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10 

JAT-740 Angle Sander 

 

Troubleshooting JAT-740 Angle Sander

 

Any disassembly of the tool should be done by qualified service personnel. For problems not addressed 
below, contact JET technical service at 800-274-6846. 

Problem 

Possible cause 

Remedy 

Tool will not start. 

Air valve closed or obstructed. 

Open valve; clear any obstructions. 

Dirt or gum deposits on 
components. 

Flush tool with gum solvent. 
If problem persists, disassemble, 
clean and lubricate internal parts. 

Rotor vanes or other components 
are worn. 

Replace worn components. 
(Replace vanes as an entire set.) 

Trigger inoperable. 

Clean trigger mechanism to ensure 
free movement. Replace 
mechanism if needed. 

Bearing(s) worn. 

Disassemble and inspect bearing. 
Grease or replace as needed. 

Starts immediately when 
air is connected without 
throttle lever being 
pressed. 

Throttle lever malfunction. 

Clean throttle lever mechanism to 
ensure free movement. Replace 
mechanism if needed. 

Excessive or abnormal 
vibration. 

Bearings worn. 

Disassemble and inspect bearing. 
Grease or replace as needed. 

Loss of power; erratic 
action. 

Low air pressure. 

Verify compressor has proper CFM 
rating for tool. 
Check compressor regulator 
setting; set air pressure to 90 psi.   
Set regulator dial on tool to 
maximum setting. 
Check for loose connections.  

Moisture or obstruction in air 
hose. 

Air supply must be clean and dry. 
Clean out air hose(s) and remove 
any kinks or bends. 

Improper size of air transmission 
lines, hoses, fittings, or 
couplings. 

Use appropriate-sized air 
lines/hoses. 
Verify proper fittings/couplings. 

Dirt or gum deposits on 
components. 

Flush tool with gum solvent. 
Check and clean air filter on 
compressor.  
Clean external areas of tool. If 
problem persists, disassemble, 
clean and lubricate internal parts. 

Rotor vanes are worn. 

Replace vanes (entire set). 

Excessive heat develops 
in tool. 

Insufficient lubrication. 

Lubricate with air tool oil. 

Worn components. 

Replace components as needed. 

Severe air leakage. 
(Note: Minimal escape of 
air is often normal for air 
tools.) 

Air valve obstructed or damaged. 

Clean or replace. 

Housing loose or damaged. 

Tighten or replace as needed. 

Summary of Contents for 505740

Page 1: ...Pneumatic 7in Angle Sander 505740 JAT 740 Operation Parts Manual M 505740 Edition 2 06 2015 JET 427 New Sanford Road LaVergne TN 37086 Ph 800 274 6848 www jettools com Copyright 2015 JET...

Page 2: ...any additional action needed JET has Authorized Service Centers located throughout the United States For the name of an Authorized Service Center in your area call 1 800 274 6846 or use the Service Ce...

Page 3: ...romium from chemically treated lumber Your risk of exposure varies depending on how often you do this type of work To reduce your exposure to these chemicals work in a well ventilated area and work wi...

Page 4: ...er accessories may be hazardous 31 Maintain tools with care Keep air tool clean and oiled for best and safest performance 32 Do not use combustible gases carbon dioxide oxygen or any bottled gas as an...

Page 5: ...this document The instructions and warnings in this manual may not encompass all possible workplace environments The operator is expected to take appropriate precautions and exercise common sense As...

Page 6: ...verall Length 12 in 304 8 mm Housing material Aluminum with rubber grip Net weight 4 72 lb 2 14 kg Shipping weight 5 39 lb 2 44 kg 1 The specified values are emission levels and are not necessarily to...

Page 7: ...o the tool is not recommended as vibration may cause the connection to fail Instead add a leader hose and install any quick change couplings farther down the line 8 Grip handle firmly and place other...

Page 8: ...ool for the job Poor maintenance practices such as using excessive air pressure or air volume Improper or no lubrication Rule of Thumb If it takes more than 8 seconds to tighten or loosen a bolt or nu...

Page 9: ...the environment Your tool contains materials which can be recovered or recycled When its useful life has expired please leave tool at a specialized facility Figure 2 Recommended arrangement of air pip...

Page 10: ...al vibration Bearings worn Disassemble and inspect bearing Grease or replace as needed Loss of power erratic action Low air pressure Verify compressor has proper CFM rating for tool Check compressor r...

Page 11: ...following pages To order parts or reach our service department call 1 800 274 6848 Monday through Friday 8 00 a m to 5 00 p m CST Please have the stock number and serial number of your tool available...

Page 12: ...gle Sander 505740 JAT 740 7in Angle Sander exploded view 44 28 23 32 43 4 5 30 26 25 31 24 29 23 13 12 12 13 15 12 2 3 13 10 7 11 6 8 9 13 12 38 16 14 1 33 27 20 17 22 21 18 19 23 37 36 35 45 46 40 41...

Page 13: ...12L 1 23 BB 608ZZ Ball bearing 608ZZ 3 24 JAT741 24 Spindle 5 8 11 1 Index Part No Description Qty 25 JAT741 25 Retaining ring STW 16 1 26 JAT741 26 Wave washer WW 16 1 27 JAT740 27 Pinion gear 1 28 J...

Page 14: ...14 JAT 740 Angle Sander This page intentionally left blank...

Page 15: ...JET 15 This page intentionally left blank...

Page 16: ...16 JAT 740 Angle Sander 427 New Sanford Road LaVergne Tennessee 37086 Phone 800 274 6848 www jettools com...

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