Cold testing method prevents formation of frost on printed circuit boards and part holders during testing at sub-zero temperatures. Freon permits rapid attainment of the required testing temperature

Cross, D. A.

Mc Neill, R. E.

English

NASA Technical Reports Server

April 1970
	
Brief 70-10172 
.
NASA TECH BRIEF	 - 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information-,Springfield, Virginia 2215 1., 
A Vapor Barrier for Cold Testing Printed Circuit Cards 
Printed Circuit Card 
Freon Vapor	 'I	 N'	 Connctors & Leads to \)4<Je Equipment 
Liquid Freon
I
	
	
" Sheet Metal Adapter to
Retain Freon Vapors 
1 1 T-
I I
	
.,-'	 Cold Chamber 
The Cold Chamber Arrangement forTesting Printed Circuit Cards 
is 
2. Requests for further information maybe directed ,
 to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B70-10172 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code GP, 
Washington, D.C. 20546. 
Source: Robert E. McNeill and Dan A. Cross of
The Boeing Company
under contract to

Marshall Space Flight Center 
(M FS- l51 15)
Category 01 
The innovation described in this Tech Brief is a 
method for preventing the formation of frost on 
printed circuit cards and part holders during cold 
testing at sub-zero temperatures. Previous methods 
required a dry box installed on top of the cold cham-
ber and the use of a dry gas under positive pressure. 
The figure illustrates an arrangement for testing the 
printed circuit cards. The freon permits rapid attain-
ment of the temperature required for testing the parts. 
The vapors from the liquid freon prevent the formation 
of frost on the portion of the card which does not re-
quire immersion in the freon. 
Notes: 
1. This innovation may be of interest to personnel 
engaged in testing electronic circuitry. 
., 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the Uniteçl States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights.
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A vapor barrier for cold testing printed circuit cards

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