From jdubeau@detec-rad.com Tue May 27 08:51:20 2003 Date: Mon, 26 May 2003 22:12:18 -0400 From: Jacques Dubeau To: Kirsten Sachs Subject: Re: heat seal X-IMAPbase: 1426689744 1 Status: O X-Status: X-Keywords: X-UID: 1 Hi Kristen, Sorry for the delay, weekends are crazy here. So here goes: To remove traces of the old heat seal: 1- from an installed readout board, pull off the shiny part of the heat seal. There may then be a yellow residue left on the readout and the circuit motherboard. The residue is the glue/epoxy of the heat seal. 2- clean off the residue with acetone. Beware of not putting acetone where you don't want it! z.B. silver epoxy etc... To install readout on another motherboard 0- turn on the heat seal press. Make sure that the set temperature point is at 250 C. You must toggle to switch on the ManuBond press, one position gives you the current blade temperature, the other one gives you the target temperature and the last position gives (I think) an alarm. 1- put the readout on the motherboard an centre vertically and horizontally as well as possible. In particular, make sure that the readout pads of the readout board and motherboard are well aligned. This is important as there is on average only 1-2 black traces of the heat sel that will join the pads. Tape the board in place with kapton tape along the sides 2- cut a piece of heat seal connector (transverse to the black strips) roughly 8 mm (in the direction of the black strips) and just a bit wider the readout pad array of the readout board (my guess, from memory, 5-7 cm wide). 3- lay down the piece of heat seal connector in place on the junction of the readout board and the motherboard. The shiny side of the heat seal connector should be facing away from the readout boards. The heat seal connector should not cover entirely the readout pads. It should leave just enough exposed metal to probe later with a pointy multimeter probe. 4- tape the heat seal connector in place with just little pieces of kapton at each extremity. We remove that tape later, so don't put too much of it. 5- we bond the heat seal on the part that is over the readout board first. We need to cover the heat seal with a strip of grey rubber. Align one of the edges of the grey rubber with the edge (on the readout board side) of the heat seal tape. Later, when the assembly is put below the pressure blade, the edge of the grey rubber strip will be your only reference of where the heat seal is. Tape the grey rubber in place (bit of kapon tape at the extremities, to be removed later). 6- when under the press, the motherboard must be supported from under, otherwise all the pressure will go on the output conncetors and the assembly will flex. I use a piece of reactangular aluminum that is usually lying around in the clean room. 7- slide the assembly under the blade, with the grey rubber edge facing you. Drop the heated blade near the rubber and line up the edge of the blade nearest you to the edge of the grey rubber strip. 8- when you are sure that the alignment is OK, bring the blade down until your pulling about 8-10 ft-lb of torque on the lever dial. Count slowly to 8 and release. 9- remove the grey rubber, check your work. If you are happy, proceed with other side. Remove also the pieces of kapton holding the heat seal connector down. Pull slowly, parallel to the board surface while holding the heat seal connector (otherwise everything comes off). 10- remove grey rubber strip and align it over heat seal with the other edge of the heat seal. 11- tape down the grey rubber. 12- this time, the blade has to slide between the edge of the readout circuit board and the surface mount components of the motherboard. Slide the assembly below the blade (critical edge facing you) and bring the blade down. 13- press the balde only when you are sure that it falls in the right place. Bring to 8-10 ft-lb for 8 seconds. After this, prode the continuity of every channel from readout board to the motherboard. If you read 1 Ohm or less, then it is OK. If you read 2-3 ohm, then you have not pressed enough or the blade was not hot enough. You then repeat the pressing stages and it should be OK. If you read open-circuit, then the black heat seal traces are cut (look with a magnifying lens) and you have to repeat everything. This is due to the blade pressing on the heat seal connector over the edge of the readout circuit board. That cuts the traces. I hope that all this is clear. Phone me tuesday to let me know how it went. Good luck. Jacques **************************************************************** Jacques Dubeau, Ph.D. President DETEC Radiation Effects Consultants Experts-conseil, effets du rayonnement nucléaire 920 Cook Road, Aylmer, Quebec, Canada, J9H 5C9 Tel: 819 685-0500, Fax: 819 685-9218 Web: www.detec-rad.com, email: jdubeau@detec-rad.com ****************************************************************