Ok, now for the fun one. Fluke 8200A mode/function and/or range switch repair. As bitseeker suggested, dismantling and cleaning the switches is pretty easy. Easy like replacing the pilot bearing in a car with a manual transmission is easy. Once you get there, it should be cake - the getting there part is the issue...
To begin with, the meter must be torn down to the point that the display board/interconnect board assembly is out and in your hands, and from there the display board must be dismounted from the interconnect board, as it sits directly above the switch gangs. I'd suggest securing them to one another somehow (such as the method using plastic tie straps as shown in my earlier post) to make handling them easier and reduce chances of damage due to movement between them.
Interconnect/display assembly with display board secured out of the way of ganged switches on interconnect board:
The RANGE switch (on the right) may be worked on at this point as it is accessible, however if the FUNCTION switch gang (Vdc, Vac, ohms, etc.) needs attention, then the additional step of removing the function indicator PCB atop these switches must also take place. At a glance, this doesn't look like it should be too terribly difficult to do, as it is a single sided board (no through hole plating to worry about) and there are only 14 connections to deal with. A solder sucker and/or solder wick should permit removal to be accomplished with a minimum of foul language and hair loss.
Function indicator daughter card. Desolder switch connections (in rows, front to back - do not desolder indicators or resistors). Older versions will likely look at least somewhat different as they may be incandescent (most likely) or neon, rather than LEDs. Regardless, removal should be the same:
Once access to the switches has been obtained, the rear support bar must be removed from whichever gang of switches is to be repaired. The support bar is a three sided aluminum channel that is affixed to the switches by a combination of 'L' shaped slots that engage posts on the switch bodies and retaining tabs that are bent inwards and bear against the switch body sides, preventing the bar from shifting laterally and disengaging from the posts:
Front and rear support bars (range switches shown here):
Support bar and switch parts (range switch):
This image of the range switch as an error in the markup; the small top left tab is NOT a locking tab - they are on the bottom of the rear bar on the range switch:
Support bar on function switch assembly:
First off, prior to removing the support bar, ALL of the switches in the gang must be in the off (out) position, as when they are on, the rear of the actuator extends out through the support bar. Pushing a different switch in far enough to release the 'on' one, but not far enough to latch it will accomplish this.
The rear support bar is removed by carefully bending the locking tabs flat with the face of the bar so that they will clear the switch bodies (there are multiple locking tabs, likely one between each switch). On the range switch assembly, they are on the bottom, closest to the interconnect board, and on the function switch assembly they are on the top. Once the tabs are bent flat, the support bar is slid in the appropriate direction (towards the outside of the unit, to the right for the range switch and to the left for the function switch) far enough to permit the retaining posts to disengage from the 'L' slots that they are in. It is then removed by pushing it to the rear. I have not taken a meter apart this far, so I cannot comment on the force needed to move and remove the support bar, but would not be surprised if gently prying with a screwdriver in one of the slots is needed. If the bar is reluctant to move, recheck to ensure that all the tabs are bent clear of the switch sides.
Beyond this, the procedure shown in the following manual page photos should be followed to disassemble and clean the switches, and then reassemble everything. The gist of it is that once the rear support bar is off, the buttons, retaining clips, and springs are removed, then the actuator and contacts may be pushed out through the rear of the housing. The contacts are cleaned and the mechanism relubricated, then the whole mess goes back together. I have no idea what a modern equivalent to their suggested grease might be, but I would use a small amount of white lithium grease if I were doing it. Key being small amount, not a huge glob.
First page -
Sections 4-20, 21, 22, and 23 apply to ALL switches in the unit. Note that section 4-24 applies only to the 'function' switches (for extra confusion, there are two sets of 'function' switches) on the small daughter board that has the AC mains switch on it. These are push on - push off switches, NOT the ganged switches used in the 'function' and range assemblies we're interested in here.
Second page -
Figure 4-2 applies to the push on push off switches, NOT the ones we're interested in. I believe that 4-3 shows something similar ot what our switches will look like internally, but am not 100% certain. Our part starts at section 4-25:
Third page -
Now we're getting into the meat of the procedure. the illustrations combined with the picures above should hopefully make the procedure clear:
Fourth page -
Hopefully section 4-26 or 27 will not be necessary, especially as I've no idea where one might find a replacement switch...:
Fifth page -
The remaining instructions on installing a replacement switch:
\]
And as always, assembly is the reverse of disassembly.
Hopefully this helps - good luck with it, and let me know if I can try to dig anything else out to assist.
-Pat
<edit to add note about ensuring all switches are 'off' before attempting to remove rear support bar>
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