[time-nuts] Fwd: HP5061B Ion Current
paulswedb at gmail.com
Wed Mar 29 11:15:00 EDT 2017
Very good and it is as I thought. No real magic a tough job.
Whats good about the suspended approach is it preserves the can nicely.
I have done a pry (small screw driver or xactor blade) and drip approach
and it actually slightly bends the can lip out.
I have never opened one of the HV supplies. But have had to open filters.
They can be put back together but never as nicely as the approach you are
using that should leave the can in optimal shape.
Thanks for sharing some very good insights.
Have you come up with a good 200 M replacement yet?
On Tue, Mar 28, 2017 at 5:37 PM, Donald E. Pauly <trojancowboy at gmail.com>
> 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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