[time-nuts] Fwd: HP5061B Ion Current
Donald E. Pauly
trojancowboy at gmail.com
Tue Mar 28 17:37:35 EDT 2017
We continue troubleshooting our 2nd HP5061 acquisition. The 200 Meg
resistor in the +3,500 V supply had gone way up in value and made it
appear that the supply was half normal voltage. See the black
resistor in http://gonascent.com/papers/hp/hp5061/3500top.jpg . We
installed a temporary resistor. The ion current was pegged when we
reinstalled the supply. This is not surprising since instrument has
been stored for over a year.
Here is the way that KB7APQ unsoldered the latest two high voltage
supplies. See http://gonascent.com/papers/hp/hp5061/desolder.jpg .
High Voltage Power Supply Unsoldering and Repair
1 - Suspend power supply on steel wires using 6-32 ground lugs and nuts.
2 - Heat solder joint evenly all the way around using a propane torch.
Be careful to avoid too much heat on connections. Act as quickly as
possible to avoid overheating components.
3 - Pull down firmly on outer can while wearing a welding glove.
Rotate unit until can comes away from power supply. Cold solder on the
inside of the can can prevent power supply from sliding all the way
out. You may want to shake off some excess solder as it melts.
4 - When can slides off of the power supply turn it over and tap it on
the floor to remove excess solder from the inside of the can.
5 - Mark can for mounting holes to be used to reattach outer can after
repair. I used 0.970 inches from the can side and 0.100 inches from
the open end. The off center 0.970 dimension is to avoid power supply
screws from interfering with each other in the event both power
supplies need this modification.
6 - Center punch where marked then insert power supply back into can.
Note the orientation for the label on top. Using a number 50 drill
bit, drill through both can and base.
7 - Tap holes in the base using a number 2-56 tap.
8 - Enlarge the holes in the outer can using a number 43 drill bit.
9 - Use 2-56 x 1/8" pan head screws to secure the outer can.
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