[lrhorer]

Well, after several years of having problems with my S3 it has finally died. Just this morning actually.

I opened up the case again and noticed that the large capacitor on the power board is rusting. Something is leaking out of that thing.

Unfortunately I do not have the skills or tools to replace just the capacitor so it looks like I'm stuck replacing the entire power board.

An $8 soldering iron and a $5 roll of solder from Radio Shack are all the tools required. While the Tivo motherboard is a multilayer board using surface mount components, the power supply is just a single layer board with axial lead components. Re-working an SMD multilayer board requires some skill and a steady hand. I don't recommend it for someone who is not already handy with a soldering iron. A low-frequency single layer board however, is much easier to wrangle. Just be sure to keep the tip of the iron clean, heat the joint, and add the solder to the joint, not the iron, and you should be fine. A bit of solderwick or a solder sucker can help with de-soldering, but honestly with large capacitors it's really not necessary.

Of course, it's up to you, but frankly, I can't imagine shying away from a soldering job this simple. Honestly, this is nothing I would have hestitated to tackle when I was 12 years old.

 

[lrhorer]

I wonder how many other Series 3 units are experiencing this problem.

A lot. It's a well known problem. I have several bulging caps on one of my S3s. (I haven't opened the other recently.) If they go plotz, I'll drag out the old soldering iron.

It looks like they used quality capacitors on the motherboard, but went cheap on the power supply components.

Yep. I suspect they may have purchsed the power supplies as assembled units from some OEM manufacturer. It's what I would do.

 

[lrhorer]

You left out the part about these particular electrolytics being polarity sensitive (as are probably 99.99% of electrolytics), and to take careful note of how the old ones are hooked up so as to not put the new ones in "backwards".

True. A polarized electrolytic capacitor can explode if installed backwards. I wouldn't say 99.99% of electrolytic caps are polarized, but certainly more than 99% are. Non-polarized electrolytic capacitors certainly exist, but they tend to be rather small as filter capacitors go, and they are considerably more expensive than polarized electrolytic caps.

 

[lrhorer]

if you are into electronics, geeky in nature or just enjoy a good mystery. Dell got hit particularly bad with their Optiplex GX270's - we had to eventually replace thousands of them

<Light bulb goes on> Ah! My company supplied me with a GX270 whose power supply failed. I always thought it funny, because modern power supplies are so reliable. I'll bet that's what it was.

 

[lrhorer]

When did you purchase your S3s? Reason I ask, I'm looking to buy a used S3 and was hoping to avoid any bad caps if possible. But of course I'm not sure if Tivo switched cap suppliers upon learning of them being defective.

2006 and 2007. If it's an oriiginal S3, then it almost surely has caps that may suffer from capacitor disease. That doesn't mean they absolutely will fail, but it's reasonably likely. Replacing a handful of electrolytic caps is just no big deal, though.

 

[lrhorer]

Assuming that current flows from positive to negative is known as conventional current theory, and still gets used a lot, especially in analyzing negative ground systems.

It is not a matter of theory, it is just a convention, and there is nothing wrong with flipping the conventon, as long as one does it throughout one's analysis.

Electron current theory says that the flow of current is actually the flow of electrons, and it goes from negative to positive.

I'm afraid that is not entirely correct. Electrical current is actually a disturbance, not the flow of charges itself. The flow of charges is usually quite slow, perhaps less than 1 meter per second, and highly variable, but the electrical disturbance travels at the speed of light, only slightly slower than that in a solid medium. In a given medium, it is not variable at all. The charge velocity is dependent upon the potential difference (voltage) and the mass of the charge carriers. Finally, it does not only arise as a result of electron flux. It can also be created as a result of a flow of positive charges, such as may be the case in an electrolytic solution, for example. In semiconductors, it is the result of a flow of neither positive nor negative charges, exactly, but rather as the result of the propagation of "holes" in the semiconductor material. If you have a battery powered device at hand, the flow of electrical current may be the result of all three types of charge carrier flux. (Note, too that in an electrolytic solution, negative charges may be transported, but the carrier may not be a simple electron. It may be a negatively charged ion.)