Heres the update for reference and others whom may trouble shoot this on their own in the future.
I found a burn mark on the SF-CA card (spindle drive top card) on the pin connection for 5v dc from power supply. Then I found on the back of the SF-CA opposite side of two white tall blocks (resistors??) located lower left side of card was melted and bubbled. I always noticed that where the white blocks connect to the board they were brown. I just found out that this was actually burnt. Needless to say the SF-CA card is "Fryed". When connected the 5v test point shows 5v and then intermitantly drops to 3.5v. The digital led goes crazy. Thats the only way to explain it. The numbers jump around and change constantly with no method to its madness.
When I unsnap the SF-CA from the power supply SF-PW and power up the power supply seems to perform correctly but it might be producing noise based on this event.
I decided to purchase the exchanges for both SF-PW and SF-CA. My customer is ready to kill me again and so I have to bit the bullet and get running again. I expect that Ill be up and running today.
Heres the fun part: I removed the entire spindle drive unit and base unit from the panel. It weighs about 80 lbs? A fork tuck is needed for this, I found that the drive can sit on itself standing up in the same fashion as it is mounted. That helped with installation once I figured it out I was able to stand it up and drive it up into position, bolt it up, done.
I removed the drive so that I could check the resistors and inspect the connectors for shorts. I found none, but I did find one out of about 65 toung and groove connectors was completely loose and just fell off as I was removing it. I fixed that, realizing that it could have caused the problem. I also replaced the diodes because they were slightly out of tolerance according to the test proceedure in the maintenance manual.
Im happy that the resistors are all good because they cost $488 each from mitsubishi or you can try an after mkt replacement for $150+-. Quite a risk to take I thought due to the cost of frying a SF-CA board ($1850).
Finally as I went over the machine again I found the main power connections on top inside spindle motor seemed fine at first glance, the rubber covers were all intact protecting them from shorting. But, when played with them I felt looseness in the connection. It turn out that two out of the three phases were not tight. There is a nut and bolt that connects the two wire terminals together. I tighted them proplerly and thought, hmmmmmm. Of course this may have caused the burn up. If not then in the future it surely would have.
In essence, I found the base unit has no shorts (although I havent checked the capacitors yet, which I should do before putting on the new SF-CA) , the SF-CA is fried which is being replaced, the SF-PW is being replaced as a percausion, and at least two power connections were loose and are corrected now.
I hope that does it. Will advise and thank you for your input. BTW the exchange cost of the FR-SF AC Spindle Drive Unit is $8500 (none avail) and new its $14,000 (one avail). A repair program is availible but the cost to ship it alone for me was $500 round trip and I confirmed with Mitz that any new parts it needs are added to the cost, in otherwords there are no breaks for you if you send it in to them for repair. Transistors are still $488 each and boards are the same cost. Ouch!!.  |