Today was the standard
day with a trip to the hospital after breakfast. After that I arrived at the
clinic at 8:30 and started immediately working on that centrifuge (the one with
the lid latch that hasn’t been working). Anyways I couldn’t get it working
anymore so I just left it for a bit and decided to open up the larger
centrifuge that was working and try to check the diodes and brushes. The larger
one was a bit of an annoyance to open as the base had 5/16ths hex bolts on it
(think they were that size) and had to torque some of them using this large
wrench on the screwdriver. Anyways, after getting that open I was able to look
inside the clean area after I unscrewed the motor mount plate from the base (I
thought this would turn into another one of the small centrifuges, but luckily
it did not). Anyways I got that off and eventually removed the base cover and
look at the motor. The motor looked fine and I couldn’t get to the brushes and
they were sealed behind this mechanism I’ve never seen and didn’t want to mess
with (so I left them alone and sealed the case back up after looking a bit at
the board). I then got everything back together (including the annoying limit
switch that sits against the motor mounting plate to check for vibrations I
think) and the centrifuge still worked and the door still sealed as before (so
that was a win). The centrifuge also is just as quiet, so I’m counting that one
as good. Around 10 I opened up the one autoclave that had been having an error
and everything looked fine, so I filled it up with water. At this time one of
the nurses brought me a printer that was not printing so I opened up the back
and pulled out two pieces of paper which seemed to be jammed in there. After
that I tried powering on the printer and it would not turn on. I also let the
autoclave run a cycle and it heated up to the temperature, but it alarmed after
9 minutes of the cycle; throwing up a “error 08” message and stopping the cycle
(and just alarming). So I left the unit to cool down all day (which literally
took until like 4:30). At this point I was in the middle of taking apart this
printer (or at least trying to, but the design did not seem to have any way of
accomplishing this, so I would take out a couple of screws, look at the housing
and then take a break. I eventually got open the printer to the power supply
and measured across this one diode and found it measure 0.198 and 1.3 (the
first number being low). I then decided to swap the diode form the centrifuge
board to this place and then check if the printer worked. So I had to find a
way to expose the power supply which seemed to be a task in and of itself
(which involved removing the undercarriage and disconnecting 6 or so cables
running to the USB board). Before doing that I measured some voltages on the board
and got that these 4 diodes were each dropping 75V across them (probably the
rectifier diodes) and the “bad” diode I had found was only dropping a volt or
so. I had to take a break from the printer and work back on the centrifuge as I
decided it was time to just stick the front on and hope for the best. So I
attached the front and put the screws in to find the door actually sealed like
it used to! I was so excited that I hit the door release button and it went bad
to being easy to open -.- // false hopes. Anyways it still seals pretty well and
has the ability to run and the door to stay closed, so I explained this to Guillermo
and he said it’s fine. The centrifuge also works really well as I ran it
through its hour cycle at the high RPMs and it worked and was quiet. I also
tried the autoclave and found that it has two leaks (one by a large pipe end
and one below the tank in the corner (so those have to be addressed as well)).
During this time I also was waiting on lunch and tinkering with the printer and
asked Guillermo for his contact info (so I can pass it along to EWH). After
that I had lunch in the AC board room (it’s so cold in there) and waited for
the autoclave to cool in addition to tinkering more on the printer and getting
the power supply out of the bottom (after more work). I then desoldered the
diodes from the different boards and got the diodes switched on the boards. I
then plugged everything back in and tested the power supply and it still did
not work correctly -.- . I was measuring voltages on the ribbon cable connector
where it should be 5V and 24V, but the voltages were not there; indicating
somewhere the power supply is broken. I then thought I might be working on a
fridge at some woman’s house (but I found out later that Monday would be
better). Before I was fully able to put everything back on the power boards I
had to head to the hostel to meet Kevin at 3 to go test O2
concentrators with the Tulane research group’s prototype. We arrived at the
hospital and Popo said there was a lab oven that wasn’t working and needed to
be addressed now, so we went and looked at it and what had happened was that one
of the DPST rocker switch’s terminals on the back had broken off. This meant one
of the power cords was just hanging wildly in the air. We looked around for a
switch in the shop and dump, but couldn’t find anything. So then Kevin and I
went to several hardware shops that didn’t have anything like it (but the
Constrúmas place mentioned this autoparts store outside of town). I then
decided to try there and made my way back to the hospital to grab a taxi there
and Kevin went back to check on Dan (who had been released and was at home now
and it getting better slowly). I talked to Marlon who gave me a ride all the
way out there in his pickup truck thing, but both places didn’t have the type
of switch (just a normal DPST rocker that could go in a car or something
similar) (they had this weird headlight switch, but nothing else). On the way
back I decided that I could still use two of the 4 connections and then just
splice the other two wires together (as Kevin had mentioned something similar).
So I got back and Popo wanted me to splice in this switch from a compressor
which would require cutting the 4 crimp and slide terminals off, so I took that
one some diagonal cutters and tape and a screwdriver and the switch and went to
work on the machine in the lab. I decided that I could use the broken off
terminal and cut it down to slide the other two crimp slide terminals onto it
and make the connection. This actually worked and the unit powered on!
Unfortunately the first time I had the switch in backwards and had to swap
connections around a bit, but it eventually worked again! BAM! Fix! (it was
good too because they needed this for the next morning too.) After that I
headed back to the hostel and then to the clinic to finish up there and get an
autoclave. I soldered the diode back into the board and then packed up tools
and grabbed the autoclave with Kevin (another that won’t power on) and brought
it downstairs where we loaded it onto the bed of a pickup truck and one of the
guys backed the truck up the street to the hostel. After that we brought the ’clave
in and chilled the rest of the night. Got a ton of rest. So nice. Peace! No
work tomorrow!
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