Posted in audio, gear, HK, vintage

    I've owned maybe a dozen vintage receivers over the past several years, but this one remains my favorite (hence why I've kept it). I bought it on Kijiji for $80 a couple years ago and have since given it a thorough cleaning. I've also replaced all of the internal lamps as several were burned out.

    Made in 1975 and the little brother to the HK 730, it features a "twin powered" design, which means each audio channel has it's own individual power supply. Even though it's rated at only 25 watts RMS per channel, it has more than enough power to fill a room. I'm currently using it as the primary receiver for my turntable and to power my floor speakers—I'll write about those another time.

    Repairs

    Replacing the lamps behind the tuner dial was ridiculously easy. The hardest part was actually finding suitable replacements (more on that later). The lamps themselves are a fuse type, which don't require any soldering to replace; just remove the old ones and snap in the replacements. You just need to remove a few screws to gain access first.

    I also had to replace the tuner needle light, which you can kind of see in the blurry foreground in the above photo (I don't know why didn't I take a better photo while I had it all dismantled). You just have to pry up the two metal side flaps and lift the casing off. Once removed, snip the wires to the lamp and solder the new one in place.

    I ended up buying the lamps from this site, which was the only one I could find that had both the tuner dial fuse lamps and the tuner needle lamp in stock. The tuner dial lamps were part number L-11 (0.25" diameter, 1.25" long, rated 6V and 250mA), and the tuner needle lamp was part number L-5 (0.12" or 3mm diameter, rated 6V and 35mA). You can also buy the fuse lamps from Amazon.

    All better

    Looking basically good as new! The next bit of repairs I might eventually tackle is replacing all of the capacitors with modern equivalents. There is an ever so slight hiss noticible when listening with headphones, and new capacitors might clean that up a bit—or so I've been told—as the originals are probably quite dry after 35+ years! I just need to practice my soldering skills first.

    31 comments

    Robert POSTIGO

    Robert POSTIGO

    I had the same problem with the same receiver (HK 430)
    it was not easy to find these fuse type lamps in France
    i found them from e-bay from US (Tech Hi-Fi, Roseville, MI 48066)
    very easy to replace
    dial looking as new
    Robert from France

    abel

    abel

    Jeff
    Thanks for the write up. I just got a 730 last week, all cleaned up and sounds amazing. I have about 4 dial lamps out, dial needle lamp is out as is the power switch lamp. I will try the dial and needle lamps soon and research the power switch lamp later as it looks a lot more crowded down in that corner of the unit.

    Jason

    Jason

    Jeff,

    Many thanks for the excellent article.

    I have an HK430 that I've owned for probably 13 years now, connected to a pair of Klipsch Heresy IIs that I've had for 20 years, and a Sunfire Sub that I've had for probably 5 years. I use them to handle the 2-channel audio on my widescreen TV in the living room.

    They get a lot of use (12 hours a day) and the bulbs on the HK430 are now all burned-out. My question is, "How many bulbs does the unit take?"

    I'd rather ask and then order the required number of bulbs so I only have to disconnect everything and take the receiver apart only one time (it's the proverbial rat's nest of wires under the TV with all the gear interconnected).

    Thanks in advance!

    Jason

    Jeff

    Jeff

    Jason, I honestly don't remember how many fuse lamps it took. Looking at my photos, it looks like at least four, however I think there would at least one more possibly two. Plus the signal strength meter would be another of the same type.

    Luckily all of the lamps are cheap enough that you can order more than necessary, so you are guaranteed to have enough for the repair plus some spares in case you need them in the future.

    Jeff

    Jeff

    I checked the service manual again, and it shows there are six required. But it doesn't specify if it includes the signal strength meter. So I would get at least 7 to be safe.

    You can find the service manual here - http://hifiengine.com/library/harman-kardon/…

    Jason

    Jason

    Jeff,

    MANY thanks for the quick, helpful response!

    I will take your advice and order 7 of them, just to be safe.

    Kind regards,



    Jason

    Joe

    Joe

    I also have a 430 and noticed that the #1 power transformer runs warmer than the #2 power transformer. #1 Xmfr has the secondary supply for the display lamps which are rated for .25 amps (x6 lamps = 1.5 amps). Heat is a killer for most gear so I decided to remove the lamps. Now both xmfrs run about the same temp and the display has a nice cool look to it with only the lamp in the pointer being on. Another option is to use LED's. This will cost more but it will help preserve this wonderful sounding little receiver which I'm listening to right now. Sweet!!!

    Lynn

    Lynn

    I own one of these terrific receivers and would like to do two things that I need yr advice on please?
    1) What's the best antenna to boost the AM signal using the H/K 430?
    2) Want wireless speakers (so we can enjoy the sound anywhere in the house or outback)?
    I do understand that wireless speakers aren't going to give the quality audio one expects (or that you all may get from higher end speakers)...so forgive me for asking about a lesser speaker. Don't mean to offend all the audiophiles out there!
    Thanks for any advice you care to post.

    Jeff

    Jeff

    Apologies for the late reply.

    As for the AM reception, I would look into an external antenna. I am sure if you google for DIY AM Antenna, you will get lots of helpful responses.

    Regarding wireless speakers, I don't know any specific models unfortunately. I imagine you'll need to get a wireless receiver that accepts speaker wire input (from the HK). I don't know if one exists.

    I am guessing that any wireless speakers would need to be individually driven by built in amplifiers, meaning that none of the vintage goodness from the HK would even make it to your wireless speakers. You would effectively be sending the analog signal from your HK into a wireless receiver, where it's converted to digital, then beamed to the speakers, then converted back to analog by each speaker's built in DAC, then finally amplified using each speaker's built in amp. Any benefit in using the vintage HK would be destroyed.

    Ron

    Ron

    Jeff,

    Great site inspired me to fix the lights on my 430. I'm relatively new to this type of endeavor, but I ordered the parts got the fuse lamps in and amazingly removed the face and soldered in a new indicator lamp. However to get the face off I had to remove the tuning knob which required loosening the tuner string ... however this is where I'm now stuck. I unscrewed one of the white pulleys to create slack but I cannot seem to get it back in? What was your plan of attack? Did you re-string from scratch? Any guidance is appreciated.

    Jeff

    Jeff

    I find it strange that you had to touch the tuner string to remove the knob. In every receiver I've ever touched, the knob just pops off without issue and the HK430 was no exception. It sounds like maybe your unit was modded or something. Not sure.

    I've never done a tuner restring from scratch, but I have restrung the original a few times on other units. It's always a major pain in the ass. The service manual should have a restring diagram in it.

    http://hifiengine.com/library/harman-kardon/…

    Ron

    Ron

    Jeff

    In retrospect it appears I over complicated removing the face on mine. I was a bit gun shy with applying enough pressure to remove the external knob and ended up removing the entire assembly from the inside ... Not recommended. I just acquired a 730 that needs a similar overhaul and plan to take the simpler approach for sure. Thanks for the reply.

    Ron

    Audiophil

    Audiophil

    I just changed the bulbs on my friends 430 and then tried it with a pair of my Totem Mites. It sounds very similar to my same era NAD 3020, but sure looks a lot better! The 430 is very well built, IMO and these are worth saving.

    PYM

    PYM

    You can find the "fuse lamp" 6.3V 250mA at "E44" in Nantes (France), for about 1.2€ each.
    http://eclairage-lampes.e44.com/lampes-miniatures/…
    the indication 150mA is a mistake, it's some 250mA!!
    I restored my HK 430 this week (replaced all the chimical condensers, and all the lamp..

    bram

    bram

    hey, cool page....just bought a used HK430 and i'm super stoked...but got everything hooked up and noticed my speakers were crackling every time i changed the volume, after searching on google, most sites say that i probably have a "dirty pot" and an easy fix is turn the unit off and rotate the volume knob back and forth about twenty. i did as google suggested but now i believe i have made the problem worse.
    any thoughts?
    should i open her up and physically clean the pot?
    any advice would be greatly appreciated.

    Jeff

    Jeff

    Bram, you only did half of the job. You need to buy a spray can of plastics safe contact cleaner, and physically spray it inside the knob, accessing it from the inside. There should be a small opening in the back of the pot. Once sprayed, turn the knob back and forth a bunch of times. Repeat if necessary.

    bram

    bram

    hey Jeff, thanks for the reply...i think i prematurely left comment, should have read just a little more..
    I bought a can of deoxit and cleaned all my pots except the Function knob (FM/AM/PHOHO/AUX).... they work beautifully now.

    my new issue seems to be pretty sporadic, sometimes the left or the right speaker's sound seems to die out and get very tinny...i check the the rear speaker inputs and every thing seems to be fine there.....but when i just ever-so-slightly move the Function knob a tiny bit left or right, but not to the point of actually changing the mode, i get full beautiful sound.
    Does that mean i should clean that switch?
    and should i clean it the same way i clean the other pots?

    and is there any way to refurbish the top black metal? mine seems to have a little discoloration?

    thanks so much for your help!

    Jeff

    Jeff

    Yes, in addition to all of the pots you should also try to clean all of the switches, since they are susceptible to the same degradation over time. If moving the function knob fixes your problem, it sounds like it should be an easy fix.

    Aidan

    Aidan

    hey jeff. nice site. i have a comment for ron, on restringing the hk 430 (yes, i know it's an old post :) ).
    ron, reassemble your receiver, minus the dial string of course. now, set your pointer to midway on the dial. set the round molex (nylon?) disk attached to the front of the variable capacitor (those fins you see behind the dial pointer, about 1 1/2 inches behind it) so that the fins are at the half-way point between totally open and totally closed. start your dial restring at the inside point of that white disk on the front of the var capacitor. wind clockwise, only one revolution and when you get to the top of this one revolution, send the string off to your right, to the first small wheel, then in towards the front of the receiver to the second small wheel, then across to the pointer, to the front small wheel on your left, back to the inner small wheel on your left, and finally in towards the white disk, entering the disk in the groove in front of the groove you originally left it from, around one revolution clockwise, and tie off at that point. whew!
    hope this helps (or sufficiently confuses LOL)
    best,
    aidan

    Lynn

    Lynn

    Hey Jeff... I'm downsizing & selling my HK430. Do
    can you recommend a good site to post it?
    Everything works great. Kinda hate to part w/it.
    Lynn

    aidan

    aidan

    edit;
    "...then in towards the front of the receiver to the second small wheel,..." THEN TOWARDS YOUR LEFT AND DOWN SLIGHTLY TO THE TUNING SHAFT WINDING 3 TURNS COUNTER-CLOCKWISE WINDING FROM THE INNER PART OF THE SHAFT TOWARDS THE OUTER/FRONT OF RECEIVER,"...then (UP SLIGHTLY &) across to the pointer,...".
    Forgot that darn tuning shaft. :)

    Jeff

    Jeff

    Lynn, I sell all of my gear on Kijiji, which is like a Canadian craigslist. All depends what's available in your area. I avoid eBay because I hate dealing with shipping.

    Stephen

    Stephen

    Hi Jeff thanks for your site. I just got myself 430 and I'm doing the very same thing. Has anyone out there changed the power light? Mine is gone and it seems difficult to remove.

    I am planning to take out the blown lamps and to convert them into LEDs by simply soldering a small 3 mm LED and an in-line resistor across the fuse bulb. I will post a pic when I am done cheers

    Tyler

    Tyler

    What is the lamp type for the power switch and the stereo light?

    Stephen

    Stephen

    Hi

    I just replaced my lights with LEDs. It took a little more time than I expected since I was unaware the main bulb circuit is AC. I made little replica bulbs using plastic drinking straws and bicycle brake cable ferrules (both of which luckily I had lying around). Inside each of these I placed a 3mm warm white LED with an in-line resistor.

    Simply replacing them results in flicker due to the AC. It's not that obvious but I found it annoying. So I decided to rectify the AC circuit. This was pretty easy - 3 components, a bridge rectifier, smoothing cap and a 7805 regulator. You could probably even do without the regulator as the total current required by the new LEDs is so small (circa. .1A) that a 1000uF cap would probably smooth it fine.

    I measure about 4.5 v coming out of the regulator (the 6V AC after rectification is probably not enough to get it up to the stated 5V) - but that was fine as it helps the LEDs to be not too bright. I had to darken the tuning needle lED with a sharpie as it was noticeably brighter after the replacement but the rest look fine.

    Just to confuse matters the stereo indicator light is rectified (fed from rectifier A).

    As I was doing this I noticed that half the 6V feed to lighting circuit (the green wire) is wired to a orphan contact on the Rectifier A board and then just joined to another length of black wire before threading up to lights. A design change? Maybe they were planning to rectify that light circuit and then changed their mind because of the current draw? Anyway I too the opportunity to clean up the wiring a bit.

    Very pleased with the results and the box is much cooler now - so I do recommend it. The only tricky thing is working around the dial string with the soldering iron. I nearly burnt mine through !!

    If anyone wants more info or pictures I will post them.

    pier

    pier

    Hi Stephen, I would be grateful if u could publish your pics. Regards, Pier

    Stephen Devlin

    Stephen Devlin

    Here are some photos from LED project.

    https://plus.google.com/photos/…

    Stephen Devlin

    Stephen Devlin

    Sorry - some problems with sharing the Picasa album. Try this one...

    https://plus.google.com/photos/…

    Stephen Devlin

    Stephen Devlin

    Seems to be some kind of problem with links on this site. When I paste the website URL it loses the colon in the link. If you want to see the pictures click on the link above and then manually insert the colon after https. Sorry seems to be a bug with the software hosting this blog.

    Tyler

    Tyler

    I've ordered the dial tuner bulb off of eBay. The bulbs are 6v 35ma and .12 in diameter. Can I use the bulb for the stereo light? What about the power switch? The seller had them in packs of five, so I have extra.

    Tyler

    Tyler

    In response to my previous post, the same bulbs for the dial tuner were soldered in for the stereo lamp, and everything seems to be working. My last lamp is the power switch, and then everything will be working. eBay sells a 5 pack for $5 or something like that.

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