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Fig 3. Close up photo showing cracked solder connections  

 

 

DigiKey carries low ESR replacement capacitors (Nichicon FC Series):

 

Ref Existing 

Value recommended 

alternative DigiKey-p/n 

C8 56µF/50V 

 

P10322-ND 

C9 220µF/16V 

220uF/35V 

P10297-ND 

C12,C25 1µF/50V 

 

P10312-ND 

C21,C22 1000µF/25V 

2700µF/25V 

P10286-ND 

C26 680µF/35V 

1000µF/35V 

P10305-ND 

R17,R18*  33ohm, 2W 

33ohm, 5W, 1% 

45F33RE-ND 

FAN* 

n/a 

6.8CFM (w/o zener) 

CR015-ND 

Zener* 

n/a 

5.1V, for fan speed reduction  1N4733AFSCT-ND 

Table 1. Replacement Component list (* = optional items) 

Step #4 – Optional Cooling Fan Installation 
You can also install a 12V fan 40x40x10 mm inside the perforated box to reduce the component temperature 
and improve their lifetime; DigiKey p/n: CR015-ND

 

 

You may install the fan in the middle of the PCB long side on the perforated cover - see pics.  Test for 
sufficient room between the fan and inside PCB components.

 

Summary of Contents for FT-736R

Page 1: ...with a defective ESR of 450 ohms or more and C12 1uF 50V with a defective ESR of 60 ohms or more There are likely other capacitors that are suffering from similar aging problems Step 1 Remove the PSU from the main frame and disassemble the unit a unplug the AC cord b remove the radio s bottom cover c remove the 3 long M3 screws from the back securing the PSU heat sink bridge plate to rear chassis ...

Page 2: ...ad instead coil it so that it can dissipate some of the heat from the resistor wrap it around a drill bit to coil it c Re solder with fresh solder and flux all the cracked or cold solder connections on the PCB especially around the transformer d Remove solder splashes and possible solder bridges with brush carefully e Reinstall the base plate cage and secure the unit in place in the chassis and te...

Page 3: ...ND R17 R18 33ohm 2W 33ohm 5W 1 45F33RE ND FAN n a 6 8CFM w o zener CR015 ND Zener n a 5 1V for fan speed reduction 1N4733AFSCT ND Table 1 Replacement Component list optional items Step 4 Optional Cooling Fan Installation You can also install a 12V fan 40x40x10 mm inside the perforated box to reduce the component temperature and improve their lifetime DigiKey p n CR015 ND You may install the fan in...

Page 4: ...Fig 4 Modified cover with two oval shaped holes for the fan These holes were enlarged up to 3 8 mm before filing them into an oval shape Fig 5 Fan with 2 x 3 5 mm screws ...

Page 5: ...Fig 6 Fan at site wires are cut 12 cm from fan Fig 7 A 5V 1W zener diode plus a piece of shrink tube are added to the minus wire the fan speed is reduced to improve lifetime and reduce noise ...

Page 6: ...Fig 8 The wire and diode is ready to insert the PCB holes and solder Fig 9 Notice where and how the wire and diode are inserted into the PCB ...

Page 7: ...wing the fan through the perforation Fig 11 Completed power supply ready to install into FT 736R Be sure to roll and shake the unit to check for any loose parts inside Remove any objects that do not belong there ...

Page 8: ...DL7VHF s FT 736R Power Supply Schematic ...

Page 9: ...DL7VHF s Modified FT 736R Power Supply Schematic ...

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