Good Afternoon all,
The first step after I got prepped and organized was to install the spacers. Super simple. There are six of them...stick in screw and twist on spacer.
I forgot to mention it, but I cleaned the PCB with a little contact cleaner before I started. I don't have any alcohol for some reason, so I sprayed the Deoxit onto a shop towel and wiped it down real good.
My next step was a little vexing right off. Installing resister R1 stumped me. I searched for it on the board and the pictures but couldn't find it anyhwhere. After closer scrutiny, I saw that there was a (B) on the parts list after the R1 designation. It turns out that R1 is actually resistor "B" in the loading section. It is the resistor that gives you the standard 47K load for the MM cartridge. It lines up with dip switch number 2, which is the only switch that is in the on position to get that load. So don't get confused, just know that R1 = B.
You can see in the above pic that I installed R2 and R4 and was planning to come back to R1 later, but the answer occurred to me.
In the PH16X, any components that would end up being taller than the spacers need to be installed on the bottom side of the PCB so the next step in my process was to stuff everything on the top side of the board. This includes all of the resistors, the tube sockets, and two transistors (J1).
To any of us regular builders the next descriptions are pretty common, but I want to show anyone that thinks that this stuff is too hard for them that it is a possibility and you have to start somewhere.
Sizing and bending component leads; resistors in this case.
I've got an LED magnifying lamp clamped onto my bench and readily available. It seems that as my age advances, my vision up close contracts. Time waits for no man, I suppose.
Bending resistor leads to the correct size and orientation takes a little bit of practice. I first make sure that the resistor size number is showing on the top to help with troubleshooting later. My second goal is to try to bend the leads so that the resistor is centered over the screened picture. I also work so that it fits into the holes snug enough that the piece doesn't move when I flip the board over. I generally accomplish this second goal about 50% of the time...sometimes when I flip the board to solder the piece in, i have to bend the leads outward to hold them in place. Winsome...losesome.
Here are some pics of bending resistor leads with duck-bill pliers:
Before I slide it in to the correct place on the board, I double check the part number from the BOM. Then I slide it in snug against the board. 1/4 and 1/2 W resistors can lay against the board, but the bigger ones need some room to breathe. (More on that later.)
If I bent it perfectly, it is just a tiny bit snug and centered over the printed location. If not, I bend the leads out on the bottom of the board to hold it in place. Because of the symmetry of this particular board, I generally install and solder two resistors at a time. Here's two ready for soldering:
I then solder. I put the tip on the board so that it touches the lip of the hole and the component lead. After a few seconds it heats up sufficiently so that when you touch the solder to the lead it flows nicely. It takes some practice but the learning curve is not too steep. If you touch the solder to the iron, the solder melts but doesn't flow into the hole and bond to the lead properly because they are not hot enough and you may end up with a cold joint. Joints should be shiny and not grey and dull. (Cold solder joint.) If you do get a cold one, just re-heat it and flow a little fresh solder into the joint and it should fix the problem.
After that I snip off the lead, hoping it doesn't shoot my eye out, and make sure that it is a good joint and isn't bridging over to any other spots on the board:
From there I just continue to populate the board. I always double check the part number on the actual component with the BOM, and I check each part off the list as I install it. I just go straight down the list sequentially until I'm finished.
Here's some incremental progress:
As I mentioned earlier, the higher wattage resistors will produce more heat. These guys need to breathe so they are spaced above the board a bit:
Auto focus is tough, but you can see the space under the largers.
Eventually, all the resistors are in. Great success!
I'm that guy that tries to align everything perfectly with everything pointing the same way. Even the slots in my screws tend to be in sync. (Skizo might be able to relate.)
****Helpful Note**** When I got to R26 and R27, I lost my groove because the lead holes on the PCB are a little bit further apart than EVERY OTHER resistor on the board. My muscle memory was established and those guys wouldn't fit. I had to resize my process when I got to that point!
Next came the tube sockets. I was able to stick all four of them on the board and then flip it over. They were about one mm taller than the spacers so I could lay them flat on the bench. From there I soldered two pins on opposite sides of each socket and then flipped it back over to double check that my sockets were level. I've had some instances in the past where one of them wasn't quite level after soldering all nine pins and that is no fun to fix later. For the OCD alter ego that lives within me, a tube that sticks up slightly crooked would deny me the ability to sleep nights. Verifying that they were level, I flipped it back over and then soldered two more opposite pins on each socket and then checked for level AGAIN. After I felt my inner peace exhale, I soldered all the rest of them into place and all was good with the universe.
Next went in the transistors J1. Transistors can get junked if they are cooked too hot for too long, so try to keep them away from the board a bit and don't fall asleep while applying heat to the leads.
Slid in.
I then clipped the leads and very gently bent them over to fit into the proper clearance, Clarence.
And KABOOM!
The top side of the board is stuffed!
I then got started on the bottom side of the board installing the capacitors. I used the same process of checking against the BOM for each part number and each value, checking off each one as I installed it.
C1 went in first and I used the heatsink from the PS board to prop up one side as I soldered:
From there, everything is smooth like buttah. The rest of the caps go in. (Perfectly aligned with all print facing the same direction, of course.
)
No magic here, everything is easy because there's not too much bending and fitting to be done.
A quick side note:
I had to decide if I was going to install the load section resistors on the top or bottom of the board. I debated that maybe I'd want to see the values of the resistors later if I ever needed to change cartridge load. Although i definitely want the DIP switches to be on the bottom, I decided to just leave the resistors on top. It makes no difference functionally, but may make things easier in troubleshooting later if there is a problem. I decided that I'd strive to just put everything in the right place the first time around.
That is where I am right now. I have to install the DIP switches and the load capacitors and then I'm ready to move on to the power supply board.
.....what remains.
More to come as I get to it. Today I will receive the shielded cable that I ordered. It should be in the mailbox right now.
Thanks for reading again!
-efg