[John Bennett]

Problem with power supply (red LD2 on, explained on previous post). Have had help from other members and have narrowed down to power supply as start point.Talked to Fanuc to get maint. manual (B-51695E) and was told it was only $18.00....great, but back-ordered for 8 to 10 weeks. Does anyone have a schematic of the power supply board for this control that they can send, so I can start investigating,and/or another supply route for this manual.

[sld4121]

Only $18 from Fanuc - either that is a typo, or it must be about 20 pages - lol.
Seriously though - did you ask Fanuc if they could send you a .pdf of that info? I know with the newer stuff, they are pretty decent about sending out info at N/C.

[John Bennett]

Maybe on newer stuff, but they will not send out PDF even if prepaid and the manual is just under 200 pages. They really make it hard to repair a very old control when they say 8 -10 weeks and no other option is given. I still hope that someone has at least has the schematics for the power board to start.

[Dan Fritz]

John,

I scanned some pages from my Fanuc 5T-2 schematics. There were two different power supplies used. One was a board numbered A20B-0005-0450, the other was a bunch of descrete components on an assembly A14B-0028-B001. If you have the board, then the schematics posted should be correct. I posted 4 scan file (.XPS graphic format) on my website, which you should be able to view with Internet Explorer. They are:

http://www.sub-soft.com/download/scan1.xps
http://www.sub-soft.com/download/scan2.xps
http://www.sub-soft.com/download/scan3.xps
http://www.sub-soft.com/download/scan4.xps

The scan1.xps file shows a block diagram of the transformers, the fuses, and a dotted-line outline which represents the A20B-0005-0450 board.

The scan4.xps file is a parts list, and the scan2.xps file shows your LD2 LED right in the middle of the page. A weak spot on these power supplies are the zener diodes ZD3 and ZD4, which regulate the +5R (reference) power supply output. I would replace ZD3 with a new 6.2v zener diode first. They should have them at any electronics supply store.

Good luck,
Dan Fritz

[mirejiya]

If you are ONLY driving a non-tacho vehicle (3,500kg), there is no legal requirement to use it, even if one is fitted.

[jolulank]

Dan,

You said you would replace ZD3 with a new 6.2v zener diode first. Is ZD4 a 6.2v zenner diode too?

Thanks

jolulank

John,

I scanned some pages from my Fanuc 5T-2 schematics. There were two different power supplies used. One was a board numbered A20B-0005-0450, the other was a bunch of descrete components on an assembly A14B-0028-B001. If you have the board, then the schematics posted should be correct. I posted 4 scan file (.XPS graphic format) on my website, which you should be able to view with Internet Explorer. They are:

http://www.sub-soft.com/download/scan1.xps
http://www.sub-soft.com/download/scan2.xps
http://www.sub-soft.com/download/scan3.xps
http://www.sub-soft.com/download/scan4.xps

The scan1.xps file shows a block diagram of the transformers, the fuses, and a dotted-line outline which represents the A20B-0005-0450 board.

The scan4.xps file is a parts list, and the scan2.xps file shows your LD2 LED right in the middle of the page. A weak spot on these power supplies are the zener diodes ZD3 and ZD4, which regulate the +5R (reference) power supply output. I would replace ZD3 with a new 6.2v zener diode first. They should have them at any electronics supply store.

Good luck,
Dan Fritz

[joyee]

If you are ONLY driving a non-tacho vehicle (3,500kg), there is no legal requirement to use it, even if one is fitted.

Yes I agree with you...Good information regarding non-tacho vehicles....