Alfa IN alfin 281 w Service Manual Download Page 19

281 T / 281 W 

Ultima modifica/Last Update: 18/03/2008 Rev0                                                                                                             pagina 13 di 

17 

PROBLEM 

CASE 

SOLUTION 

The output voltage in 
MMA/TIG is zero and 
the welding procedure 
is blocked in MMA. 

 
 

 

Transils on the snubber board 0065 are 
damaged. 

 
 

 

ISOTOP diodes are in short circuit. 

 
 

 

The inductive value of the Power Trans-
former is null. 

Switch off the machine and disconnect the 
plug. Remove the snubber board ( above the 
ISOTOP diodes): 

!

check with a diode tester the status of the 
transils on the snubber board. If it’s dam-
aged, it must be replaced (picture 2); 

!

check with a diode tester the status of the 
diodes. If they are damaged, they must be 
replaced  (picture 2); 

!

Otherwise the Power Transformer could be 
damaged, then it must be replaced. 

The MMA welding is 
non optimal. 

 

Spattering occurs during  MMA welding.  

!

Make sure welding polarity is correct, the 
earth clamp is fixed correctly and check 
the hot-start and arc-force values that have 
to be decreased if they are too high.

 

When welding  the pro-
tection devices of the 
line set off. 

Make sure the welding current does not re-
quire  greater  power  than  the  one  supplied 
by the line.   

Decrease the welding current.

 

The remote control 
doesn’t work. 

 

Make  sure  the  wiring  which  goes  to  the 
front panel board is connected. 

 

Check the continuity of the remote con-
trol cable. 

 
 

 

The torch potentiometer could be dam-
aged. 

 

 

The military connector is damaged or 
disconnected. 

!

Insert  the  wires  into  the  connectors  cor-
rectly  and  insert  the  connectors  into  their 
housings. Should this not be sufficient, re-
place  the  front  panel  board  or  the  power 
board. 

 

!

The potentiometer must be replaced. 

 
 

!

Connect the military connector or replace 
it. 

The machine does not 
strike in HF mode.

 

 

The front panel could be damaged. 

 

 

The HF board could be damaged. 

 

HF board cable could be damaged or 
disconnected. 

!

Replace the front panel board; first verify 
that the spare part has the right software.  

!

The HF board must be replaced. 

!

Connect the cables or, if damaged, replace 
them. 

Gas comes out  but the 
machine doesn’t weld. 

Pre-gas settings are not correct. 

Regulate pre-gas settings. 

Summary of Contents for alfin 281 w

Page 1: ...OR NEPOU VEJTE STLA EN VZDUCH O P LI VYSOK M TLAKU ABY NEDO LO K MECHANICK MU PO KOZEN ELEKTROSOU STEK Ka d 4 m s ce zkontrolujte dn stav sva ovac ch kabel a s ov ch kabel NOTE Only trained personnel...

Page 2: ...sund n m krytu ze stroje po odpojen ze s t po dobu minim ln 5 minut kdy klesne nap t na kondenz torech na hodnotu pod 36 V No modification of any type may be made to the welding machine For safety whi...

Page 3: ...MG057 2 SERVISN MANU L SERVICE MANUAL ALFIN 281 W page 3 ALFA IN a s SERVISN TECHNICK DOKUMENTACE...

Page 4: ...MG057 2 SERVISN MANU L SERVICE MANUAL ALFIN 281 W page 4 ALFA IN a s SERVISN TECHNICK DOKUMENTACE Sch ma zapojen DOV ALFIN 281 W ELECTRICAL PRINCIPLE DOV ALFIN 281 W 3 N HRADN D LY SPARE PARTS...

Page 5: ...MG057 2 SERVISN MANU L SERVICE MANUAL ALFIN 281 W page 5 ALFA IN a s SERVISN TECHNICK DOKUMENTACE...

Page 6: ...p ipojen plynu 021 0000 0001 16 Konektor ovl dac 021 0004 3360 17 PCB konektor ovl dac 050 0001 0042 18 P edn elo 012 0004 0000 19 PCB v stupn filtr 050 0001 0031 20 No ky 016 0009 0001 21 Trafo 042 0...

Page 7: ...L SERVICE MANUAL ALFIN 281 W page 7 ALFA IN a s SERVISN TECHNICK DOKUMENTACE 39 Toroidn trafo 041 0005 0005 40 Vrchn dr k 010 0004 0001 41 Stojky 016 0010 0001 42 S ov filtr 050 0001 0039 43 PCB HF 05...

Page 8: ...NUAL ALFIN 281 W page 8 ALFA IN a s SERVISN TECHNICK DOKUMENTACE Poz S N CODE N zev 1 011 0012 0022 Kryt 2 003 0003 0002 N dr ka 3 011 0012 0004 Dr k 4 003 0003 0003 Chladi 5 011 0012 0003 Dr k ventil...

Page 9: ...o n dr ky 22 017 0003 1005 Z tka 4 Z VADY E EN Po Z vada P ina e en LED nebo jej p ipojen je vadn Opravte p ipojen nebo vym te LED po 13 1 Stroj je zapnut ventil tor funguje LED zapnut nesv t Silov PC...

Page 10: ...troda Vym te elektrodu Nahn te elektrodu proti sm ru magnetick ho vlivu 10 Nestabiln oblouk Vliv magnetismu Zm te pozici zemn c ho kabelu nebo p idejte zemn c kabel na opa nou stranu sva ence P eh t S...

Page 11: ...be adjusted The welding current potentiometer in the front panel connection not so good or damaged Repair or change the potentiometer The welding current adjusted too low Increase the welding current...

Page 12: ...jdou z PCB v stupn filtr k PCB d c jsou spojen a neporu en Obr zek 2 P ed kontrolou v stupn ch usm r ova odpojte v vody k PCB RC filtr ern a hn d dr t a zm te podle n sleduj c tabulky erven ern hodnot...

Page 13: ...r ova na silov desce Pro kontrolu m stku zm te tento podle n sleduj c tabulky testerem diod erven vodi ern vodi hodnota OL 0 7 ca Vykazuje li m en v t odchylky pro d kladn j kontrolu m te mezi p vodn...

Page 14: ...4 C A OL A B OL C B OL B A 0 4 B C 0 8 Hodnoty jsou orienta n Nam te li zkrat nebo rozpojen obvod OL je nutn PCB vym nit D le pou ijte tester pro zm en no i ek na zv t enin hodnoty mus b t v dy OL Ob...

Page 15: ...FA IN a s SERVISN TECHNICK DOKUMENTACE Obr zek 6 Pomocn transform tor p ipojen p es 10 vodi ov spojen s PCB silov Ujist te se e v stupy z transform toru jsou spr vn nainstalov ny tak jak je vid t na o...

Page 16: ...MG057 2 SERVISN MANU L SERVICE MANUAL ALFIN 281 W page 16 ALFA IN a s SERVISN TECHNICK DOKUMENTACE Obr zek 8 Digit ln multimetr OL ozna uje p eru en obvod...

Page 17: ...put and the varistors are not broken picture 5 If they are dam aged the line filter board 0068 must be re place picture 5 Otherwise check the power board Switch the machine off and disconnect the plug...

Page 18: ...replace it The Fan must be replaced The output voltage in MMA TIG is about 11V and the Machine does n t weld The wires that connect the output filter board 0031 to the front panel are not correctly i...

Page 19: ...d if they are too high When welding the pro tection devices of the line set off Make sure the welding current does not re quire greater power than the one supplied by the line Decrease the welding cur...

Page 20: ...nnec tor that goes to the front panel After that the solenoid valve or the front panel must be replaced picture 8 The front panel must be replaced The HF board must be replaced Should the operations c...

Page 21: ...y inserted To check diodes remove the snubber board and carry out the following measures with a diode tester At the ends of the two transils see below positioned on the snubber board OL must always be...

Page 22: ...ed To check the inverter carry out the following measure ments with a diode tester Should there be a short circuit on one of these measure ments or an OL instead of a numeric value the power board mus...

Page 23: ...of the short circuit is very high they become an open circuit The auxiliary transformer is connected by means of a 10 way connector to the power board Make sure the outputs of the transformer are conn...

Page 24: ...modifica Last Update 18 03 2008 Rev0 pagina 18 di 17 EXPLANATION Check continuity with a diode tester between points A B of the power board and x y poles of the connector that goes to the front panel...

Page 25: ...MG057 2 SERVISN MANU L SERVICE MANUAL ALFIN 281 W Vypracoval Worked out RL 23 6 2008 P ezkoumal Inspected DJ 20 4 2010 Schv lil Approved VS 20 4 2010...

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