Ever wonder what's inside a switching converter?
Well stick around because you'll find out here, right now!

Here it is, the famous PD9160 about to enter the emergency room for inspection and minor surgery.

This particular unit was given to me from a friend with the complaint that the output was intermittent. No other details were given.

Upon initial inspection, no physical damage was noted however the unit did show signs of being used for at least a short time.

On power up when the unit first arrived, it was quickly pronounced DOA! 00.00 volts output, is as dead as it gets. The user replaceable 25 amps fuses (all three of them) were good and intact, so no problem there at least.

In the instance of intermittent problems, shock testing can sometimes show them up. A few slams on a hard surface like a workbench will do, in this instance however, no change in the converter's performance was noted, still DOA.
Opening the PD is a simple task. Armed with a hand drill and a 5/16" bit, the four "Pop-Rivets" on the side panel are drilled to remove the heads.

Shown here are the four rivets already drilled. Once completed, the two screws on the top of the PD are removed and then the lid comes off exposing my favorite parts, the "guts".

Because I have an extensive electronics background, I always get a chuckle whenever I see one of those labels stating, "No user serviceable parts inside." Yeah, right! Let me at it!
No need to drill the heads off these rivets, simply remove the one machine screw shown here to loosen the output side assembly.

Also shown here are the 3, 25 amp user replaceable fuses. These fuses are used for reverse polarity protection in case of connecting to the battery backwards.
Two more machine screws at the other end of the PD and the power input end panel comes loose and can be removed as much as the internal wiring will permit, which isn't much.

Nice big heatsink, yea gotta like that!
Unplug two small connectors and Wal-la, the output panel complete with fan and TCMS connector can be removed in one chunk as shown.

This is as much disassembly as can be performed without actually unsoldering or cutting wires or removing the heatsink.

Though this pic makes the PD look pretty crowded inside, surprisingly, it's really not got all that much stuff in there. A lot of the real estate is taken up by a transformer, a couple medium sized capacitors and a few chokes. There's only three integrated circuits, a bridge rectifier a medium signal transistor and a couple high power transistors, probably MOSFETs. The rest is just a handful of resistors and small capacitors and a couple diodes here and there.

So far, one of the identified IC's is a TL3845P current mode PWM controller. Another is a common quad OpAmp made by ST, an LM2902N. Another identified semiconductor is a 60 amp dual diode made by IR (International Rectifier) 63CPQ100.

Clearly the most difficult part to replace would be the transformer (vertical silver part in the middle of the board) as there are only a few numbers stamped on it and no manufacturer so if that ever died, it'd be junk for sure, but everything else is replaceable and transformers rarely die. If one was courageous enough, it could be rewound by hand, but it would be a job. To make things harder, the PD people have chosen to remove the part numbers from two components. One is an 8 pin dip IC and the other is a high power FET. I'll see if I can figure out what those might be.

Of the two little white connectors show here, only the 4 pin one is used in this model. It connects to the TCMS connector located on the output panel. The bottom two pin connector, as you can see, is labeled for use with lead acid/gel-cell battery technology. Looks like it's a simple matter of installing a jumper on this connector to enable the gel-cell charging characteristics of the PD. It's interesting as this is something that would be installed only at the factory and not by an end user.

Also note the fuse above the two connectors. This is a slow-blow type fuse with solder pigtails. If it blows for some reason, only the factory or qualified repair person would normally replace it. This one checked out good, so that's not a problem. I believe this fuse is to protect the wiring going to the Charge Wizard which requires power from the converter to operate.
Here's the solder side of the circuit board. As can plainly be seen, some areas of the board are much cleaner than other areas. These are the dark brownish areas on the board. The residue is left over rosin flux from a portion of the soldering process. The reason for this is that the smaller components like resistors, integrated circuits, capacitors and such are installed first, then wave soldered. The board was probably cleaned after that step of the manufacturing process, then, other items are installed and soldered by hand. The hand soldered items, usually wiring, comes as the last step of manufacturing, just before the final assembly and closing up of the case.
Shown here is another internal fuse. This is a low current fuse and the fuse link itself is very small and can barely be seen. I can't get it's rating without removing it and since it's still good, there's no need to remove it unless I decide to do some serious digging into the wiring and take the time to create a schematic of the unit. With the one integrated circuit with it's part number removed, it would be a good challenge to try to figure out the diagram, but likely not completely impossible. Because the part numbers were removed from the two semiconductors, this suggests the parts are available off the shelf, but by removing the identifying numbers, the PD people have made it very difficult to figure out what they are. Obviously, they don't want people making clones of their product and have increased the level of difficulty to repair them by quite a factor. We'll see what happens in the future with this. I like a good challenge!
Here we see the culprit. He's trying to hide in the shadows just above the torid choke. This fuse was blown, but you couldn't tell by just looking at it. This is a 15 amp 3AG ceramic fuse with axil leads. Again another servacable part, but not by the adverage Joe. Replacing this fuse brought the unit back to life, but I haven't done any testing with it at all, other than just checking it's voltage output.

I'll post more information here about this project as it progresses along with more pics. Yo-