AVR 635 Not Saving Settings Any More - Page 2

The Denon is awesome! There are a few things I miss about the HK like the display can be read from across the room but the Denon does some cool things like built in bi amp, internet radio, HDMI etc. When HK support recommended I add a UPS, I knew that would work but I figured I would put the $ towards something new with the new features. The HK is much bigger and heavier then the Denon so maybe the Denon is using class D amps, I really don't know.

I bought a capacitor off of ebay that looked like the original and followed the steps in this g+ public photo album and the AVR-635 memory works through power failures now.

https://plus.google.com/photos/115293138644162632086/albums/5449040136236449665?banner=pwa

So the one you bought looks different than the replacement in the last pic?

Yes mine looked exactly like the original (rectangular and black) not like the round one in that guy's g+ album. The ebay seller I used at the time no longer sells them though. Sounds like the round one worked for him with a little difficulty getting into place.

Some observations based on previous posts:

The Service Manual for HK DPR1005/2005 has a Tech Tips page HKTT2003-01 Rev 5 which addresses the memory loss complaint for numerous models.

The entry for AVR435/635 shows replacement part H03-CEZXA0479MN-0.
The entry for DVR1005/2005 shows replacement part CEZXA0479MN-5.
I strongly suspect these are the same parts, just with differences in the numbering to keep track of how many are ordered for which model. I base this on experience ordering parts from HK in the past which are 'substututed' with sometimes wildly different number but are actually the identical part.

From what's been said here, these physically appear to be a Samsung "Starcap" part SCDA5R5473V. ('SmartCap' was incorrectly mentioned by a previous poster as being the manufacturer...different company altogether.) The Samsung parts are indeed rectangular and plastic. There's a datasheet PDF for them here: http://www.datasheetarchive.com/SCDA5R5473V-datasheet.html. I recommend folks look this over. It has a number of graphs and cautionary notes regarding installation.

Basically, the caps should have sufficient charge time...at least an hour. According to the DPR service manual, the part is connected (via diode isolation) to the +5v supply, then to the center tap of a resonator that forms the clock circuit to the receiver's microprocessor. This seems a really strange circuit, so unless the schematic is wrong, there's no real DC 'charging path' for the cap. So charging is happening by a very high impedance pulse source, meaning it will take quite a while to form a charge. My own experience with a new part is that it can take a day or more before it really holds memory up well.

Note that for most models, the Tech Tips point out that without power, 2 weeks (4 weeks for DPR models) is about the normal the memory time expected.

Part number P10790-ND is listed in the Tech Tips for a number of HK AVR models. This is a Digi-Key (electronics component supplier company) number for a Panasonic EEC-S0HD473V
series SD double-layer 'supercap'. These are available in a 'stacked coin' package with vertical or horizontal leads. The posts lead to some pictures of the horizontal version being installed in an AVR, but the vertical ones (with V at the number end) would be closer to the original form factor and lead spacing. The 'electric double layer' is the same technology as the Samsung part, just packaged differently. The're also under $2, so vastly cheaper than the Samsung part from HK.

Hi guys,

Thanks for this thread, I really didn't want to retire my AVR635, I love the power and sound quality in this little beast.

It has been losing settings for over a year now, I used a UPS I had laying around to keep settings intact. Earlier today while working on my AV gear I unplugged the power cord from the back of the reciever by accident for about 30 seconds, and &%$&%$, it lost all the settings yet again!

I feel obligated to post my results since if it weren't for this thread I would not know what was going on with it, so thanks everyone that contributed and I hope my input helps someone else solve this ugly little problem. Also thanks to digikey!

I read about the guy/s earlier in the post that used the HK reccomended super cap that had the same rating that did not work.

Well, I thought about making a 5V supply with a lithium battery and charging curcuit, but first I wanted to try putting several of the replacement supercaps together in parallel since maybe the new ones were not up the same snuff as the original as often electronics are not.

I paralleled 4 of the digikey $1.50 units and wired them in to replace the old supercap. You can see my picture, the extra black and red wires are so I can add a 5V supply later incase this attempt did not work.

http://www.digikey.com/scripts/DkSearch/dksus.dll?lang=en&keywords=p10790-nd&WT.term=p10790-nd&WT.mc_id=Capacitors&WT.medium=cpc&WT.campaign=Capacitors&WT.content=text&WT.srch=1&WT.source=google&cshift_ck=7319abcb-a331-4571-bf36-3e0b885e37d0cs906208360&cur=USD

Well I programmed a couple inputs into the reciever, tested them. Then I unplugged the reciever from power for about 15 minutes. Plugged it back in, and it remembered, so far so good. I'll chime in later if failure occurs again but it seems fixed.

Sow how is the stacked Memory Cap fix holding out?

I was thinking about just doing a bigger Cap. DigiKey has a 220mF 5.5v 120Ohm one available. If I calculated it correctly you ended up with a 188mF 5.5v 30ohm (Capacitance adds and resistance divides) I think the 30ohm might make it charge faster but I'm not sure.

Thanks will try your method, as the correct part does not appear to be available any more and HK is clueless.

Edit: Just got around to doing LightFlightDave's method. Took me a lot longer than I thought it would, but all is now good. Unplugged several times for a hour or so, then for 9 hours with no issues. I will be unplugging the unit for several days as a final test. Will update here in a month. If it's still good then I'll consider this solved.
Edited by moglia - 12/16/12 at 7:14am

I did end up using the 220uf Supercap http://www.digikey.com/product-search/en?x=0&y=0&lang=en&site=us&KeyWords=604-1010-nd I used the legs that I had cut off of a resistor to extend the leads (they are just a bit to big to fit through the holes on the board. Worked great the memory holds now.

Crazy how this thread is still active. Several years ago, I had moved my AVR 635 to my basement in favor of a much less formidable Yamaha 663 in my main system, and since then, the Yamaha has been nothing but a solid, terrific performer, while my AVR 635 has continued to be nothing but a pain in the neck with the lost settings, Logic 7 bugs, etc. I finally just retired my AVR 635 for the Yamaha 663 (with a new Yamaha 671 in the main system).

Between the lack of HDMI, actual defects, quirks, etc., happy to retire the 635, notwithstanding that it probably weighs more than my 2 Yamahas combined. From lack of reading, I have no idea about the current reliability of H/K receivers, but these receivers from several years ago were unfortunately very unreliable.

I was going to try the CAP SUPER 0.22F that you mentioned but did not remember reading of any successes. Would have saved me a lot of time chaining 4 CAP SUPER 0.047F 5.5V RADIAL in parallel. It works so in end all is well.

Unreliable is right! It was and will be the last HK equipment I ever purchase. First an issue where it would cut out when it got warm. Repair center fixed that under warranty, 8 months later same thing. I finally installed a small quiet PC fan to fix it myself. Then this settings nonsense. This unit is my 3rd and least used system that I keep in an extra bedroom. Next problem it goes where it always belonged -- the garbage.

Since 2007 I've gone with Denon for all my gear. Costs more but a much nicer warmer sound and no nonsense. Ta ta Harman.....

I guess I'll keep this thread alive since I too need this fix for my HK DPR1005. I'll try the 220uf super cap and post my results in the next few weeks. Thanks to all for the very helpful information & pictures.

Hi,

I soldered on wires similar to this pic posted earlier and placed them [with my cap array on the end] so if it ever needs to be redone only cover removal will be required.

Thanks for the tip Moglia.... I will do just that!

I had the cover off the other day to peer into the innards and the disassembly for my AVR looks daunting. I did a system reset hoping it might help or affect the problem, but no luck. I've put it back in service temporarily waiting until I have a day to work on it. Thanks again for all the info I've gained from this thread.

Unfortunately the part I received from HK DID NOT solve the problem. I had a local repair shop install the part. My 635 briefly acted like the problem was solved but it quickly reverted back. For me, this is a real problem because my 635 locks up roughly every 2-3 weeks. I hate the thought of throwing away (recycling) such a powerful and great sounding receiver but I am very close to doing just that. I have a relative that distributes Denon and Marantz products so I have access to a replacement at extremely good pricing.

RickGr44, Go with the Denon

Compared to Denon , Harmon Kardon is OK at best. Denon's trademark as it were, is a warm sound accomplished via great mid-range and smooth low end. Or at least that's my experiences.


SteveHoward - the task is a bit daunting as you said. Allow yourself 1-3 hours of uninterrupted time , take a lot of before photos at every step and go slow. I am totally an amateur as well with the stuff but it worked out. I found a de-solder braid better than a sucker for this procure

The HK635 was goofy all right. I have 1. Only use the direct inputs and bypass the processor.
There is an old long thread about the 635 here somewhere. All the other HKs I have (most older but there is 1 HK245) still work excellent and I hang onto them because they have features that are only available the very top of the line models of all other brands nowdays, plus the amp sections are way underrated power and distortion wise.