Welch Allyn Micro Tymp 2, Service Manual

Page: 42 / 66

SECTION 7
Troubleshooting Guide for MicroTymp2 Handles: 11
MicroTymp2 Noise Test Procedure 13
1.
Introduction
In trouble shooting NEEDS CAL messages on the MicroTymp 2 there are two registers in the
EEPROM that are of interest - $AC (Historical Slave Error Register) and $AD (Historical Master
Error Register). Using either the CALVIN station or a printer, obtain a printout of the contents in
EEPROM. Most likely, if NEEDS CAL is displayed there will be a value other than $00 in either or
both of these two error registers. There are some special cases that cause the unit to display NEEDS
CAL while the contents of the two memory locations remains $00. These will be discussed later. To
understand how the error are indicated in the registers you must understand the binary and
hexadecimal number systems. The error codes are displayed in hexadecimal, however, the
individual errors are determined by converting these “HEX” numbers to binary and then looking up
the value in a table. This sounds confusing but it really isn’t that bad. I will give some examples later
on to illustrate my point. Below is a table that converts decimal to hex to binary numbers:
DEC HEX BINARY DEC HEX BINARY DEC HEX BINARY
0 $00 00000000 85 $55 01010101 170 $aa 10101010
1 $01 00000001 86 $56 01010110 171 $ab 10101011
2 $02 00000010 87 $57 01010111 172 $ac 10101100
3 $03 00000011 88 $58 01011000 173 $ad 10101101
4 $04 00000100 89 $59 01011001 174 $ae 10101110
5 $05 00000101 90 $5a 01011010 175 $af 10101111
6 $06 00000110 91 $5b 01011011 176 $b0 10110000
7 $07 00000111 92 $5c 01011100 177 $b1 10110001
8 $08 00001000 93 $5d 01011101 178 $b2 10110010
9 $09 00001001 94 $5e 01011110 179 $b3 10110011
10 $0a 00001010 95 $5f 01011111 180 $b4 10110100
11 $0b 00001011 96 $60 01100000 181 $b5 10110101
12 $0c 00001100 97 $61 01100001 182 $b6 10110110
13 $0d 00001101 98 $62 01100010 183 $b7 10110111
14 $0e 00001110 99 $63 01100011 184 $b8 10111000
15 $0f 00001111 100 $64 01100100 185 $b9 10111001
16 $10 00010000 101 $65 01100101 186 $ba 10111010
17 $11 00010001 102 $66 01100110 187 $bb 10111011
18 $12 00010010 103 $67 01100111 188 $bc 10111100
19 $13 00010011 104 $68 01101000 189 $bd 10111101
20 $14 00010100 105 $69 01101001 190 $be 10111110
21 $15 00010101 106 $6a 01101010 191 $bf 10111111
22 $16 00010110 107 $6b 01101011 192 $c0 11000000
23 $17 00010111 108 $6c 01101100 193 $c1 11000001
24 $18 00011000 109 $6d 01101101 194 $c2 11000010
25 $19 00011001 110 $6e 01101110 195 $c3 11000011
26 $1a 00011010 111 $6f 01101111 196 $c4 11000100
27 $1b 00011011 112 $70 01110000 197 $c5 11000101
28 $1c 00011100 113 $71 01110001 198 $c6 11000110
29 $1d 00011101 114 $72 01110010 199 $c7 11000111
30 $1e 00011110 115 $73 01110011 200 $c8 11001000
31 $1f 00011111 116 $74 01110100 201 $c9 11001001
32 $20 00100000 117 $75 01110101 202 $ca 11001010
33 $21 00100001 118 $76 01110110 203 $cb 11001011
34 $22 00100010 119 $77 01110111 204 $cc 11001100
35 $23 00100011 120 $78 01111000 205 $cd 11001101