User`s manual

Lake Shore MTD Series Cryotest System User’s Manual
3-8 Installation
3.11 HOW TO CHANGE THE TEST SET ASSEMBLY
This procedure is necessary when switching a Dual In-Line Package (DIP), Leadless Chip Carrier
(LCC), or other device that require a different fanout board and socket.
NOTE: The MTD-150 System should be stabilized at room temperature and the transfer line removed.
1. Follow Steps 1 thru 3 in Paragraph 3.10 – Changing the Fanout Board.
2. Remove the 4 gold plated posts which hold the cold pedestal in place.
CAUTION: Handle posts with care. They are made of gold plated aluminum and threads can be
easily damaged.
3. The cold pedestal may now be removed.
NOTE: It may be necessary to gently pry the cold pedestal base from the cold plate as the indium
foil at the thermal interface tends to stick to the mated surfaces.
4. Clean the cold plate surface where the cold pedestal will contact the cold plate with rubbing alcohol
and a paper wipe. Make sure that the cold pedestal base plate is also clean.
5. Cut pieces of 0.07 – 0.127 mm (0.003 – 0.005 inch) thick indium foil to the shape of the cold pedestal
base plate.
6. Fasten the cold pedestal to the cold plate (with the indium foil placed carefully between the
surfaces) using the 4 gold plated posts supplied with the test set assembly kit. Also, be sure to use
the Belleville spring washers.
CAUTION: Do not over tighten the posts and remember to handle with care.
7. Install the fanout board so that the cold pedestal protrudes through the device socket.
CAUTION: The cold pedestal and fanout board should not bind. Do not try to force the socket
over the cold pedestal.
8. Replace the fanout board retaining ring with the 4 phillips flathead screws.
9. Place the DUT in the device socket on the fanout board and ensure that its contacts line up with the
socket contacts.
10. Carefully place the chip carrier clamp assembly over the DUT and check that it compresses the
DUT into the socket without binding.
11. Replace the chip carrier clamp assembly mounting screws in a 1–2–3–4 sequence to ensure
uniform clamping pressure.
CAUTION: Do not over tighten mounting screws or completely tighten one at a time. Tighten
each screw one-half turn, continuously repeating the 1–2–3–4 sequence until all four
screws are snug.
12. Replace the cooled filter wheel assemblies, if used, and tighten the 3 captive screws and the drive
shaft collett lock hex nut. Ensure that the filters/apertures are properly aligned.
13. Replace the radiation shield.
14. Clamp down the vacuum chamber end closure.