A lot of what I write here is going to be old hat to most readers, I believe. In fact, most readers will know far more on this subject than I do. At the same time I hope to spark an interest in others to tackle a similar project. In part, by showing that even someone with my limited electronics knowledge can do this (with the advice of others and the internet). So let's get started.
Tearing out the old parts should be an easy part of this project. As I stated at the beginning I am going to be replacing almost everything so I can be a little more carefree in my steps during this "destruction" phase. Those who may only be doing a line or phono section update will need to take far more care in how you take out the old parts. Nevertheless, it's still a good idea for me to have a loose plan of attack. I suspect these steps will change a bit as I really get into the project, but here is what I'm thinking now.
Overall plan
- Completely disassemble the Citation I into its parts. Just like when the kit box was opened.
- Order all the replacement parts. This can happen in parallel with the first step.
- Clean all of the hardware as close to an "as new" state as possible.
- Assemble the Citation I according to the Harman Kardon assembly manual.
For anyone else who decides to tackle a similar project I have one bit of caution - Be VERY careful with the tube sockets. According to Jim McShane there are no identical replacement parts for the original sockets. The originals seem to measure out at 3/4" openings with 1 1/8" centers for the mounting screws. You may be able to find this size, but they probably won't accept the original tube shields. The only way to get identical replacement sockets is to cannibalize another unit.
Step 1 - Completely disassemble the pre-amp
We need to have a plan here as well. Here's the order I think I will be following.
- Tear down Terminal Board B (the topside board) - removing all parts and wire connections.
- Remove all connecting wires and components from the top row of tube sockets.
- Turn the pre-amp over and first remove the wire bundles that connect to the RCA jacks.
- Remove all Terminal Board A parts and wire connections.
- Remove all connecting wires and components from the bottom row of tube sockets.
- Deal with the power supply section. I'm not sure how I will handle this. This is the one part of the rebuild that will deviate from the stock assemply instructions. We'll come back to this later.
- Take apart the rest of the pre-amp, down to the individual hardware components.
Heat up the soldering iron, get out my solder sucker pump and braid, some fresh solder and off I go. As I attacked Terminal Board B it didn't really seem to matter where I started. So I picked a random capacitor and started in.
The component parts were originally attached to the terminal boards by wrapping the wire at each end of the component 180 degrees around a terminal lug, clipping off the remaining wire, and soldering. With most units I have worked on the builder used a pliers to crimp the end of the wire tightly around the solder lug before soldering. Also, many units you will find out there have too much solder applied, especially if they have been repaired. So the trick in removing the parts is to first get all that excess solder off so you can find the end of the wire and then to pry the end of the wire away from the solder lug so that you can more easily use a needle nose pliers to finish the removal.
I use a cheap spring loaded solder sucker pump (under $10). Place the hot iron in contact with some old solder on the terminal lug and hold it there until it melts. If the old solder won't melt (sometimes it seems like it just won't) apply some fresh solder to the lug. This is guaranteed to work. Have the solder sucker pump ready to go when the solder melts, get it as close as you can to the iron and trigger the pump. I keep the lug hot and immediately pick up a small chisel-like solder tool (sold as part of a solder kit for under $10) and start prying the end of the wire away from the lug. At some point I switch to a needle nose pliers to complete the job of pulling the component away from the solder lug.
From that description you knowledgeable readers know why it is much easier to work on a unit if you plan on throwing away all the parts. You don't have to protect the rest of the components on the board that won't be discarded. If I was planning on keeping some of the caps and resistors I would have to minimize the time the lug was kept at solder melting temperature. The old PVC insulated wire is especially susceptible to melting in this old equipment. I would have used small heat sink clips on the components that would be kept.
I would also have to be careful where I was sticking the soldering iron. The soldering iron will slip from time to time. When it does it usually makes contact with a wire or some other part. Result - damaged insulation.
Proceed piece by piece, removing all the components and wires from the board. I discovered from the work I did restoring my Citation II amplifiers that it is FAR easier to remove parts from the terminal board while it remains installed in the chassis. This is not supposed to be a brute force activity. Nevertheless, I found that removing the board from the chassis first makes it hard to remove parts as the board is hard to keep stationary.
When I had removed everything from the board I turned my attention to the tube sockets. Remove the wires carefully here as well. CRAP!!! I just broke a pin lug off of socket V3 trying to pry off the attached wire. I can't believe I just did that! An e-mail the next day to a reliable source turned up a spare used original socket for sale... along with a reminder to "be careful, those sockets are scarce." I completed the other sockets V1 through V5 without incident.
Once everything was removed I went back to the terminal board. Using the desoldering braid and a hot iron I went to each terminal lug and removed any remaining excess solder. Again, if the old solder didn't melt the application of some fresh solder did the trick. Here's a photo of the end result. Note the solder pick tools (red and yellow handles) off to the right of the chassis.
Time Spent for the above work: 3-4 hours.
On to the bottom side of the unit. Flipping it over reveals Terminal Board A. Look at the picture below and note how the two bundles of wires leading to the RCA sockets make it difficult to work on the terminal board. Especially if you need to be careful because you are not replacing everything like I am.
I'd like to point out a few curiosities that are visible in this photo. First, look towards the top center portion of the photo, at the bright blue wires. See anything odd? The two lengths of wire are attached to one of the convenience outlets. Each wire loops back to itself. Someone apparently wanted to disable the outlet. I can understand that. What I don't get is why they used such long lengths of wire.
The other oddity is the loose ends of wire that were formerly attached to the RCA jacks. Specifically, you can see the red and white/red wires in the middle of the photo hanging in mid-air. These wires were attached to one of the A and B output channels. They have been replaced by the black Mogami wire. Similarly, there is an orange and white/orange pair of wires on the left side of the photo that also were clipped off (from the phono input jacks) and left hanging.
We'll uncover a couple more oddities in my next posting, where I remove the components from the Channel A board.
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