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JohnW

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    Help--Need a Harman Kardon 430 tech.

    in 2-Channel Home Audio

    Posted

    10 minutes ago, captainbeefheart said:

     

    Move on to that transistor bolted to the heatsink right next to the bridge rectifier. Use a diode tester and check the transistor base-emitter and collector-base. Check it for shorts also.

    Any tips on how to "check the transistor base-emitter and collector-base?" I have no idea what that means. 

    Help--Need a Harman Kardon 430 tech.

    in 2-Channel Home Audio

    Posted

    34 minutes ago, captainbeefheart said:

     

    EDIT:  I found where it is and what it does.  It's 8.2 ohms 1/2 watt

     

    It is in series after the fuse from the transformer to the bridge rectifier D6 on "rectifier board A". 

     

    Check the bridge rectifier D6 and also check the regulator transistor Q1 for shorts. Also check D7 the reference zener diode and all the capacitors around Q1.

    Thank you, will do. I checked everything on Rectifier Board A last night for shorts, and they were all good. But obviously they weren't shorted, because current is obviously passing through them.

    I'm a novice at this sort of thing. Appreciate the help.

    • Like 1

    Help--Need a Harman Kardon 430 tech.

    in 2-Channel Home Audio

    Posted

    11 hours ago, Davecv41 said:

    The fuse was blown, it got replaced with a larger current fuse, then the over current turned R9 into the weakest link in the circuit. It sounds like you have a short circuit, and you need to find it, otherwise you can keep replacing the fuse and the resistor until the cows come home, and still have no music.

    Yes Dave, I know that. Can anyone identify the resistor? Is that 8.5 watts?

    Help--Need a Harman Kardon 430 tech.

    in 2-Channel Home Audio

    Posted

    So I bought this receiver for $200, and it was DOA. Seller assured me it worked when he sent it and I believed him. So I removed the top and bottom covers and found all the fuses.

    One of them, FU1 (from the wiring diagram) a .5A fuse, was nonconductive. Aha! I didn't have a .5A fuse, but I did have a 1A fuse. Popped it in, and it worked!

    And then the resistor (R9) connected to the fuse started smoking. And then the the sound cut out again.

    Yes, I feel like a bit of a dumbass.

    .5A fuses have been ordered. And I'd love to buy a replacement resistor, but I cannot, for the life of me, identify what it is. I found it on the wiring diagram in the 430 service manual, but it's pretty much unreadable (see attached screen cap). I can't locate the resistor in the parts list nor in the schematics. But I am not terribly experienced readin schematics.

    Could someone please identify the resistor so I can get one, install it, and pick up where I left off? Thanks in advance.

     

    Resistor.PNG

    Receiver as preamp for SET tube amp?

    in Talkin' Tubes

    Posted

    On 2/7/2022 at 8:13 AM, KASTLROCK said:

    I'm needing to do the exact same thing as you have did, what is the bypass switch you are using?

    I have a marantz sr5015, vta st-120 tube amp, and klipsch belle's, having simple bypass switch would be perfect! Essentially I have to share the belle's with my wife/kids/tv, but I hate unplugging things when I want to run the tube amp. 

    This is exactly what I use: https://www.ebay.com/itm/SPECIALTY-AV-2-Amplifiers-Receivers-to-1-Pair-Speakers-Selector-Switch-Combiner-/224545913401?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=711-127632-2357-0

    Went heritage speaker shopping yesterday . . .

    in 2-Channel Home Audio

    Posted

    I can't speak to the modern versions of the LS and the CWIV...but having just switched from a pair of '85 Cornwalls to a pair of '85 La Scalas, I can attest to the difference in bass. I had high expectations, and I have to say, I was not blown away.

    Don't get me wrong--they sound amazing...more detail than the CWs, tighter bass (but not as deep). What this makes me realize, is just how special the CWs really are, that they're not that different from the La Scalas in quality--and this is the conclusion that seems to be drawn between their contemporary iterations as well: You trade maybe 10% in detail for a lower octave or two of bass.

     

    • Like 2

    Which finish on my unfinished La Scalas?

    in 2-Channel Home Audio

    Posted

    4 minutes ago, Khornukopia said:

    Probably should stain or dye them before the finish coat. Birch reacts to stain differently than other woods, so I would gather an assortment of tints, turn one speaker over bottom up, pencil mark a grid, stir and dab a bunch of samples and clearly label the grid. Let that dry and then apply some Boiled Linseed Oil. Then ask your wife to help you pick one.

    Way ahead of you. bought a nice 2'x4' piece of birch plywood and a few different finishes last weekend. I'll start tomorrow. Currently leaning toward amber shellac, or possibly multiple coats of Danish Oil.  Staining isn't out of the question, but doing it well on baltic birch is a multi-step process, and I'm not entirely partial to a nice stain job with exposed plywood edges. 

    There's some figuring in the speaker wood...and I'm tempted to dye it to bring that out and then seal with poly or acrylic. But that's a bit risky...I don't have any real wood finishing experience.


    I keep going back to this video:


     

    • Like 2

    Turning an AL into an AA or an AL-3 or..

    in Technical/Restorations

    Posted

    On 11/5/2018 at 4:06 PM, slk23 said:

    I have a pair of 1985 La Scala's (industrial style) with AL crossovers (no zener diodes) that I suspect could use a refresh.  Are there more reports on the "wdecho mod"?  Would that mod work well for high volume listening?

     

    Also, while I don't mind adding the zeners I wonder how important they are; my speakers were driven at max. levels with a Hafler 250 watt/channel amp for hours at a time back in the '80s.  I blew a few fuses on the speakers but never lost a tweeter.

     

    TIA.

    I'm in exactly the same position. '85s with ALs. need a recap. Don't need to buy 20 caps.

     

    Which finish on my unfinished La Scalas?

    in 2-Channel Home Audio

    Posted

    31 minutes ago, 001 said:

    @HDBRbuilder is the Pro on the Klipsch Forum ,  he used to recommend  1  application every 2  days  for 6 days  ,  once a month for 6 months   ,  then once a year for upkeep   , Linseed oil  does not leave  residues or chemical buildup , the oil penetrates the veneer and protects the wood -

     

     

    I think I read that after I got my Cornwalls. I did the boiled linseed oil with them, but they're the Oiled Walnut finish. Once a year I use Watco on them now.

     

    • Like 1

    lascala vs. cornwall

    in General Klipsch Info

    Posted

    Hm.

    Just bought a pair of '85 La Scalas (AL crossover, K-77/K-55M) to replace my recapped (Crites) '85 Cornwalls. Not unhappy with the Cornwalls, just thought I was upgrading.

    Not an upgrade, apparently. Just different. a little more detail in the mids and highs, and the lack of bass is well, apparent. Same sub I was using with my Cornwalls. I just switched out the two fronts and re-ran room correction. Played around with toe-in.

    I don't mind the sound difference. What I was hoping for was more presence and imaging...thought it would sound more like I was in the same room with the performers. But the soundstage with the La Scalas make them sound a bit further away. Not much...but I was hoping the imaging would bring them in another direction, ie, closer.

    But I just made the switch. I'll give it time. A recap may be in order, but not for ALs. I'll either convert them to AAs or AL3s...could use some guidance on that--what works best with the K77/K55M combo. I'm certainly not lacking in high end at the moment.

    High quality problem, right?

    • Like 1
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