Harman Kardon AVR 635 / 435 - Firmware/Software upgrade and memory fix

beachrodder

beachrodder

New Member
Here is the link to Harman Kardon's firmware / software upgrade page including a new version of the owners manual. Click on "Support page" , then on the next page click on "DOWNLOADS" . Your choices are then , "DOCUMENTS" , (this is the owners manual) and "SOFTWARE" , this is the upgrade with the instructions.

I am providing this to help anyone with a Harman Kardon AVR 635 or 435 to upgrade their system. When you download this software it comes with a page of instructions on how to perform the ugrade.

http://www.harmankardon.com/estore/...stion=avr+635&pageSize=1000&_requestid=227173

When you download it everything is in a FILE FOLDER named "Harman Kardon" , the instructions are in the file named : " upgrade_Product 56,132 41,453 Adobe Acrobat Doc... 25/10/2009 1:2... 1F3E2976 ".

Also on the instruction page it says in a black box : " This upgrade includes the benefits of all previous software updates, as well as an added correction to make certain that configuration settings remain in the system memory. "

I did a test today where I unplugged my AVR635 for 1 1/2 hours and it still had its settings when I plugged it back in. That did not happen a few weeks ago when my house lost hydo electric for an hour and a half, after that it had lost its setttings. From my reading these units should hold thier settings for two weeks before loosing them. Considering that my AVR is now ten years old I would expect a shorter memory holding time due to the 10 year old super capacitor (capacitor number C557).


It upgrades your AVR 635 to software version 5.15 or AVR 435 software to 4.15 . This is the latest upgrade available , I called Harman Kardon today (March 5 2015) and confirmed this.

I did the upgrade and had no problems. Make sure you read the instructions once before doing it and then again as you do it step by step.

You will need an RS232 cable to do it, make sure it is not a "null modem" RS232 cable or it will not work.

For Canadians this is not on the Canadian website, it is on the United States website. The lame useless Canadian website doesn't even recognize that an AVR 635 exists. (I am Canadian by the way). I can't tell you how many times I searched and searched and searched that Canadian website for it.

Hope this helps someone.

John

**** UPDATE : I SPOKE WITH THE UNITED STATES HARMAN KARDON CUSTOMER SERVICE TODAY ( AUGUST 4TH 2015 ) AND THEY TOLD ME THAT THEY NO LONGER HAVE THE SOFTWARE UPDATE ONLINE. TO GET THE SOFTWARE UPDATE YOU CAN CALL CUSTOMER SERVICE AT 1-800-422-8027 AND THEY WILL E-MAIL YOU THE SOFTWARE UPDATE. ****

Here is the link they sent me to the updated software:

http://mobile.harmankardon.com/estore/hk/us/support/supportDU.jsp

John
 
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Adding on, I strongly suggest anyone doing this use a computer that has a real serial port, not a USB-to-serial converter.
 
To whoaru99 yes you are right.

They even specifically mention in the instructions, not to use a computer with only a USB port because it may not work.

I was able to use my 2008 desktop computer that has a RS232 port on the back.

They also say in the instructions not to use a RS232 cable longer than 25 feet. These cables seem to be rare around here now, but I found one at a local computer store that was 25 feet long and it worked fine.

Thankyou for mentioning that whoaru99, much appreciated. :)
 
For those curious about this, monoprice has serial cables in various lengths for $2 - $4.

Murray
 
That should help people out Murray. :)

I had a hard time finding one , I must have called about 5 or 6 places around here before I found one. And I think they only had one lying around.

John
 
Well I thought I better come back here and report that the software upgrade did not fix my Harman Kardon memory problem properly. Its only fixed for very short power outages . Considering how often the power goes out where I live, I have decided that I am just going to buy an uninteruptable power supply ( UPS) . I am considering the Tripp Lite ECO 850 LCD which I'll use for both my desk top computer and the Harman Kardon.

It is what they call a "super capacitor" that is supposed to hold the memory. Considering that I have been told that capacitors should last close to 15 or 20 years and that this receiver is only around ten years old I find it hard to believe that the "super capacitor" would be shot ( maybe not such a super capacitor after all, LOL). Granted I bought this receiver used but still, shouldn't that capacitor still be good?

This is my first Harman Kardon, is Harman Kardon a good brand? Has anyone else had this memory problem and got it fixed? If so how did you fix it?

One idea I have is to remove the "not so super capacitor" and replace it with a rechargeable button cell battery in a battery holder so it can be easily replaced when it dies. I would just install the battery holder in an easy to get at place near the top inside the receiver and run wires down to where the "super capacitor was on the circuit board.

I would be interested in hearing from anyone with their experiences or thoughts on this.
 
I, too, have an HK with the memory problem. By contrast a Kenwood Basic tuner I retrieved from a our storage unit had station presets intact after maybe 10 years. It uses two AA batteries for backup power.
 
Yesterday I replaced the memory backup supercapacitors in a Harman Kardon AVR 125. It was very easy and it holds settings in memory for at least an hour with the unit unplugged (the longest time I have tested it so far). Before the memory settings disappeared instantly when power was disconnected.

On this particular receiver the memory capacitors, two in parallel, are located on a board behind the front panel. I took out the mounting screws and the board was able to lean back enough for me so desolder the old capacitors and replace them with new ones. The old capacitors were 0.47 F and the new ones were 1.0 F. The new ones were considerably larger and the board had to flex a slight amount when it was put back in place. If I had it to do over again I would put the capacitors on the back of the board where there is much more room. The new capacitors are Panasonic brand, made in Japan, the originals no-name, probably Chinese.

The memory storage capacitors look completely different than the hundreds of other capacitors in the unit and are easy to identify. If you have memory backup problems this is an easy repair, at least on this model.
IMG_2770.JPG

IMG_2765.JPG
 
botrytis said:
Only a day?

As I said, it may be the old FPGA design....
Click to expand...

I only left it unplugged for a day after the repair because I wanted to listen to it! It may keep the settings for much, much longer. Previously, unplugging or even the slightest power line glitch meant everything was lost.

Yesterday I did the same fix on an AVR 435. Again, the repair was successful. The 435 was a lot more involved than the 125. Lots of ribbon cables and inter-board connectors to remove. The memory capacitor is on one of the lower boards. The original capacitor on the 435 was a 0.047 F. The replacement a 1.0 F. All the memory capacitor does is store electric charge to keep the memory data alive - it's not involved in any tuned circuits and doesn't carry any signal so the exact value makes no difference. The replacement stores 20 X more charge so it should have more reserve time. Sort of like replacing a AAA battery with a D cell. The smaller value was probably used by HK because of expense.

The only real problem I had was that the leads to the new, larger capacitor were too thick to insert into the circuit board holes. I soldered short lengths of wire to the capacitor leads, then inserted the new wire leads into the board and soldered.

I think the new capacitors will give longer service than the original. Why? Japanese-made components usually are higher quality, newly manufactured supercapacitors may be better than those from 15 or 20 years ago, and the larger capacitance should take longer to bleed down.

This easy repair should apply to a lot of HK receivers sitting in closets.
 
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