Tajima 4 head 291 error

I bought an older used 4 head Tajima and we keep getting false thread break error 291. It will occur on different heads, different needles, etc. No consistency. My tech wants to replace all the tension springs. If it occurred on just one head I would agree but I have done a little research and found "Tension base card is faulty" as a possible cause. Has anyone else run into this and how hard would it be to fix? My tech is not very open to suggestions and basically told me I could trust him or not! Now I am thinking NOT.

Sylvia

now i think is more clear.
when the machine run 14 move up and down and hit 16
when 14 hit 16 close an electrical contact.

if the machine stop for false upper thead breakage means 14 is all the time in contact with 16(contact ON) because:
spring(14) force is to big
under 12 is rust
adjust spring force and clean the rust

if the machine DON T stop for upper thred breakage means 14 never make contact with 16(spring-14 force is to small) or 14 is mechanical in contact with16,but between 14 and 16 is fabric dust,temporary spray,etc.and electrical the contact is OFF
adjust spring force and clean 14 and 16

Attachment: 

I did a test sew out today. Here is what happened. I started with needle 1 (running all 4 heads). After sewing just a little while- error code 291, red light on head number one. I then went to needle 2, this time head 2 has red light but I restarted and it sewed fine for awhile but then red light again. Went to needle 3, head 2 red light and in fact head 2 had problems on almost all needles- 1-12. I turned head 2 off. On needle 7 I got 291 error on all heads. I tried turning off all but one head but again it would sew for awhile then 291, red light. I cannot narrow it down to any particular head or needle. I checked the connections in the back to what I think is the tension base card and also checked the connection to the main CPU but everything looks okay. I used compressed air, do not see any rust. I did not try doing anything with the springs or plates because it seemed to be happening on every needle and every head although never consistently.

I agree with George, it's almost always the spring to contact plate,so what I do is isolate 3 heads,sew on just one, go through one needle at a time until the error occurs,then unscrew the check plate just above the main tension assembly it's held on with a small silver Philips head screw. When you have this of look at the little tongue the part that the spring rests against when machine is at rest,I polish this with smooth emery cloth,lay cloth flat on table,press tongue flat down and move from side to side until oxidation is removed and there is an even shine ,then replace and set Philips screw in center of slot,then loosen 4 screws holding on the tension head .
on the back of the tension giving trouble you will see a small black slotted screw, Loosen this off and remove the assembly, I spray the pin and spring with wd40 then rub it all clean, also I jam a rag into the hole where the tension drops in and polish the brass section inside, then reassemble making sure the tension assembly is all the way down and adjust the check spring to medium response then tighten little black screw. I have my 10 year old does this when I am doing a full service, so once you've done one you just continue through each one..good luck

[SIGPIC][/SIGPIC]

for upper thread breakage the LED on tensione base is ON-red light
for UNDER thread breakage the LED flash red,but many,many times the panel display the same error 291.
the error for under thread breakage is 292 or 293

1.press F3 key until nr.2 is diplayed-UTC parameter
turn jog dial(the whils on panel right upper side) and select -(minus)
press SET.
now the under thread sensors are OFF.
make test.

2.let under thread sensors OFF
press F2 key until nr.5 is displayed-TD parameter.
turn jog dial and select max. value.(to turn OFF the sensors select -(minus)
press SET
make test

I am not at the shop right now but will check on Monday. I think it's a 1996 or 7. It has 4 heads, 12 needles. Maybe TMFX?

generaly for all Tajima machines with this kind of sistem for upper thread breakage(spring):

above the thread check spring is an plate.
between this plate and the spring is an electrical contact.
when the machine run this contact is ON-OFF,ON-OFF...and give this information to tension base card.
in case of thread breakage the spring don t move,cntact is ON and the machine stop.
if the spring force is to big and thread tension to lose the spring don t move and you will have false thread breakage.
to adjust spring force put an -screwdriver in the midle of button and turn right or left to increase or decrease spring force.
to be sure if the spring is the problem or not:

adjust the spring force.
take off the plate(above spring) and clean contact surface,and the back side plate surface
clean the metal part on tension base(where you put the plate fixing screw)
clean spring contact surface.
make test.
try for one head,one neadle first.

if not the spring is the problem:
clean with dry contact cleaner(spray)and compress air:
tennsion base card connector,cable connectors between tension base card and the back side of the machine.
cable from tension base goes in to an joint card.
clean joint card connectors.

if don t work maibe is necessary to make machine reconfiguration or to install again software.(considering all cards OK)
but about this tommorow, now is to late(1 AM)

is an seting for thread breakage stitches number.
i don t remember if is at F1,F2 or F3
find TD parameter,turn jog dial and set to maximum.press SET
make test.
if the machine has old software,max. value is 2
if is newer is 9

i forgot
the spring is fixed by button shaft.
take off button assy.
if in the tension base shaft hole is rust,also you will have false thread breakage.
clean the rust.

Thanks for trying to help DGeorge. I am afraid I did not understand most of it. I did try and check the connectors to the tension base card and blew out some dust with compressed air. I am going to do a total sample sew out tomorrow with all heads and all needles and try and isolate the problem. Today some needles on head 1 sewed fine others gave te 291 error. Head 2 seemd to do okay but I noticed one needle was not threaded and I did not get the thrad breakage warning so that is another problem. Could be that multiple thread sensors are acting up but according to the previous owner everything was fine before the move.

sorry if my english is not OK
if some needles work ok and some not i am sure not the cards is the problem.
is contact between spring and plate above.
clean first with compress air spring and around.
adjust the spring force
if in case of thread breakage the spring don t hit the plate above the machine don t stop

sgosline wrote:
I did a test sew out today. Here is what happened. I started with needle 1 (running all 4 heads). After sewing just a little while- error code 291, red light on head number one. I then went to needle 2, this time head 2 has red light but I restarted and it sewed fine for awhile but then red light again. Went to needle 3, head 2 red light and in fact head 2 had problems on almost all needles- 1-12. I turned head 2 off. On needle 7 I got 291 error on all heads. I tried turning off all but one head but again it would sew for awhile then 291, red light. I cannot narrow it down to any particular head or needle. I checked the connections in the back to what I think is the tension base card and also checked the connection to the main CPU but everything looks okay. I used compressed air, do not see any rust. I did not try doing anything with the springs or plates because it seemed to be happening on every needle and every head although never consistently.

reboot the sofware

[SIGPIC][/SIGPIC]