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FP-29 Yaesu Switching Power Supply Problem

WHen first applying AC, the two DC voltages (+30 and +13.8 VDC) try coming up but suddenly fall back to zero. Recycling power switch a few seconds later gives same results.

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Re: FP-29 Yaesu Switching Power Supply Problem

The power supply is running, but there is a failure in the protection circuitry. Usually a shorted Zener diode or small signal transistor. The Op-Amp for the current limiter can cause the same symptom.

If the supply does this ONLY with the radio connected, there is usually one or more shorted PA transistors.


Posted on Jul 21, 2011

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Pin Name Color Description
1 3.3V Orange +3.3 VDC
2 3.3V Orange +3.3 VDC
3 COM Black Ground
4 5V Red +5 VDC
5 COM Black Ground
6 5V Red +5 VDC
7 COM Black Ground
8 PWR_OK Gray Power Ok (is a status signal generated by the power supply to notify the computer that the DC operating voltages are within the ranges required for proper computer operation)
9 5VSB Purple +5 VDC Standby Voltage (max 10mA)
10 12V Yellow +12 VDC
11 3.3V Orange +3.3 VDC
12 -12V Blue -12 VDC
13 COM Black Ground
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15 COM Black Ground
16 COM Black Ground
17 COM Black Ground
18 -5V White -5 VDC
19 5V Red +5 VDC
20 5V Red +5 VDC

/PSON activated by pressing and releasing the power button while the power supply is in standby mode. Activating /PSON connects the power supply's /PSON input to ground, thereby switching the power supply to full-on condition.
18 AWG is recommended for all wires except pin 11, which should be 22 AWG. For 300W configurations 16 AWG is recommended.
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Hope this helps.
If this helps you resolve your problem, please
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