PMCE Customer Service 1 X500 RF Trouble Shooting - Lesson Four

X500 Training Course

RF Trouble Shooting

PMCE Customer Service 2 X500 RF Trouble Shooting - Lesson Four

RF & TX Part

RF & Transmitter FieldRF & Transmitter Field

PMCE Customer Service 3 X500 RF Trouble Shooting - Lesson Four

Receiver Flow Chart

U501

F501&F502

U503

Rx

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Receiver Flow Chart

Rx : Set RF Measure Instrument: HP8960 or HP8922

1. Operating mode Test mode , Test function TW

2. 900/1800 Bend: Ch 62 947.4MHz , Cell power -60dBm (Ch699: 1842.6MHz)

3 850/1900 Band: Ch 189 881.4MHz , Cell power -60dBm (Ch661: 1.96GHz)

PMCE Customer Service 5 X500 RF Trouble Shooting - Lesson Four

GSM Receiver Placement

Comparison ListLOC. Parts Description

Step 2 C540 CERAMIC CAPACITOR 33pF 50V 0402

Step 3 C702 CERAMIC CAPACITOR 22pF 50V 0402

Step 4 L510 INDUCTOR 12nH 0402

Step 5 TP501 RXIP test point

TP502 RXIN test point

TP503 RXQP test point

TP504 RXQN test point

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Receiver Flow Chart

Step 1. Check JP1 first, if we don’t insert RF cable, pin 1 must short to pin 2Step 2. Use probe, touch C540 pin 1 : ~ -61dBm GSM Freq = 947.4MHz DCS Freq = 1842.6MHz

S1

S2

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C540 pin 1, GSM Freq = 947.4MHz

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C540 pin 1, DCS Freq = 1842.6MHz

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Receiver Flow Chart

Step 3. Use probe to touch C702 : ~ -61dBm (GSM Freq = 947.4MHz)

Use probe to touch C555 : ~ -61dBm (DCS Freq = 1842.6MHz)

S3 (DCS)

S3 (EGSM)

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C702, GSM Freq = 947.4MHz

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C555, DCS Freq = 1842.6MHz

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Receiver Flow Chart

Step 4. Use probe to touch L510 : ~ -63dBm (GSM Freq = 947.4MHz) Use probe to touch L513 : ~ -62dBm (DCS Freq = 1842.6MHz)

S4 (DCS)

S4 (EGSM)

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L510, GSM Freq = 947.4MHz

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L513, DCS Freq = 1842.6MHz

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Receiver Flow Chart

Step 5. Check RX I and Q signal , Use probe to touch U501, Pin 55 to 58.

S5

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U501, Pin 55 to 58, RX I and Q signal

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Transmitter Flow Chart

S2

S3, S4

U503

U501

U502

PMCE Customer Service 18 X500 RF Trouble Shooting - Lesson Four

Transmitter Flow Chart

1. Operating mode Test mode , Test function TW

2. 900/1800 Bend: Ch 62 902.4MHz, Cell power -60dBm, MS_TX_level 5 Ch 699 1747.6MHz, Cell power -60dBm, MS_TX_level 0

3. 850/1900 Band: Ch 189 881.4MHz, Cell power -60dBm, MS_TX_level 5 Ch 691 1.96GHz, Cell power -60dBm, MS_TX_level 0

TX : Set Transmitter Measure Instrument: HP8960 or HP8922 TX

PMCE Customer Service 19 X500 RF Trouble Shooting - Lesson Four

GSM Transmitter Placement

Comparison ListLOC. Parts Description

Step 1 R515 ROW RESISTOR 6.8K F 4P2R 0404

R516 ROW RESISTOR 6.8K F 4P2R 0404

Step 2 R526 FIXED RESISTOR 510 1/16W 0402

Step 3 R538 SPECIAL FIXED RESISTOR 39 1/16W 0402

Step 4 R546 FIXED RESISTOR 1K 1/16W 0402

PMCE Customer Service 20 X500 RF Trouble Shooting - Lesson Four

Transmitter Flow Chart Step 1. Check TX I and Q first. If TX I & Q, are not normal, this is mostly caused by G2, and in some minor cases by IOTA.

S1

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TX I & Q signal

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Transmitter Flow Chart Step 2. Use Oscilloscope probe to touch R526 : ~ 1.5V (for GSM) Use Oscilloscope probe to touch R526 : ~ 1.7V (for DCS)

S2

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R526 for GSM

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R526 for DCS

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Transmitter Flow Chart Step 3. Use probe to touch R538 : ~7 dBm, check PA_GSM_input (Freq = 902.4MHz) R540 : ~0 dBm, check PA_DCS_input (Freq = 1747.6MHz) If S2 and S3 are both ok, mean Transceiver is ok.)

S3 (EGSM)

S3 (DCS)

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R538 for GSM

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R540 for DCS

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Transmitter Flow Chart

Step 4. Press TX_APC(350), use Oscilloscope probe to touch R546 : ~ 0.8V, Then, press TX_APC(550), and touch R546 : ~ 1.3V

S4

Note:

APC controls PA output power. If PA has not enough power or no power, we must check S3 and S4. When APC is increased,the voltage of S4 will be increased as well. It means S4 is normal.

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R546 for TX_APC(350)

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R546 for TX_APC(550)

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DCS Receiver Placement

Comparison ListLOC. Parts Description

Step 2 C540 FIXED RESISTOR 18 1/16W 0402

Step 3 C555 FIXED RESISTOR 0 J 1/16W 0402

Step 4 C513 CERAMIC CAPACITOR 22pF 50V 0402

Step 5 TP501 RXIP test point

TP502 RXIN test point

TP503 RXQP test point

TP504 RXQN test point

PMCE Customer Service 32 X500 RF Trouble Shooting - Lesson Four

DCS Transmitter Placement

Comparison ListLOC. Parts Description

Step 1 R515 ROW RESISTOR 6.8K F 4P2R 0404

R516 ROW RESISTOR 6.8K F 4P2R 0404

Step 2 R526 FIXED RESISTOR 510 1/16W 0402

Step 3 R540 FIXED RESISTOR 18 1/16W 0402

Step 4 R546 FIXED RESISTOR 1K 1/16W 0402

PMCE Customer Service 33 X500 RF Trouble Shooting - Lesson Four

Any Questions?