Dan East

For those of you looking for the actual R7000 repair, I get to that at the very bottom of this blog. No, the power cord was not the repair.

I am the proud owner of a KLH R7000 tuner / receiver. It is a 600 watt receiver with Dolby Digital / DTS / Dolby Pro Logic II surround sound decoding, and a plethora of video and audio inputs and outputs. It has composite, super and even component video inputs and outputs, to allow easy switching of various video sources without having to resort to an A/B switch.

The reason I’m a proud owner of this receiver isn’t because I am in possession of this low-end, budget piece of hardware. It’s because it didn’t cost me a cent. Well, actually, it cost me $1.95, but I’ll get to that later. This receiver gets good reviews – when it works. It sold for as low as $99 at Best Buy (based on my googling), and has very good audio qualities for the price. The problem is they seem to die pretty quickly – usually in a matter of several months. So how did I happen across one of these receivers? Well, one day I was hauling off the trash (around here we have refuse centers where we take our trash and recyclables) and happened to notice a pristine-looking tuner / receiver in one of the trash bins. The power cord had been cut off, but besides that, it looked brand new. I snagged it up and took it home, where it sat for a good month before I finally decided to check the thing out.

Once I finally got around to trying out the new receiver, I headed on over to the local Goodwill, where I purchased a cute little ceramic Potpourri warmer for $1.95. Although it had a nice country look to it – blue enamel glazed in pretty patterns, what really caught my eye was the heavy-gauge power cord with polarized plug. So after returning home with my prize I removed the metal plate from the bottom of the pot, and found that I had done someone a big favor. The leads going to the heating coil were corroded and burnt through, and were completely shorted. At best this thing would have blown someone’s breaker, and at worst burnt down their house.

So, new power cord in hand, I opened up the receiver, grafted it on in a quite professional way, fired it up, and… it worked! All the inputs, all the outputs, the thing worked perfectly. Yes, I still had this nagging feeling in the back of my mind, “exactly why was this thing laying in a garbage bin with the power cord cut off?” I inspected the inside thoroughly, checking the top of the mainboard for anything that looked burnt or browned from overheating, and everything looked new. After sorting out the rats nest at the back of my entertainment center, I had all my speakers hooked up, all my audio and video from my DSS receiver, video game console, DVD, etc routed in and back out of the receiver, and I was ready to go. I fired it up, and couldn’t help but grin at how well it worked.

My next concern was the remote. Unfortunately the remote was not to be found in the trash bin on that fateful day. I consulted the on-screen manual for my DirecTV DVR, and tried both the KLH codes it listed. Neither would operate the receiver. Now I was really concerned. If I couldn’t control the volume from my DirecTV remote, then the thing was almost worthless. I thought maybe I would have to invest a good universal remote that would control the KLH. But before I had to do anything that dramatic, I first consulted Google. Lo and behold, I came across this page, and if you’ll scroll down to the KLH brand, you will see three codes. Yes, it contained the Lost KLH Code of the Ancients, hitherto thought lost to posterity: 31428. And, you guessed it, that third code operates the KHL R7000 receiver. So now I’m really on a roll. I mean, this must be meant to be, right? Not so fast…

After a solid week of use disaster struck. With a loud “pop” out the speakers, the R7000 became deathly quiet. Regardless of the input source, or the volume setting, or anything else I would try, there was silence. The LED display was as lively as ever, but no sound emanated forth from the speakers. More googling, and I found others that had the same problem, but no solution. So I decided to try and fix this thing, once and for all.

The first step any good repairman will use is to bang on the item that is not working properly. This

simple technique illuminated the problem immediately – after a few good whacks with my fist, the tell-tale “pop” came out of the speakers. I knew right then I had a “cold” or open solder joint. I removed the cover, and using an insulated probe continued my “banging” in a more refined manner, by tapping on individual components. I started with the relays, because they sometimes stick. Next I moved onto the power transistors, because I knew they were the stars in this show – they switch a lot of power, get really hot, and determine what wattage the amplifier can handle. The stress these components endure is why they are one of the main things to go out in any power amplifier. All the actual audio transistors are mounted on a large heatsink on this receiver, which runs the entire width of the case. They all looked good, and had plenty of thermal paste binding them to the heatsink. So I moved on to three other power transistors located at the center of the mainboard that were mounted to their own little heatsink – there I struck gold. After tapping on one of the transistors the speakers “popped” and I saw a spark at the base where the leads go through the mainboard. This thing was as good as fixed already. The next problem was how to get at the bottom of the mainboard, where all the solder joints are at. I nearly goofed at this point, and was about to start removing over a dozen screws and connectors and various other hard-to-remove-things to try and get the mainboard out of the chassis. Fortunately I took a look at the bottom of the receiver, where I found a convenient access door held on by seven screws. After removing the door my hunch was proven correct – there in the center of the mainboard, at the base of the three power transistors, was obvious thermal damage. The mainboard had been so hot that it blackened, and some of the circuit board coating had blistered. A quick inspection revealed that all three legs of the middle transistor had open solder joints. The components had gotten so hot that the solder had been softened enough to fall away from the legs (see 3rd picture). So now the task was simple – I fired up my soldering station, cranked it up to 850F, and re-soldered all the solder joints in that area of the circuit board. I tried to simply reflow the existing solder but there wasn’t enough, so I just added some new to the existing.

I put the thing back together, fired it up, and had an even bigger grin on my face the second time around, because that nagging question “exactly why was this thing laying in a garbage bin with the power cord cut off?” was answered – because of a little solder joint that needed to be reheated.

When I get around to it I will blog about the various free items I have repaired over the years that we use daily. The total cost of the items would have been several thousand dollars if they were purchased.

Until then, maybe some R7000 owner will stumble across this page, and be able to breath new life into their little receiver.

Update: It’s been 8 months since the repair, and the receiver has worked flawlessly, day in and day out.  It’s been operated somewhere in the neighborhood of 1000 hours since the repair.

Update: Now it’s been 16 months, and the problem reoccurred.  This is no surprise, as the R7000 is improperly designed, and cannot dissipate enough heat from these transistors (they need heat sinks!).  A couple minutes worth of soldering and everything is back to normal.