Harman Kardon Citation 19 (nineteen) needing some advice - diyAudio
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Old 14th June 2014, 08:57 PM   #1
KyleM is offline KyleM  Canada
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Join Date: Feb 2012
Default Harman Kardon Citation 19 (nineteen) needing some advice

Hello everyone,

So after reading some very good articles on how to upgrade the Citation 19 by H/K i decided to adventure into the world of DIY amp restoration.

Some background first though, I bought this amplifier locally, and when I got there he had already had the unit running. So when we switched it on and off, it made a slight pop, but noting to extravagant.
When i got home, I hooked everything up and upon initially starting the unit (cold start) it seems to make a very large thump that makes me not want to have my speakers connected. Also the LED indicators for sound go all the way on and the speaker drivers seem to fully push out then slowly return to their resting orientation. So I figure that the capacitors on this 30year+ amplifier have started to degrade and i have started doing modifications as seen in this forum: Harman Kardon Citation 19 Recap - AudioKarma.org Home Audio Stereo Discussion Forums

Now there is one thing that the user did not upgrade was the power supply boards as well as the capacitors on the power button.

So here are my questions for everyone:
1. What do you think is causing the leakage during the initial cold start?

2. I will replace the capacitors throughout the amplifier including the power board (2x 1000uf 25v axial). So, Which capacitors would be best for this application? I have been looking at nichicon VX 1000uf 50v +/- 20%

3. is it worth it to replace the diodes on this board? and furthermore, i have read threads about fast and soft recovery, but have not found a simple explanation of which is best, so advice would be appreciated.

4. Do you think it would be worth while to upgrade the ceramic capacitors that are located on the power button? (2x 0.01uf 1000v) and what would they be replaced with? eg. same vales or different capacitors.

Here is the manual i have been looking at for values: http://manuals.harman.com/hk/Service...eteen%20sm.pdf

I have already started by replacing the input wiring with 20 gauge copper and nice RCA connectors, and will be upgrading the capacitors later this month, on the L/R signal boards with Elna similic II and the capacitors on the transistors with mundorf m-caps.

So if anyone has anything they can add or some avice for me that would be great!
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Old 15th June 2014, 12:11 AM   #2
Art M is offline Art M  United States
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Join Date: Oct 2010
Location: SF Bay Area
Often the best results are achieved by first Repairing a piece of equipment to proper operation
and then having fun upgrading, modifying and replacing. There are many examples of "shotgun" techniques resulting in Additional problems that are never solved.
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Old 15th June 2014, 02:17 AM   #3
gofar99 is offline gofar99  United States
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Join Date: Jan 2007
Location: Arizona USA
Default Agree

Hi I agree that you should first make it function properly then mod it as it can save you a lot of grief later. As for the 0.01uf capacitors ....since they are operating at AC line voltage they should be replaced with type X2 ones of the same value. X2 capacitors are designed for that function and are available from many sources. They didn't have or use X2 ones when the amp was built. I didn't see one in the schematic, but many amps of that vintage have either a speaker muting relay or a soft start circuit that will preclude start up thumps. Often the relay contacts get dirty and can cause problems. On the rectifiers, I would leave them alone. They are probably slower ones but with proper filtering not likely to cause any particular issues. Something to check for the thumps is the switches. I have a Marantz of similar vintage and they misbehave if I don't use it regularly. Some DeOxit sprayed IAW the directions can do wonders in this area. Just aside... the amp looks a lot like a Kenwood I have.
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Bruce
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Old 15th June 2014, 06:07 PM   #4
KyleM is offline KyleM  Canada
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Join Date: Feb 2012
Thanks for the advice so far. I have used deoxit on the main power switch, with no noticeable change.

So to clarify, the amplifier works very well after the initial startup thump. I figured this thump would be due to the power supply capacitors not being able to hold a proper charge. So i decided that instead of paying for shipping twice or three times i would just bundle everything together into one order.

Now i want to change the capacitors on the AC line to X2 capacitors, but i can not seem to find a fitting value of 0.01uf 1000v. does anyone have a certain site that they use to source components like these?
unfortunately i have had to turn to the bay to find these values.
10pcs WIMA MKP10 0 01uF 0 01?F 10nF 1000V 5 Pitch 15mm Capacitor | eBay

I was looking at the Wima MKP series and it seems like it would work. Let me know what you guys think.
WIMA
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Old 15th June 2014, 07:51 PM   #5
KyleM is offline KyleM  Canada
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Join Date: Feb 2012
Also here are some photos so far, apologies for the dust

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