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Recapping and restoring a Harman Kardon 330C

The person who bought my newly-restored 330C shared that he mainly played vinyl, so I completely rebuilt the phono stage before sending it out. These are the additions to the above BOM if you're going to rebuild the phono (EQ) board and not just recap it and replace the small signal transistors:

EQ amp R101,R102 2 Resistor Carbon 68 K Vishay 71-CMF6068K000FHBF
EQ amp R103,R104,R125,R126 4 Resistor Carbon 330 Vishay 594-SFR16S0003300JA5
EQ amp R105,R106,R127,R128 4 Resistor Carbon 220 K Vishay 594-SFR16S0002203FR5
EQ amp R109,R110 2 Resistor Carbon 100 K RIAA Vishay 594-5053HD100K0F
EQ amp R111,R112 2 Resistor Carbon 330 K RIAA Vishay 594-5043ED330K0F
EQ amp R113,R114 2 Resistor Carbon 390 RIAA Vishay 594-SFR16S0003900FR5
EQ amp R115,R116 2 Resistor Carbon 220 Vishay 594-SFR25H0002200JR5
EQ amp R117,R118 2 Resistor Carbon 10 K RIAA Vishay 594-5053HD10K00F
EQ amp R119,R120 2 Resistor Carbon 22 K RIAA Vishay 594-SFR2500002202FR5
EQ amp R121,R122 2 Resistor Carbon 390 K RIAA Vishay 71-CMF55390K1%T1
EQ amp R123,R124 2 Resistor Carbon 2.2 K Vishay 594-5053HD2K200F
EQ amp C103,C104,C107,C108 4 Capacitor Ceramic 82 pF Murata 81-RDE5C2A820J0P1H3B
EQ amp C117,C118 2 Capacitor Ceramic 0.012 uF Murata 81-RCE5C1H123J1K1H3B
EQ amp C115,C116 2 Capacitor Ceramic 3300 pF TDK 810-FK24C0G2A332J​

or in cut-and-paste form:

71-CMF6068K000FHBF 2
594-SFR16S0003300JA5 4
594-SFR16S0002203FR5 4
594-5053HD100K0F 2
594-5043ED330K0F 2
594-SFR16S0003900FR5 2
594-SFR25H0002200JR5 2
594-5053HD10K00F 2
594-SFR2500002202FR5 2
71-CMF55390K1%T1 2
594-5053HD2K200F 2
81-RDE5C2A820J0P1H3B 4
81-RCE5C1H123J1K1H3B 2
810-FK24C0G2A332J 2​
 
Ulysse said:
Doug, this is a great post!
Do you have a similar list for HK930? I am trying to recap at least the power supply section. Thanks!
Click to expand...

Thanks, Ulysse!

I do not have a list for the 930 as I've never restored one. I've done a bunch of HK 330A, 330B, 330C and one Three Thirty so far. Doing a list without the unit isn't hard, but it does take some time.

There are two Sansui solid state 7000's sitting on my bench that I'm working on now. I've got to get through them before I do anything else. Check back with me in a month and you might talk me into making you a starting-point list.

Cheers!
 
dlucy said:
Power supply D1 1 S4VB20 200 V (4A) 583-BR62
Click to expand...

Hi dlucy,

Nice work and thank you for cross references!

I've got a 730 using S4VB20 bridges and wondered if the 583-BR62 could be used in this unit also. Seems like the bridges from mouser in 4 amp like the original are different configs and you have to get to 6amp like your cross to have square body.

Thanks,

Mark K.
 
Hey Doug,

Your cross lists are really helpful and I know you put some time into it, so thank you again. I will update when I get them in.

Mark K.
 
If you are diagnosing or recapping or rebuilding the power supply in your 330C, read the following from @Blue Shadow carefully. It is important.

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.
Click to expand...

It took me a few months before I realized how important the above quote is when rebuilding. Make sure you don't miss @Blue Shadow 's advice.
 
I have a comment and a question:

I would use the audio grade capacitors in the signal path and regular electrolytics in the power supply section.

Can you tell me what criteria you used when picking the resistors for the phono section?

Thanks in advance.

Best

Soundork
 
Soundork said:
I would use the audio grade capacitors in the signal path and regular electrolytics in the power supply section.

Can you tell me what criteria you used when picking the resistors for the phono section?
Click to expand...

In the audio path, you want the caps with the lowest DC leakage. So, polyester or polypropylene film caps where possible and low leakage electrolytic (like a Nichicon KL series) where film caps are too small (too low a capacitance).

In the power path you want electrolytics with low ESR (less resistance means less power wasted as heat) and highest ripple (mostly important just in filtering caps in the power supply).

For resistors in the audio path, metal film has less noise (?) and precision (1%) metal film resistors are cheap.

Keep in mind I'm just a hobbyist. There are pros and E.E.'s and old timers here on AK with far more knowledge and experience than me.
 
Doug, maybe you can help me with your experience with HK.

The HK930 I got has issues. Originally, the power fuse was blown, and I was able to find a short in bridge rectifier and replaced it. It turned on and played well for about 20 minutes, but then one of the speaker fuse blew. I measured the DC offset, and got readings 130mv for the blown channel and 70mv for the other. So not very healthy. I'm now running it through a dim bulb, and the receiver is not stable. Sometimes I could turn it on and ran for an hour without issue, but sometimes as soon as I turned it on, the dim bulb lighted on, suggesting a short somewhere. If I disengage the speakers, the unit runs well with no issue. So I guess the pre-amp section works well.

Someone suggested it could be runaway bias issue, and I should replace the varistors (two pairs of diodes), but there could be other issues. So I am going to try to recap the power supply and driver board, replace those diodes. Any other things I should consider here? Input differential pairs? Output transistors? Want to order all the parts together and fix them all at once...

I plan to replace capacitors for the driver board with Panasonic FC series, and the ELNA LAO for the big filter caps. These should work OK, right?

Thanks!



dlucy said:
Thanks, Ulysse!

I do not have a list for the 930 as I've never restored one. I've done a bunch of HK 330A, 330B, 330C and one Three Thirty so far. Doing a list without the unit isn't hard, but it does take some time.

There are two Sansui solid state 7000's sitting on my bench that I'm working on now. I've got to get through them before I do anything else. Check back with me in a month and you might talk me into making you a starting-point list.

Cheers!
Click to expand...
 
dlucy said:
Keep in mind I'm just a hobbyist. There are pros and E.E.'s and old timers here on AK with far more knowledge and experience than me.
Click to expand...

I think that you are too modest. You are beyond the hobbyist part now.

I have couple of follow up questions: Were you able to detect any differences in performance after the phono section was updated? Also, did you update it incrementally i.e. first the caps, have a listen, then the resistors, have a listen...etc., or you did everything at once? If the former, I'd like to know if you were able to discern the changes to the sound due to the type of component change.

Thanks in advance.

Best

Soundork
 
Soundork said:
I have couple of follow up questions: Were you able to detect any differences in performance after the phono section was updated? Also, did you update it incrementally i.e. first the caps, have a listen, then the resistors, have a listen...etc., or you did everything at once? If the former, I'd like to know if you were able to discern the changes to the sound due to the type of component change.
Click to expand...

My ears are not high performance models, so I can't say "it's sounds a million times better and especially in the (insert favorite driver here) range." I've got to be honest in answering a question like this. I _feel_ like the performance is better, but I didn't do an A/B test as I only have the one unit and initial performance, tear down and rebuild, and subsequent performance were weeks apart.

The end result sounds excellent, to my aging ears. Initial performance was ok, but not excellent. That's as precise and empirical as I can offer.

Oh, and it was a ton of fun doing the working and admiring he result.
 
Ulysse said:
Someone suggested it could be runaway bias issue, and I should replace the varistors (two pairs of diodes), but there could be other issues. So I am going to try to recap the power supply and driver board, replace those diodes. Any other things I should consider here? Input differential pairs? Output transistors? Want to order all the parts together and fix them all at once...

I plan to replace capacitors for the driver board with Panasonic FC series, and the ELNA LAO for the big filter caps. These should work OK, right?

Thanks!
Click to expand...

So, you have a dilemma: the smart thing to do is go step by step: measure, diagnose, replace a component, then repeat, but the shipping charges for more than one order from a Mouser or a Digikey will quickly exceed the cost of the parts in an everything-shotgunned-at-once approach. You'll need to decide which way to go, piecemeal or shotgun, at least in terms of ordering. If you're rich (not me) or crazy (me), then there's no dilemma.

My recommendation, what I would do, is 1) order all the parts to shotgun in one order, then 2) take a careful step by step approach as you diagnose and replace. You may buy a few too many parts or end up making a second order due to a mistake, but you'll avoid slow high cost of many little orders this way.

Regardless of how you order, I would suggest getting the following parts:

Caps to replace all Electrolytic caps everywhere.
All of the components on the power supply board.
All of the components on the power amp board.
All small signal transistors that show up on the "noisy transistors" list.

Then I would do the following:

100% rebuild the power supply board and then verify its outputs are correct.
100% rebuild the power amp board.
Replace all electrolytics everywhere. Where possible and between boards replace the coupling electrolytic caps with metalized polyester film caps.

That's a shotgun, OCD, or Doug-has-no-life-and-likes-replacing-stuff approach.

A more measured approach would be:

Check all power supply voltages coming off the power supply board. If all good, wait til later to rebuild. If any are off, go ahead and rebuild the power supply.

Check the emitter resistors and trimpots on the power amp board. Replace if not perfect. Heck, replace them anyway.

Old trimpots are notorious for causing issues.

Check each transistor in the power amp board with a transistor tester. If any are bad, replace them in channel pairs.

If you have varistors, not all amp boards do, but if you do have them you can try replacing them with doubled-up diodes. There is a great article on how to replace STV-3 and STV-4 varistors that'll help get you there, if needed. If yours aren't bad, then leave them in place.

Now you should be in the zone. The big issues should be fixed. Now you _should_ be able to do clean up work like replacing all the rest of the electrolytics and the known-noisy small Signal transistors.

The preamp board will sound better with renewed caps and maybe some transistors. But nothing on the preamp or tone control boards should be causing big output problems like you're stating. So, you can save these boards til the end.

If you listen to a lot of vinyl and you use the PHONO channel in your HK, you may want to order all-new replacements for the resistors and ceramic caps in your phono board. New 1% metal film resistors should lower the noise floor and modern MLCC (multi layer ceramic caps) with C0G NP0 dielectric insides will be far closer to the factory specs than the aging and less-precise original parts. The transistors on the phono board should be candidates for replacement, the KSC1845F is a common, cheap, low noise device for these, but check each original transistor for the right replacement device and pinout. And it'll only like $11 in parts to rebuild the whole board.

So, there is a bunch of partly-right advice. And you should see some other, wiser folks commenting and pointing out where I've gone wrong. But you've got a starting point.

And be sure to start a new thread for your rebuild. Everyone here will chime in and help and it'll be fun.
 
Last edited:
Doug, wow, I didn't expect such a detailed write-up! Thank you so much!
But, I have to say you ARE crazy, lol! I just want to fix the receiver, not rebuild it. Just don't have that much time right now. And as a novice, I don't want to break things to cause bigger issues. The inside design of 930 looks like spaghetti to me. Wires are running like crazy...

I already started a thread, and fixed the first issue in the bridge diode.
http://www.audiokarma.org/forums/index.php?threads/harman-kardon-930-short-out-need-help.805341/

I tested power supply voltage, and it seems OK at around 36-37V, so I will leave that part alone for now.
I'll follow your advice to check the resistors and transistors on the driver board, and then the varistors.

This is a much bigger effort than I thought when I picked up this thing for $30...
 
Ulysse said:
Doug, wow, I didn't expect such a detailed write-up! Thank you so much!
But, I have to say you ARE crazy, lol! I just want to fix the receiver, not rebuild it. Just don't have that much time right now.
Click to expand...

Yep, I totally understand.

Verify the voltages coming out of the power supply are all really close to the specs. The power supply is where the basis for everything else starts.

Then check the resistors immediately around the final two layers of transistors on the power amp boards. Verify they are not shorted and are close to schematic values.

Then check the output transistors and the two layers of transistors leading up to those big output transistors.

Then check the trimpots, the variable resistors, near the output transistors.

And check those varistors.

Good luck!
 
dlucy said:
Hey Mark,

You're asking a great question. The parameters for S4VB20 (200V 4A) and 583-BR62 (200V 6A) are the same (or better) and the leads are the same layout and dimensions.

http://pdf.datasheetcatalog.com/datasheet/Shindengen/mXqwqtu.pdf

https://www.mouser.com/ds/2/345/br605-610-16886.pdf

I think your use of the 583-BR62 will fit and work fine in lieu of the S4VB20 in your HK 730.

Good luck and let us know how it goes!

Doug
Click to expand...

Hi Doug,

I installed the bridges yesterday along with some new filter caps and everything seems to be working well.

Thank you again,

Mark K.
 
markuus3889 said:
Hi Doug,

I installed the bridges yesterday along with some new filter caps and everything seems to be working well.

Thank you again,

Mark K.
Click to expand...

Great news!

I recommend you post what your original issue was and what you did to fix it in a new thread. That way people searching for a similar fix in the future will find your work and benefit from it.
 
I had no real issues with the 730 just doing a refresh and some upgrades/modifications. This is a receiver my grandfather bought new when they were on the shelf. It does sound wonderful. After running for hours the transformers are room temperature and the heatsink is barely warm driving Infinity RS5000's for testing.

Mark K.
 
dlucy said:
My ears are not high performance models,
Click to expand...

Do you think it might be that fancy astronaut helmet you are wearing? Give em a listen without the lid and I think you will hear better.

Can you tell us why the a844 and c1344 get replaced with the same transistor, the 1845? The first two are different types, pnp/npn and you have a pair of npns going in.


Doug, this thread keeps getting better.
 
Blue Shadow said:
Do you think it might be that fancy astronaut helmet you are wearing? Give em a listen without the lid and I think you will hear better.
Click to expand...

Hah! The Russia space program test pilot's helmet may well be my problem!
 
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