Todd Davis

Hi friends -- My apologies for not following up with you earlier. I think it was dbert or tc3sean that noticed the blistering capacitors and changed the amp/pre-amp chip. Yes, those electrolytic caps are a problem on these units I've replaced the same two and from my experience, those are likely the only two. If you can get your hands on an ESR meter you can read the remaining electrolytics and replace as needed. The loss of the audio now from the sub I predict it was from replacing the IC. I haven't looked lately, but if that's the small surface mount ic on the dock, that's a tricky bugger to remove. You have to be really careful not to damage or lift the traces. Clean the pads with a flux cleaner and tin (apply a light amount of solder to the) pads before soldering in the replacement ic. Obviously an oscilloscope would be the best tool to trace the signal to find where it's getting lost. Another really cheap audio probe is a paper clip or metal jeweler's screwdriver. You'll notice a 60hz hum when you tough the metal to the circuit traces. Find the input pins to the power amp IC and work your way back to the dock and then back to the sub where the audio line comes in. BE SURE THAT IF YOU DO THIS YOU DO NOT GO POKING AROUND THE 110V AC areas. That should be obvious but... Best of luck -- keep posting!

dbert -- thanks for the kind words and additional information on the MC86Hcrlk38%#82148$8* IC. Well, that's a surprise of sorts. I just took my dock apart and yep, that's a scary thing to see. That's basically a PLA, similar to a custom microprocessor circuit. Very complex internally -- which when compared to drivers and other high current devices, tends to rank among the more likely components to fail. I had my unit unplugged for a day and when I powered it back up it worked somewhat reliably. That steers me more towards this type of circuit as a likely failure tho that's not to rule anything out completely elsewhere. Temperatures influencing a breakdown in a component. I guess for the moment, I have to go back to my request a few days ago -- where's a schematic and oscilloscope? I'd think that if I can get my hands on a print I can sort this out. Unless one of the fine folks at Klipsch might want to weigh-in on this... Like I said the other day, most people would prefer to fork out the $57 to replace the dock if they know within a reasonable degree of certainty the replacement docks have resolved the problem. Or, just help the tinkerers of the world who will figure this out anyway, and just do the right thing by letting us know what the bottom line is about the docks. Keep me posted -- and thanks again for everything. Todd

Hi dbert - Thanks for the comments and follow up. Well, a few to add, process of elimination and avoiding the grimbly. I received a response from Klipsch today re. volume issues. Their response to my request for service info. etc: "purchase a new dock" for $57. Provided they suggests takes care of the problem, then for the moment we can presume the problem is in the cable to the dock. (And reading your comments, I'd say, toss the IC into the suspect pool. Often in my service days, we'd see a bad batch of chips come down the pike that would mess a lot of things up. However, high power, high heat, high demand ICs fail 100:1 to simple, low-power ICs.) It still may be noise in the power, grounds or from the volume switch, or pot. (I'll look it up eventually). That's to say, because the circuit is essentially idle until input is sent to it, low/noisy power, and/or faulty grounds may only have an effect once the chip begins to function. This could be determined easily with a schematic and oscilloscope -- which I have neither in front of me at the moment. As a former service center owner, I would routinely contact companies, such as Klipsch, and order a schematic. These days with the Web, more of that's done online with PDF-types of diagrams. I haven't seen any out there as of yet. Perhaps if someone knows of a service center who has the diagram or would be willing to order one, they could let someone know. If anyone is reading this at Klipsch, no bad feelings, I hope. I'd figure for most, it is easier to spend $57 to buy a replacement than spending an afternoon taking apart a dock and trying the do-it-yourself routine. I think, however, 1.) if people felt confident the replacement dock wouldn't fail prematurely like the original ones did, they'd just order it and go on their merry way, and 2.) for those of us who would prefer to mess with our own stuff, we'll find the cause/solution eventually -- with or without your support -- and then we'll blab it to others. So, a little honesty and help could be in order here. But what do I know, I only handle corporate communications for a Fortune 10 consumer products company. TD

hi there - new here, and yes, I have a iFi that is having the same problems with the iPod dock/volume. I think many have been asking the wrong questions here for some time. The issue is, what specifically is causing the problem and what can users do to rectify that problem. It's no benefit to speculate on whether or not Klipsh knows about it or has parts, or whether this part of that is the culprit, etc., in my opinion. A few things. On the volume controller chip specified above, I've worked (technical) in consumer electronics for many years and basically this is a three channel audio level controller that works by receiving serial data. I doubt this is the problem, and from what I've read, I doubt it's the volume switch (though I wouldn't rule that out at the moment). What I think is happening is there is some type of electrical noise that is getting introduced into the dock. Data is being sent from the volume switch and buttons on the doc, and either fed directly into the LM1973 controller (or into the main woofer unit, where it is returned as control data) to the LM1973 chip) to control the volume. If there is a weak ground along the cable, or weak/"noisy" connection in the serial data stream sent to the chip the resulting control/function could become erratic. (I've also noticed what sounds like dry capacitors in the main unit for some time as well, this causes a constant buzz in the audio and could also mean noise in the unit's power for the logic system. This could also create an erratic condition similar to a faulty or weak ground.) This is to say, "noise" in the cable connecting the dock to the main unit will disrupt the data in-between the two devices and lead to the problems many are experiencing. I'm willing to help, though I'm not working in the biz anymore, I've been there for years. If someone can get me a PDF of the schematic that would do wonders. I'll check back here periodically. (April 12, 2009). P.S. I'm new to blogs and all that fun stuff, so if there's a better place to provide input/assistance, please let me know. Best, Todd