Klipsch pro media 2.1 system - he no workee. man cries.

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peskywinnets

Member
2010-03-31 2:04 pm
United Kingdom
  • #1
    So I've acquired some Klipsch pro media 2.1 which are apparently not working (nothing heard out of any of the 2 speakers or subwoofer) ....whipped the backplate off - nothing scorched inside (always a plus), so now want to start troubleshooting.

    I'm figuring here that since there's neither speaker working nor the sub, that it's likely a power supply fault or a preamplifier fault.

    Here's the whole list of internal module schematics...

    New Version Klipsch Promedia V2.1 Amplifier Repair

    & here's the actual power supply (click to enlarge)...

    2-1_power_supply_schematic-986x707.gif


    Explanatory words of the wise here...

    "The AC mains voltage passes through a small line filter and is then rectified to give approximately 340 Vdc for primary-high. Leaving off J9 configures BR1 for bridge rectification when the AC mains are 240Vac; stuffing J9 makes the bridge act as a voltage doubler when the AC mains are 120Vac, and gives the same approximately340Vdc. Primary-high is stored on a pair of series 200V electrolytic caps.

    Resistor R7 and D1 deliver the initial voltage from primary-high to turn on the controller, U1, living on a daughterboard. Transistor Q2 and ZD2 form a discrete regulator to power the controller IC. Diode D4 prevents backwards current from flowing into the regulator. Once power is applied, U1 generates a 50% clock set by R21 and C28. Each clock state generates a high pulse on HO or LO, the isolated gate driver outputs, with a fixed deadtime inserted between pulses. This simply alternates turning on the two half-bridge transistors. Diode D8 and C22 form a bootstrap circuit to turn on the upper FET, recharging the cap when the lower FET is on.

    The switched-mode power supply (SMPS) on the main SMPS board is a simple half-bridge, resonant, unregulated circuit. Each gate drive output goes through a gate resistor with ananti-parallel diode. The FETs, Q5 and Q7, alternately turn on, chargeing and dischargeing the transformer primary winding, T1:1. The resonant action of the supply is created because the current through the transformer primary must flow through either C3 or C5. This creates a square voltage waveform across the transformer primary with a sinusoidal current. This supply is very efficient as it uses zero current switching to (nearly) completely avoid switching losses. It's also excellent for audio applications because the lack of regulation isn't a detriment in the face of the high crest factor of audio signals. Finally, the square voltage waveform provides consistent, reliable output voltage.

    During normal operation, T1:2 also gives a square voltage waveform which is rectified by D3 to supply the controller with operating voltage, relieving R7 of this duty.

    Each secondary winding (T1:3 and T1:4) uses dual series rectifier diodes to bridge rectify the winding's voltage waveforms into a stable DC voltage. A small inductor filter reduces noise"
    Click to expand...



    I'm figuring the CN2 connector voltages (+39V & -39V) & CN3 connector voltages (+27V & -27V) are the first port of call for troubleshooting? (just got to rig this up to 110V AC....cos I'm located in the UK & our wiggly volts are bigger than your wiggly volts)

    (don't be alarmed...I do realise there's some chunky DC voltage (300V+ on C2+ to ground) on that SMPS so I'll proceed carefully!
     
    Last edited:
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    peskywinnets

    Member
    2010-03-31 2:04 pm
    United Kingdom
  • #2
    Well after all that, it was just a fuse! (albeit a fuse that didn't look like a fuse .....& a 'leaded' fuse soldered thru hole to the darned pcb).

    Looks like the previous owner has plugged a 110V device into 240V ...erhmm, pop.

    So I simply applied 110V to teh PSU input after the blown fuse (via a step down transformer mains lead that was in itself fused) & the unit sprang into life.

    Bit of a result ...picked this thing up quite cheaply.
     
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    pfitzgerald2

    Member
    2012-07-24 3:32 am
    Baltimore, MD
  • #3
    Klipsch Promedia 2.1 to 3-channel mod

    Very nice. Tinkering with one of these systems is what got me into DIY audio junk. If you have a need for bass and a subwoofer output on your music source (I presume it is a PC), you may want to turn your 2.1 channel setup into a 3.0 setup.

    Right now, a low-pass filter in the control pod is separating tones of <80 hz and directing them to the subwoofer amp. You can circumvent this filter and feed the subwoofer amp directly from the sub out port on a sound card. Creating the low tones for the sub with software, instead of circuitry, gives you much more control over crossover frequency and thumpiness.

    I've got mine relayed through a toggle switch so that I can switch between the 3.0 and the 2.1 methods. If you were able to find and replace that fuse, you'll have no problem with this. Let me know if you're interested, I can post some pictures for you this weekend.
     
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    paulod

    Member
    2013-09-27 2:06 pm
  • #4
    peskywinnets said:
    Well after all that, it was just a fuse! (albeit a fuse that didn't look like a fuse .....& a 'leaded' fuse soldered thru hole to the darned pcb).

    Looks like the previous owner has plugged a 110V device into 240V ...erhmm, pop.

    So I simply applied 110V to teh PSU input after the blown fuse (via a step down transformer mains lead that was in itself fused) & the unit sprang into life.

    Bit of a result ...picked this thing up quite cheaply.
    Click to expand...


    Hope you don't mind me bumping this thread.

    I am over in the UK also and got the pro media from the US which was plugged into the 240 and "POP" :-(

    I took out the PSU and can see firstly that the T2A/L250V Fuze is open.
    Also one of the Caps may be gone (top is a bit bubbled).

    I tested all the diodes and regulator BR1 and they all look ok.
    I'm hoping that just these 2 components were damaged.
    I see there is a link on the board called J9 and it says "Remove to r240v".
    Has this anything to do with converting the PSU to a 240 input.

    Anyway if I get a 240 to 110 stepdown converter at the same A rating should this be ok?

    Many thanks for the advice.
     
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    Andyemm

    Member
    2015-06-24 3:25 pm
  • #10
    fa8d4e31_game-of-thrones-arise.xxxlarge.gif


    Hi all, like my friend in the picture I'm new in town and here to bring things back from the dead.

    I'm got a set of Pro-media 2.1 (presumed) 110v's in the UK and was wondering if anyone had a photo of J9's location? I'm not wildly fluent in electrical diagrams but this seems like a good job to start learning. Please point out if that's not the case!

    TIA
     
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    VinDiesel

    Member
    2015-04-28 11:32 am
  • #11
    Andyemm said:
    fa8d4e31_game-of-thrones-arise.xxxlarge.gif


    Hi all, like my friend in the picture I'm new in town and here to bring things back from the dead.

    I'm got a set of Pro-media 2.1 (presumed) 110v's in the UK and was wondering if anyone had a photo of J9's location? I'm not wildly fluent in electrical diagrams but this seems like a good job to start learning. Please point out if that's not the case!

    TIA
    Click to expand...
    hi andyman just wonder what is the name of that movie in vid.. excuse me if it's no in topic of the thread
     
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    Andyemm

    Member
    2015-06-24 3:25 pm
  • #13
    So to answer my own question:

    hh4eXMQ.jpg


    That's after I removed it the hardest thing was getting the panel out of the sub which took quite a lot of levering. Then I took the board in the picture off the main plate and de-soldered what seems similar to a staple. After attaching this (which was a perfect fit) http://www.amazon.co.uk/gp/product/B00MPJBXZA?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00 to the plug it was all systems go!

    I realise this isn't much new information to most of the people on here but hopefully it will be useful to a fellow daunted newbie. I got a set of Promedia landed from the US for £60, even allowing for the cost of the plug it's still less than half price on Amazon.
     
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    Cyry88

    Member
    2016-07-17 6:09 pm
  • #14
    Man I just registered to leave a message to thank you immensely for the tip!

    I ordered my set from the US and plugged it straight in, needless to say the green light didn't illuminate for long!

    I followed your tip about removing the J9 jumper and it's working fine on 220v, man this set is loud!!!


    I really want to write an angry email to Klipsch though, why the hell wouldn't they include a 2-pos switch to select 110 or 220? It seems ridiculous not to have included one or even a dual PS like most laptop PS bricks... Well at least there's actually a possibility to use it on 220v, as technical as that solution is...

    Anyway, thank you so much to you all! :)
     
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