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HamCall (October 1991)
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ux_49.txt
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1990-10-14
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Model: UX-49A 900 series band unit REVISED 11-15-89
Division: Amateur
Note: This service bulletin is meant for technical per-
sonnel with experience working on solid state com-
munications equipment. Damage caused by im-
properly installing this modification may cause
ICOM to charge for subsequent repairs to the
product. ICOM does not warrant this modification.
Bulletin #: 8215-001
Date: August 2, 1988
Subject: Improve PLL lock up time
Information: The PLL lock up time on some units is not quick
enough for all types of receivers. The
problem may be worse when CTCSS is used.
Operation will appear near normal when
the UX-49A is operated in simples mode
with no CTCSS.
Procedure
1. Remove the top and bottom covers.
2. Remove the main board and replace the following components:
Current New ICOM
Part Part P/N
C87 .1uf 35 VDC tantalum 918-01670
C97 10uf 16 VDC tantalum 918-01679
R60 100 K 1/8 watt 915-01124
R49 2.2 K 1/8 watt 915-01105
3. Add a 2.2 uf 16 VDC tantalum (ICOM P/N 918-01674) from the
collector of Q15 (positive lead) to the adjacent ground
(toward the edge of the board).