Need Wiring/ Service Schemtaics

Not a bad day except for you in that the CSR told you the truth. Seriously, the TJ6 series centrifuges came out in the late 70's and have not been sold for about 20 years and service was discontinued about 15 years ago. The only way that you will probably get any documentation at all would be if you get to know a Beckman service engineer that still has access to the online documentation. Beckman went all electronic with service manuals over 10 years ago so any paper copies, if available, would be outdated at the very least. There's really not a lot to the centrifuge. Speed control was through a variable light dimmer that controlled the voltage to the drive. Not very high tech and most of the problems were more mechanical in nature than electronic usually associated with the door latch assembly. If you have a specific question then please ask it on this forum and I'll try to help.

Don

Don,

I can get the unit to power on but the motor will not turn on. Here is what I have done/ checked thus far. 

Motor bushings/ run test good.

Belt, good condition. Break resistor tested works.

Timer, start switch, brake switch and rpm all seem to be in working order.

Lock cable underneath adjusted to 1mm from rotor base.

There is another switch underneath the unit connected to the PCB board. I tested that too and may need to also be replaced. 

Imabalance switch volt tested and seems to work.

I am in agreeance with the possibilities of medchanical issues with the dor lock itself. I did have to overide the lock once. When I looked to check the imabalance switch I tried to understand the mechanics and it did not make a lot of sense to me.

I have seen the link to Ozark's part list, I am drawing conclusions towards a new imablance switch (or 2) or New speed switch or new relay or even a new PCB board, those capacitors are not built for forver right?

What specific mechanical issues would would I be looking for with the door latch? 

The biggest issue with the door latch was with the adjustment with where the end of the door cable hits the bottom of the spindle assembly. When it's not adjusted correctly, the end of the door latch cable actually bends off to the side of the pulley when the door latch is closed. Obviously not something you can see when the centrifuge is in normal use but usually, when you remove the rotor, flip the centrifuge on its back, remove the bottom cover, and open and close the door latch assembly and see if the cable hits the pulley straight on. If it bends off to the side at all the centrifuge will not run.As I said previously, this centrifuge model is very old and extremely simplistic in its design. One other simple issue that gave the impression that the centrifuge is not working properly is failing to turn the speed control know up to maximum in order to get it started. I know that it doesn't seem like this should be the case but by turning the speed control to maximum, you will give the drive motor full voltage which may get the rotor spinning and after it does you can then turn the speed control back to the speed that you actually want to spin at. In the past, I did have to replace the speed control pot from time to time because they do fail. It is a very old style lamp dimmer and if its an original part it could be suspect.Don

Don,

It took me a while to get back on this project but I believe I found the culprit. WHen taking apart the latch assembly it is clear that the cable bends and does not make any contact. The cable apears to be in the proper orginal state that is was fashioned to, just bending wonky. The is a spring and washer cap on the cable as well. 

Any recommendations to remedy this?

Thanks

I was wondering what happened to you and your TJ6.  Here's what you need to do to get it fixed up.  Flip the TJ6 onto it's back and remove the base cover and I believe that you have already done this.  There is a clamp that holds the door latch cable in place.  With the door latch in the open position, but first tape or oterwise secure the door closed, align the door latch cable so that it is as close to perpendicular to the bottom of the spindle hub.  After adjusting its position, try to close the door latch.  The wire inside of the cable should engage the bottom of the spindle but should not bend.  IF it bends, pull back slightly on the cable while maintaining the perpendicular position until you can open and close the latch without the end of the cable bending but with the cable still in contact with the bottom of the spindle.  It may take a little bit of time and the sheathing around the cable may have the imprint of the clamp upon it so you may actually have to break the clamp free from the cable in order to make your adjustments.  Give it a try and let me know how it goes.

Don

I have adjusted the cable on the bottom of the spindle and that part seems to be in order. However, still not firing up. I am curious about the other of that cable? Does that need adjusting too? How is that supposed to look?

Once I go through the start up phase everything seems to be working up to the point I press the start switch, I clear a click and nothing fire up. I will only hear that click again if I power down and start all over again as oppsed to continuing to push that start or readjust settings without powering down. Im beginning to feel there may be a lost connection somehwere in the start switch??

One thing most people aren't aware of with the TJ6 is that to getting spinning to begin with, it is best to crank the speed knob up to maximum and then adjust your speed accordingly.  Also, the same speed controlsetting will result in different actual speeds because of the lack of more sophisticated speed control.  Afterall, the speed control is nothing more than a light dimmer.

Having said all of this, does the red LED go out when you hit the start button?  Also, make sure that the imbalance switch is wired correctly.  You can just try moving the connections around to check to see if that is the problem.

There's not much else to check but try the stuff that I suggested first and get back to me.Don