Troubleshooting - Samsung SGH-600 Service Manual

5. Troubleshooting

5-1 Main Set
5-1-1 RX Sensitivity Problem
RX ON (RF Input - Frequency : CH Freq. + 20 kHz
U204 Input ≥ -60 dBm?
F200 Input ≥ -60 dBm?
Q200 pin 1 ≥ -65 dBm?
Q200 pin 3 ≥ -50 dBm?
F101 Input ≥ -50 dBm?
pin 4, 5 ≥ -50 dBm
pin 38, 39 ≥ -55 dBm
≥ -45 dBm (45MHz)?
pin 25, 26, 27, 28
Samsung Electronics
- RF Amplitude : - 50 dBm)
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
U102
No
Input (pin47, 48)
≥ -55 dBm?
Yes
No
U102 pin 42, 43
≥ -50 dBm?
Yes
F100
No
(225 MHz)?
Yes
U102
No
(225 MHz)?
Yes
No
U102 pin 36, 37
Yes
U102
No
30
mVp_p(20KHz)?
Yes
No
U411 pin 7, 14
1Vp_p(20KHz)?
Check U204, J401, C223
Solder Status k Resolder
Check U109, U204, C224, F200
Solder Status k Resolder
Check C219, L205, C217, C218, C216,
R219 Solder Status k Resolder
Q200, C216 Resolder or Replace
Check L207, L206, R221, C220, C170,
F101 Solder Status k Resolder
Resolder C172, L104, C171
Check U102 (pin 42, 43, 44, 47, 48),
R107, R109, C925, U839, C926, R504
Resolder or Change
Check C168, C167, C164, R137,
F100, C169, L108, L106, R138
Solder status k Resolder
Check C160, C159, C161, C162,
L105, L204 k Resolder or Charge
Check U102, C164, L161
Solder status k Resolder
Resolder or Check U102, C124,
L101, C119, R112 k Resolder
U411, C464, C445, L403, R466, L404,
R465, R462, R468, R443, R445, R444,
L401, L402, R447 k Resolder
5-1