Polar 66 Irregular Knife movement

Morning all,
Our polar 66 has developed a fault over past couple of days. On first using or returning after short break the knife seems reluctanct to travel on pressing cut buttons. It cuts but seems laboured. Once a couple of cuts are done it seems to be more direct in the movement, anyone throw some light on this?
ta
colin

 

Hi sir:
Please review this 3 steps:
1) in the board Cutting circuit SK 95 see it:
Yellow Led: Cut Buttons : B28A N.C V73 -ON + B28B N.C v74-ON
Red Led ; " " N.O V75-OFF + " N.O V76-OFF
RED LED ; V86 Normally -OFF . When cut buttons actuated correctly(o.5seg) will be ON !!

2)Yellow Ved v71 SB- Simulator (k1M) See his schematic in resting position = ON
" ' v72 SB " (wsk) Polling =OFF
" " V77 kNIFE Upstroke(BDC Upstroke) from SAP 66 =OFF
" " V78 kNIFE Descending(BDCU neg.) from SAP 66 =ON

3) Finally the knife movement is transferred to the MHS95/66 Unit by a cable pulley againsta flat spiral spring prestress.
The correct mechanical adjusting for knife control Upstroke is performed by vertically shifting the complete unit.

 

will check, thanks for response
Colin

 

Fix it ?