixed the problem. Either these caps are bad, or there is something special about the ones HK uses. I'm sure you noticed the huge difference in appearance/type. I'll report back once I install the expensive HK part.
post #12 of 52

I have the same problem, did you ever get a chance to install the expansive HK capacitor and did it fix the problem?
post #13 of 52
I just received my caps yesterday, so I should have results by the weekend. I'll post asap, as I too am wondering why the ebay caps don't work.
post #14 of 52
Looks like the HK part is needed. Did the replacement last night, set it up with a digital input to CD, left the AVR on CD input (default is usually VIDEO2/analog when it loses memory), pulled the plug on it this morning, etc. Fires up on CD, still looks for OPT1 signal before defaulting back to analog. So looks promising. I'll give it a longer loss of power later today to make sure.
post #15 of 52
Settings retained after pulling the plug for 30 minutes. AFAIC, it's fixed and the HK part is needed. Sorry again for thinking any 'memory cap' would work. I will x-ray the failed HK part and see if there's any hidden circuitry within.
post #16 of 52

Thanks very much for sharing the information.

Happy to hear that it works for you, with your provided information hopefully it will work for me too; I will order the part from HK and try to fix mine. Did take pictures of the board where the capacitor sit? If you did, sorry to bother you again, can you post some pictures?
post #17 of 52
Sorry, no pictures. But it's easy to find/identify. The boards in the 435/635 are arranged in a stack, seperated by metal spacers. The digital board is the second from the top. You'll be able to remove it, along with the top board which has two ground wires running to the digital board. The cap is a little away from the center of the board, away from the back (id'd by the digital connectors)and to the inner edge. It's a black square, about 1/2" x 1/2".

BTW, it is made by a company named SmartCap. Their part number is "scda5r5473v". Couldn't find a US source though. I x-rayed it and found nothing special inside. I still don't understand why the ebay caps don't work.
post #18 of 52
I fixed mine with the part I got from HK part dept. I turned off the main power for about an hour, turned it back on the setting still there. I also did the firware update to 4.15, everything saved.

Thank you.
post #19 of 52
I changed the memory cap for my AVR 430 but I tried to use memory cap from another H/K amp (p.n P10790-ND). Did not work, so now I've ordered the part from H/K.

But I took some pictures, maybe these might help somebody...
post #20 of 52
And the last picture...
The pictures:
1. AVR 430 opened
2. The board above the DSP board
3. The board above the DSP board detached
4. The DSP board
5. The memory cap position under the DSP board
6. And the memory cap

H/K Service Manual's file name is harman-kardon_avr-430_630_sm.pdf
post #21 of 52
My AVR-635 has not retained memory for some time. It has been in storage but I would like to use it again. My temporary, low end Sony is gutless and not cutting it. I called HK parts and the thickly accented gal that helped me said they did not have the part however I was not comfortable she was giving it 100% so I waited 15 minutes and called again. The second person I talked to also said the part was gone however they had a substitute. $13.96 including shipping. I will post my results next week after we install the part.

THANK YOU to the previous posters for some very helpful information.
post #22 of 52
I have the same problem with my 635 where the memory is lost all the time when the power glitches in the house. I called HK today and talked to someone who couldn't speak English very well. Anyway, I gave them the part number H03-CEZXA0479MN-0 and as you can guess they are out of them and won’t get any more. I googled H03-CEZXA0479MN-0 and found a place that has a replacement part, and that replacement is also obsolete and there is another replacement part P10790-ND. My concern is in the above post that parts with similar specs don’t work in the HK. I called Encompass any it will take several weeks to get the part P10790-ND since they have to order it first and they need a minimum order etc.
I googled P10790-ND and found them selling at Digikey for $1.58 in stock.
I don’t mind paying Encompass but I don’t want to waite 3-4 weeks since I have time next week and I want to fix this when I have time. The post above says the part is 0.047F but the Digikey part is 47MF so they should be the same but does anyone know if this will work? I don’t know if the digi key part is the same as the Encompass part since the Encompass part isn’t pictured. Based on what I read above, there is a concern about parts with the same specs not working. I don’t know if the caps from Ebay were just bad parts or for some unknown reason they are good but something is different enough that even with the same specs they didn’t work. I the obvios possible reason is if the caps were installed backwards but this concern was identified and ruled out.
Any advice and what to order and from where?

post #23 of 52

I suggest you look at the actual part in your receiver to see if it looks like the P10790 part. I don't recall what the HK part looked like, but that Digikey part looks like the memory cap that I bought from EBay that DID NOT work. Maybe send Rick a PM to see what his replacement looked like. Good luck.
post #24 of 52
HK support (India) couldn't find a replacement part but the one I found (P10790-ND) HK support did eventually say it was the replacement part I needed. I did decide to order it from HK so I'll know what it looks like and if it works in 5-10 days. If I had called before 1:00PM, I could have gotten it shipped in 2 days but for some reason I couldn't get it shipped faster unless I call back the next day before 1:00PM. I just hope that with the language barrier I get something that fixes the problem.

Below is a link to the digitkey part but I can't confirm the HK part is the same til I get it.


Is there any trick to removing the two boards to replace the cap? I probably won't open it up and look till I get the new part next week. From the pictures it looks like I only need a screw driver and the only thing I have to unsolder is the cap itself. Is that correct?

post #25 of 52
Yes, that's correct. Mind you, I worked on an AVR-435, the little bro to your 635. But I suspect the builds are very similar. Just a bunch of ribbon cables to undo, and some screws to remove. Take your time, take pics before you disassemble in case you forget what went where. That's a step I always regret not doing myself. Good luck.
post #26 of 52
I got the cap the other day and can confirm it does look exactly like the digikey part I posted in the link above. I was able to disassemble the 635 and replace the cap and get it back together. The good news it everything appears powers up OK but it still doesn’t keep the memory.
I followed same steps above:
1 Entered some settings (radio station.) (keep unit on to charg cap)
2. Powered it off (into standby mode)
3. Powered it on - make sure the settings radio station settings saved
4. Power off
5. Unplug the unit for 3 - 5 seconds
6. Plug back in - settings were lost (radio station)
Skiier3_9, did you ever fix yours and if so how? I did get the replacement cap from HK directly. Also, I can confirm it was put in correctly and when I turned it on, I left it on for about 5 min to give the cap time to charge. I do not have a schematic but any large capacity cap either takes time or large current to charge.
Any ideas?
post #27 of 52

That was my experience exactly. I even left the replacement cap in overnight, and it still didn't hold settings. I don't understand what is special about the original HK caps, but these new style 'memory caps' do not work. Someone needs to tell HK that they don't work. You did notice that they look much different than the original 'smart cap' that was in there, right?
post #28 of 52
I have been talking to HK today. I even got through to people in the US who seem to want to help. They are going to get back to me in a day or so about the replacement. My original cap looked like your picture, a black cube shaped cap. The new one is round and looks lik this:


I did get my cap from HK as a replacement so they are looking into the problem. I'll let you know how it goes.

post #29 of 52
I never heard anything so I took it back apart and tacked some leads on the cap and reassembled it. When I turned it on, the cap would have 4.74 volts across it immediately after turn on. There is no charge time I could measure with a DVM. Turning it to standby did not affect the voltage but once I turned it off it immediately went to 2 volts and then would slowly go down from there. It doesn’t remember settings even if turned off for a brief time.
The replacement part that I found works is a AVR3312 by Denon. The 2013 models have been announced and there are some good deals on the 2012 models.
post #30 of 52
LOL! How did you get that receiver to fit in that small space? Congrats on the new receiver, it's a shame even HK doesn't know how to fix this annoying problem.
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