>>> 'nrc' problem from gtdu -- Wed Feb 21 22:42:15 1990 <<<

the vaccum is too low. the cryo pump need to be regenerated.

>>> 'nrc' problem from parrish -- Thu Feb 22 06:44:12 1990 <<<

system is being regenerated.

>>> 'nrc' problem from parrish -- Thu Feb 22 12:34:44 1990 <<<

problem:    base pressure high

cause:      accumulated evaporating time

solution:   regenerated cryo-pump. system base pressure is 3x10-7 

>>> 'nrc' problem from jgtsay -- Fri Feb 23 00:23:25 1990 <<<

esNi boat is broken. I can't find a replacement.

>>> 'nrc' problem from jgtsay -- Wed Feb 28 15:59:02 1990 <<<

It seems to me that some one forgot to close the mech pump. Now the ion pump cannot function .

>>> 'nrc' problem from parrish -- Thu Mar  1 09:35:34 1990 <<<

problem:    ion-pump not function( should read cryo-pump, there is no ion-pump
            on the nrc).
cause:      undetermined 

solution:   system gate valve was open and chamber pressure was 3x10-7, I
            vented the system and pumped it back down, pressure was the same
            I found no problem. system is up.

>>> 'nrc' problem from jgtsay -- Sun Mar 11 17:15:59 1990 <<<


The venting process took too much time ( about 45 mins ).

>>> 'nrc' problem from parrish -- Tue Mar 13 06:52:23 1990 <<<

problem:    vent cycle took 45 mins.

cause:      vent pressure set to low.

solution:   reset the nitrogen pressure to 5 psi. working pressure
            (the static pressure is 7 psi.) system is up.

>>> 'nrc' problem from hebert -- Wed Mar 14 15:15:17 1990 <<<

Burning phenolic smell after instability in current was
observed during evap of Au-Ge. The source select knob
does not turn as smoothly as before, reports XWu. There
is a sign that the souce select board got hot. I'm not
sure that this is where the problem is. The NRC should NOT be
used until the evap circuitry is checked out.

>>> 'nrc' problem from xwu -- Wed Mar 14 15:28:38 1990 <<<

during the evaporation, the burning smell came out, it seems
the filament selector has bad contact there (Au and Au/Ge, I
used).

I don't think nrc is usable before staff checks the problem
out.

xin

>>> 'nrc' problem from parrish -- Fri Mar 16 07:48:23 1990 <<<

system down for repair of electrode switching slector. 

>>> 'nrc' problem from parrish -- Tue Mar 20 11:04:18 1990 <<<

update:    All the burned parts has been remanufactured, and the copper
	   parts have been cleaned, reassembly of parts should be finished
	   today.   

           

>>> 'nrc' problem from parrish -- Wed Mar 21 09:34:00 1990 <<<

problem:    power supply smoking when turned on

cause:      switching mechanism loose, causing overheating of insulation
            board.

solution:   removed the switching mechanism board,mfg. new switching board
            cleaned all copper and brass parts and reinstalled the new
            board.note: because of the construction of the switching mech-
            anism the handle is fairly tight. system is up.

>>> 'nrc' problem from xwu -- Wed Mar 21 18:27:15 1990 <<<

the newly changed electrode switch board seems too tight, especially
not be able to turn to Zn position, could James pls to adjust it?

the nrc is still up, except Zn.

Xin

>>> 'nrc' problem from parrish -- Thu Mar 22 08:06:47 1990 <<<

problem:    switch board to tight,not able to turn to the Zn position

cause:      construction of the board makes it difficult to adjust tension
            without loosing good electrical contact.
            I put the board in reverse
solution:   removed the board and readjusted the tension,and reversed the
            board. tested the switching mechanism. all positions are avaliable
            and the tension is lighter.

>>> 'nrc' problem from prouty -- Mon Apr  9 18:26:45 1990 <<<

Crystal monitor 'xtal' light flashes on powerup.  Can get it to
go off by adjusting xtal holder.  Light will flash again if
power is cycled.

>>> 'nrc' fix from parrish -- Fri Apr 13 08:05:41 1990 <<<

problem:    `xtal light flashes on powerup

cause:       crystal monitor head loose

solution:    tighten head, light not flashing

>>> 'nrc' problem from xwu -- Fri Apr 20 12:13:32 1990 <<<

when i came to nrc, i found the cryo pump needs to be regenerated,
the temparature is within green zone.

xin

>>> 'nrc' problem from honglin -- Fri Apr 20 13:44:49 1990 <<<


The cryo pump need to be regenerated.

>>> 'nrc' fix from rnorman -- Fri Apr 20 14:21:00 1990 <<<

The cryo was pump/purge/pump for about 3 cycles.  Then at 40mt the hi-vac
valve was closed and the compressor turned on.  We have no idea how long
the cryo was off, but it was a least 3 hrs.  The cryo is chilling down now
and should be up for use at about 4:30 PM tonight.

>>> 'nrc' problem from xwu -- Wed Apr 25 12:43:29 1990 <<<

this morning about 11:40 when i came to nrc, i found that the cryo
pump was dumped again, the temperature is in green zone.
i turned off the comprasser and started to vent the cryo pump and
i'm going to regenerate it in about 2 hours.

could some one to investigate the reason?  i reported the similar
problem last friday.

xin

>>> 'nrc' problem from bob -- Thu Apr 26 09:34:08 1990 <<<

The cryopump on the nrc has failed and will need replacing. A spare
pump will be installed from stock on Monday, May 30th. The nrc is
down until then.
BOB

>>> 'nrc' problem from parrish -- Mon Apr 30 09:32:04 1990 <<<

update:   Cryo-pump change,a new array and absorber is being changed also
          at this time. the system should be back together tomorrow.

>>> 'nrc' fix from parrish -- Tue May  1 07:33:03 1990 <<<

problem:   cryo-pump failed

cause:     the mechanical parts appear to have a problem

solution:  removed the pump and replaced with a spare(this is not a rebuilt
           pump). system is up the pressure in the chamber is in the mid 7 
           range.
