Browse Prior Art Database

Process for Reclaiming Modules

IP.com Disclosure Number: IPCOM000095190D
Original Publication Date: 1965-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Ronkese, BJ: AUTHOR [+2]

Abstract

This process is utilized for reclaiming defective printed circuit modules having transistor chips and screened paste resistors.

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This is the abbreviated version, containing approximately 100% of the total text.

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Process for Reclaiming Modules

This process is utilized for reclaiming defective printed circuit modules having transistor chips and screened paste resistors.

The transistor chips are first removed by dipping the module substrate into hot solder. This increases the resistor values. The substrate is then immersed in hot silicone oil to reduce the values of the resistors. These can then be retrimmed by sandblasting to the desired values. The sequence of steps is as follows: 1. Immerse substrate into 100-40 flux. 2. Remove chips and crossovers by vibrating in 10-90 Sn-Pb solder at 590 degrees F for 10 seconds. 3. Dip substrate pins in 63-37 Sn-Pb for 10 sec. at 475 degrees F. 4. Clean substrate in hot perchlorethylene ultrasonically for 5 minutes and vapor degrease for 5 minutes. 5. Immerse substrate in silicone oil at 590 degrees F for 4 minutes. 6. Clean substrate in perchlorethylene ultrasonically for 1 minute, 3 times. Use new solution each time. 7. Repeat step 4. 8. Trim resistors to value. 9. Repeat step
4.

An alternate method is to eliminate the solder dip and utilize the hot silicone oil immersion for both removing the chips and reducing the resistor values.

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