MIL-PRF-28776F
3.5.7.4 Solder dip (retinning) leads. The manufacturer may solder dip/retin the leads of product supplied to this
specification provided the solder dip process has been approved by the qualifying activity.
3.5.7.4.1 Qualifying activity approval. Approval of the solder dip process will be based on one of the following
options (Note: Solder dip of gold-plated plug-in leads is not allowed.) All visual examination criteria shall be in
accordance with method 208 of MIL-STD-202:
a.
When the original lead finish qualified was hot solder dip lead finish 52 of MIL-STD-1276 (The 200-
microinch thickness is not applicable). The manufacturer shall use the same solder dip process for
retinning as is used in the original manufacture of the product.
b.
When the lead originally qualified was not hot solder dip lead finish 52 as prescribed above, approval for the
process to be used for solder dip shall be based on the following test procedure:
(1)
Six samples for each style and lead finish are subjected to the manufacturer's solder dip process.
Following the solder dip process, the relays shall be subjected to groups A2 and A4.
(2)
Three of the six samples are then subjected to the solderability test (see 3.8). No visual defects are
allowed.
(3)
Remaining three samples are subjected to the resistance to solder heat test (see 3.20).
(4)
All six samples shall be subjected to groups A2 and A4 inspections. Minor scratching of the terminals
due to insertion into test sockets shall not be cause for rejection.
3.5.7.4.2 Solder dip/retinning options. The manufacturer may solder dip/retin as follows:
a.
After the 100 percent A1 screening test but before the A2 electrical tests.
b.
As a corrective action, if the lot fails the A3 solderability test. Following the solder dip/retinning process of
paragraph 4.7.2.2.2.2, as a minimum, insulation resistance (all terminals to case) shall be tested, and the
A4 tests shall be performed, as applicable.
c.
For relays that have been subjected to and passed group A inspections. Following the solder dip/retinning
process, as a minimum, the insulation resistance (all terminals to case) shall be tested, and the solder
coating coverage and workmanship shall be visually examined. Minor scratching of the terminals due to
insertion into test sockets shall not be cause for rejection.
3.5.8 Diodes. Relays supplied with diodes installed internally are not considered electrostatic discharge (ESD)
sensitive. However, the diode may be ESD sensitive when not part of the coil circuit or wired internal to the coil. In
such case, the diode shall be processed in accordance with the requirements specified in 4.2.3. Manufacturers may,
at their option, test diodes used internally as specified in method 3015 of MIL-STD-883 modified to 16,000 volts to
eliminate the need for the ESDS protection program described above.
3.6 In-process inspection (see 4.7.1).
3.6.1 Solid state devices and diode in-process screening (see 4.7.1.1). Perform in-process screening as specified
in 4.7.1.1.
3.7 Screening (see 4.8.2). The contact miss detectors monitoring level shall be less than 100 ohms for relays
tested during cycling. Unless otherwise specified (see 3.1), any relay shall have a final insulation resistance
measurement of 10,000 megohms or greater.
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