• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Recapping and restoring a Harman Kardon 330C

stuffguy612 said:
I stupidly didn't take photos of the underside of any of the boards on my unit and now have an issue. Can anyone explain what this ground(?) wire and cap is for and where it is supposed to go? The side that is connected is on the tuner board. Thanks again for bearing with my beginner struggles everyone.
Click to expand...

@stuffguy612 are these enough to answer your question?

IMG_0678.jpeg
IMG_0679.jpeg
IMG_0680.jpeg
IMG_0681.jpeg

Not all 330c have this cap + jumper, but that’s where it goes.
 
Not sure if this is common or a one-off, but when I was rebuilding the phono board I noticed that resistors R103 and R104 were 4.7k ohms and not 330 ohms as in the design. I am wondering if this was an intentional change in the factory or an error. Any ideas?

I ended up switching it for the specced 330 ohms and everything is sounding great, so IDK.

Thank you @dlucy for the amazing guide. I would never have picked up this gem of a receiver had you not made this guide. Saved a ton of work and research!
 
pronounce803 said:
Not sure if this is common or a one-off, but when I was rebuilding the phono board I noticed that resistors R103 and R104 were 4.7k ohms and not 330 ohms as in the design. I am wondering if this was an intentional change in the factory or an error. Any ideas?

I ended up switching it for the specced 330 ohms and everything is sounding great, so IDK.

Thank you @dlucy for the amazing guide. I would never have picked up this gem of a receiver had you not made this guide. Saved a ton of work and research!
Click to expand...

When I restore those boards, I use 330 ohm.
 
Any thoughts on replacing Q503, Q504, Q505, and Q506 on the tone control board? I had a bunch of left over KSC1845 and got a little ahead of myself. On second thought, I'm wondering if these need to be matched.
 
I watched the video and noted that he swapped out the transistors on the tone control board and didn't match them. So, I'm guessing it's fine.

@dlucy - Curious as to why the Q503, Q504, Q505, and Q506 transistors didn't make it into your recap and upgrade list considering that they are also 2SC1344E transistors on the noisy list.

Thanks again for your amazing guide!
 
Blue Shadow said:
We need to address an issue with the service manual for the HK330c. The board layout shows that C601 and C602 are installed opposite to each other, one ground toward the left and one toward the right side of the unit.

You, @dlucy, have a pic of a recapped PS board above showing the two small caps behind the large caps with the negative side pointing the same way. I just did my power supply early this morning and mine are the same and I believe I installed them exactly as removed.

Since this is your thread, I'll let you have the credit but with that you need to update your 330c encyclopedic knowledge base and spread the word as to the correct orientation of these caps and how it relates to the board layout drawing in the manual. Based on the diagram both caps have one lead on chassis ground and per the schematic this is the positive lead.

I was noticing that my machine doesn't have a turn-on delay and was learning about it in this thread: Harman Kardon 330c massive DC offset and hum at turn on and after recapping the PS, EQ and most of the main amp board, I still get instant sound. I did buy the replacement transistor to put in and have the resistors to check, but I did fail to buy a couple 1000/10 caps for the main amp board so that made for a nice stopping point. I'll do the tuner and the other boards in a day or two while I compile a parts order. No big hurry the amp works with those old, tired caps in it. Another note: the board says these are 470/16 caps but the ones in my unit were 1000/10, maybe another thing to look into.

Background on this unit is that it is a multi-voltage unit. Switchable voltage (internal) 100-120-220-240 and as expected switchable FM de-emphasis to be usable in US or Europe.
Click to expand...
You have eagle eyes! I was taking the caps off the P/S and was going to rely on the orientation per the service manual. If it wasn't that I came to this thread today and looked at dlucy's restoration, I would've installed the 47uF cap C602 incorrectly! Thank you to both of you!
 
jpreza said:
Thank you to both of you!
Click to expand...
Gotta mark caps before they are removed and install new same as old coming out, if the unit was working. Manuals and board labels can be wrong. Someone mentioned they put a sharpie mark on the side of the cap toward the front of the unit. Easy enough to pull a cap so marked orient it properly and know how it was installed in the unit before removal.

Glad ak saved another one.
 
jpreza said:
I was taking the caps off the P/S and was going to rely on the orientation per the service manual.
Click to expand...
Quite often the service manuals are wrong and if your memory is anything like mine, (which isn't as good as it used to be) it's out with the camera for lots of before and after pictures. Clear photos don't lie, especially if it's been a year or two since the work on the board was started.
IMGP0034.JPGPXL_20250611_180841744.jpg
 
Hello! Lurker and first-time poster here, and I wanted to just chime in that I'm doing a modest restoration on my 330c. I got this used in the mid-late 90s for $30. It was my first decent receiver I had and I loved the looks of it. Used it for a decade and it went into storage when I changed gear.
Pulled it out of storage a few years ago and the tuner didn't work and the signal meter was shot. Failed to get it working and now I'm back at it a few years later. Good news is I tracked down the tuner issue to a bad diode (D4 and D5, IIRC) in the B4+ section, and in the process, rebuilt a majority of the PS.
The old meter was completely shot but I was able to rehouse the guts from this into the original shell:

Moderator edit: link to eBay auction removed as that breaks AK rules.

It seems like others have had issues with this meter, so I can post whether it's a success or not.
Mostly I wanted to say thanks. This forum has has invaluable info and it's great to see other folks out there putting in the work to keep these old pieces running.
-Chris
 
Last edited by a moderator:
If it is a success, post manufacturer, model number...anything you can to help others search for it since the auction link had to be removed.
 
My very first post violated terms of service, sorry! Anyway, if you search an auction site for 40x40mm SD-306 you should see it. I did this a few years ago so my memory is foggy but I think it was a simple matter of replacing the white indicator behind the needle with the original HK one. I was going to glue it in, but the HK indicator plate had tiny holes on the bottom edge so I was able to use 1.4x4 metric blots to hold it in. I could just drill thru the plastic on the replacement meter. I wired it up and it works, that is, I can tune to a station and the needle swings like it should. I messed with the tension a bit to where it looked ok. This isn't a critical indicator to me, more just a cool thing to look at.

This receiver probably needs a tuner alignment, but I'm going to use it for a while as-is before figuring out how to take that on.

-Chris
 
Tried to replace the transistors on the phono board to KSC1845FTA by Onsemi. Now the riaa is practically dead, when playing a record it sounds like there is no riaa at all?
Did I solder them the wrong way perhaps?
riaa.jpgonsemi.jpg
 
Look at the schmatic and beep it out to see if you have to correct orientation. For example, the base of Q101 should beep to both a 100k resistor and the collector of Q103.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom