SB-600 with zoom problem

NateW

Hi all-

Got a question, and I've struggled for an answer for a little while with no luck on googling it so far.

My SB-600 was working great, then at some point I realized it wasn't zooming (little "--" on the screen) and soon after realized it zoomed back and forth on start-up trying to figure out where it was. When it finally failed out, it would sit somewhere toward full zoom and just be happy there and otherwise function perfectly.

I don't think it got bonked, but that's a possibility. Since I've now got it in pieces on the dinning room table (and have to move it, a 5yo and 7yo around will not accommodate long term resting on the table), I've found it (initially) looks like everything's OK. Contacts on the zoom position sensor look OK, though a bit dirty. Since the zoom was functioning before I took it apart (based on motion feel), I bet it moves back and forth OK.

My next thoughts are:
0.5) put the batteries back in and check the functionality with the lid off.
1) actually fully discharge the cap (ha. good timing, eh? though I've read it's something like 350V so not gonna kill anybody.)
2) finish the disassembly to get the motor out and away.
3) check the contacts (CAREFULLY) for the zoom position sensor.
4) put it all back together and hope it actually works now.

Any other (i.e.: better) suggestions?

Thanks!
Nate

NateW

NateW wrote:

My next thoughts are:
0.5) put the batteries back in and check the functionality with the lid off.
1) actually fully discharge the cap (ha. good timing, eh? though I've read it's something like 350V so not gonna kill anybody.)
2) finish the disassembly to get the motor out and away.
3) check the contacts (CAREFULLY) for the zoom position sensor.
4) put it all back together and hope it actually works now.

OMG. Taking my own advice worked wonders. Until now, I thought that was nigh on illegal!

I've discovered the motor appears to be physically unconnected to the screw it's supposed to drive. Though you only get a second or two to play during the boot up phase, I've not been able to make the gears engage yet.

So..... Now, I'm thinking that somehow a bracket holding the motor in place got broken and needs to be reconnected at the right spot to allow engagement. This next part of the disassembly could be tricky (I've only got the top of the top part off right now, the bottom looks to be the main mount point for all the internals).

Before I get worked up and actually start it, I thought I'd check in with people (this time with updated info) and see what the thoughts are.

Thanks again in advance!
Nate

ziggy53

Nate, be "extremely" careful with an open flash and potentially charged capacitor. It truly is a lethal device and especially so around children. The combination of voltage and current is more than enough to stop a heart and it can cause serious burns too. Proper discharge uses a large resistance and large capacity resistor. I won't describe the procedure because I'd rather you didn't try it.

angevin1

ziggy53 wrote:

Nate, be "extremely" careful with an open flash and potentially charged capacitor. It truly is a lethal device and especially so around children. The combination of voltage and current is more than enough to stop a heart and it can cause serious burns too. Proper discharge uses a large resistance and large capacity resistor. I won't describe the procedure because I'd rather you didn't try it.

I'm with Ziggy here...around kids is not good...And that capacitor does bite...

But I am unsure if you have a question here, or if you are answering them yourself. I've had my Sb600's apart to replace bulbs and so forth, so do you have a question..or do you see broken motor mounts?

NateW

angevin1 wrote:

I'm with Ziggy here...around kids is not good...And that capacitor does bite...

But I am unsure if you have a question here, or if you are answering them yourself. I've had my Sb600's apart to replace bulbs and so forth, so do you have a question..or do you see broken motor mounts?

In general, I'm totally with Ziggy and Angevin1: big capacitors and kids are a bad mix. Heck, any "capacitors and a lack of understanding" is a bad mix. My solution: 100K Ohm resistor (later reduced to 100 Ohm to speed things up if necessary) from the kids' electronics play set. Wonderful things. Being an engineer with at least a rudimentary knowledge of electronics doesn't hurt, either.
In agreement with all who've said it (or just thought it): do not do this without first understanding what you're going to be doing and then taking appropriate safety precautions (especially with kids around). Capacitors do hold charge and even if speed light ones aren't like TV or large studio strobe caps, they can still remind you they exist.


Really, I kind of answered my own question, but was more looking for anyone who has experience with mechanical repairs on speed lights. Google wasn't very expansive, so I was looking for others who may have actually been through something like this. If a specific question comes up, I'll have to ask it directly as the problems I'm having now seem to be more "I should try <something>" rather than "Help!"


So: what's gone on in the (admittedly few) hours since the last "record"?
I've had it apart; the motor mount is broken. Getting it fully, mechanically apart is one heck of a lot harder than replacing the bulb appears to be (as long as soldering is no issue to you). Since I've not done the bulb, I really couldn't say.
The "go-to-hell" ring* that holds the main bulb mount alignment shaft in place... well, it lives up to it's name. Worst I've played with yet, probably due to small size. Jewelers pliers helped and were the saving grace in the end (during replacement).
*the proper name, as my dad thought it appropriate for a roughly 10 year old to know. By college I learned everyone else called it a snap ring.

Super glue may or may not hold up, though I'm not confident. Putting it back together again (after a 2nd repair job) does not make me look to the future with glee.

I've now got it partially back apart enough (after it still wasn't able to move the flash bulb back and forth) and I think I need to re-grease it enough to reduce the required motor torque enough to allow this truly tiny motor to do its job. (Wiring/electronics appear to be fine still, just the motor needs less friction to work when installed.)

Any comments with experience for mechanical repairs on the SB-600 or related items would be appreciated.

Thank you!</something>

angevin1

After having one of those apart, I can't understand how the motor-mount broke. It is bolted in place at several places and is a little time consuming to remove. As with most repairs finding out why something broke is important, so as not to repeat it.

I would think that an epoxy glue would be required to handle the strain/torque of the motor itself. and that you'd have to remove it to effect a repair.

Good Luck~

NateW

Nikon replied to my email request for help with the Parts department's phone number. Parts faxed me (they don't email) an exploded diagram for the relevant part of the flash (I couldn't find this thing on line to save my life!). (Then they closed; 3pm Pacific comes early on Eastern time. I'll order the part tomorrow morning.)

Looks like the part I need is 1K682-870-1. I'm sure they'll have the grease I need, too.
Re: why it broke: no idea, but I suppose it might have been bonked. Since the area it broke is not really load bearing, I'm kinda at a loss, but it is definitely broken.
(gallery link for closer looks: http://www.ntwphotos.com/Other/SB-600-repairs/10859189_ZJ8pu/1/757612773_dii93)


If you look very closely at this next image, you can see a crack at the base of the motor mount. I used the worm drive as a support to keep the motor mount properly placed. (is the now smaller tolerance around the worm drive a source of increased friction? maybe.)



For those interested: (I know it's big even more than the rest of the post, but that's necessary to read the part numbers. Sorry if it's a problem for someone!)

ziggy53

WTG Nate.

time2smile

Great stuff to know

angevin1

Nice photos and follow thru!

I see the mount broke right where you'd expect it: At the boss for the inboard Motor-mount, it's weakest point.

Still, I wonder why it broke? getting dropped doesn't seem a likely explanation and you said you thought it didn't drop...so where besides a factory over-torqued screw could this have come from? Perhaps the "work" part of the assembly was stuck?

NateW

(Thanks for all the clappies! )

Re: overtorqued screw: given the method of mounting (small srew to plastic threads) and the loading potential of the mounting portion of the bracket, it seems unlikely that torque was the problem. Your point about an effectively locked work gear is well taken, though, especially given how hard the motor has to work to get it to turn now (basically impossible without assistance).

Once I get the new part and install it, I'll have to do a better as-installed review. I am still struggling with what could have caused enough load to break it like this. Had I taken a micro shot of the fracture before playing with it as much as I did, I might have been able to do a bit of amatuer FMEA on it (i.e.: check for "growth rings" of progressive fracture rings from fatigue failure). I have little enough experience/knowledge of this and the material that I don't put a lot of weight in my thought that the material is likely too soft to show this kind of telltale. Kind of a moot point at this stage, though...

Not that Nikon is particularly interested in telling us, but I wonder what kind of repair/compliant rates they have with this failure mode. Might also be interesting to know if the SD-900 (or even 800) have a similar motor bracket. When I get the new part(s), I plan to do some micro shots of them to look for obvious stress risers (like little/no filleting) in the transition from base mount to motor mount. If it's sharp enough, and the material is fatigue sensitive enough (and if the motor torque were high enough....), I can see (read rationalize ) where the failure could have come from a locked worm drive.

All of this aside: I'm just as glad that I posted the exploded view diagram here 'cuz I can't access personal email from work computers. I need the part number to call Nikon with!

(PS: another thought: maybe an unexpected preload from a not-quite-perfectly formed motor support bracket and head assembly bracket? If I don't stop now, I'll come up with potential causes all day!)

(edit: bracket: $0.90. Worm gear: $2.58. Ordered; we'll see how far we get when they're here!)

angevin1

I changed my mind.. Manf. Defect! The diagram shown while accurate, is truly deceiving since it is somewhat inverted, along with not showing all of the work. That said, The MM is actually firmly mounted to a base plate. Also the amount of torque required to move the worm is very small, And if you hit the zoom (powered up) with the cover off, you'll find the flash carrier skips until you let go.

So, Manuf. Defect is my vote~

Can't wait to hear your verdict~

NateW

I'm not sure of the real cause, and since I've destroyed the evidence by now (by gluing it back together!), I doubt I'll be able to tell for sure.

In the mean time, though, I suspect more images of the disassembled flash head may be in order:
Note the (very) small metal pin thing between the finger and the clear plastic "bearing" (next to the 4 little wire looking contacts). This is the thing that follows the worm gear and zooms the flash head.

the whole subassy without flash bulb holder or motor (and broken motor mount). The metal bar is not in it's assembled position, but is placed to show the locations of where it would go (not fully installed).

the whole thing assembled except the broken motor mount. If you look very closely, you can see the motor mount bracket mounting screw to the left of the green thing on the lamp assy. The screw head is half in shadow and almost looks to be being pointed at by a clear plastic flange roughly 1/2 way between the worm gear and the green thing. (The screw driver was turing the drive threads of the worm gear.)

Another view of the same assy

this time to show the front mounting screw of the worm gear/motor mount bracket.

Yet another view, this time pointing to the first screw. (why did I put things in this order? smugmug's crazy picture ordering, though I'm not sure why it's that order.)


Something more substantive regarding the repairs when the new parts get here.

NateW

(and now the motor bracket is on backorder....)

NateW

Parts made it here, finally!

After two harrowing experiences with almost losing a piece (one, a screw I might have done without, two the metallic piece that keeps the flash head following the worm drive...), it's back together and works perfectly!
In the end, I'm still not sure why the motor couldn't drive the screw, but it wasn't even able to do it when all it was driving was the screw. I've still got the parts, so if I need 'em, I may try lubrication to make it all work better.

I wonder if the motor has lost some torque ability, though; there was even a bit with the new parts where it couldn't move the screw with no other load. I forced the motor to turn (with a screwdriver on the face of the gear, not the teeth) in the hopes it was just a dead spot in the windings somehow. Dunno if that was it or not, but it's back together all the way and functioning now.

Next step in the evolution of the SB-600: an external power port!
I've got the base apart, but the packaging in there is nearly rediculous it's so tight. I still think there's a way for me to do it, I just need to study it a bit more first.

If anyone's heard of a solution/method for this aspect, I'd love to hear it....:D

Thanks everyone for your help with the zoom issue.
I'm glad that part's over!
(For now............ Buwahahahaha!!!)

Nate

angevin1

NateW wrote:

Parts made it here, finally!

After two harrowing experiences with almost losing a piece (one, a screw I might have done without, two the metallic piece that keeps the flash head following the worm drive...), it's back together and works perfectly!
In the end, I'm still not sure why the motor couldn't drive the screw, but it wasn't even able to do it when all it was driving was the screw. I've still got the parts, so if I need 'em, I may try lubrication to make it all work better.

I wonder if the motor has lost some torque ability, though; there was even a bit with the new parts where it couldn't move the screw with no other load. I forced the motor to turn (with a screwdriver on the face of the gear, not the teeth) in the hopes it was just a dead spot in the windings somehow. Dunno if that was it or not, but it's back together all the way and functioning now.

Next step in the evolution of the SB-600: an external power port!
I've got the base apart, but the packaging in there is nearly rediculous it's so tight. I still think there's a way for me to do it, I just need to study it a bit more first.

If anyone's heard of a solution/method for this aspect, I'd love to hear it....:D

Thanks everyone for your help with the zoom issue.
I'm glad that part's over!
(For now............ Buwahahahaha!!!)

Nate

You did a thorough and fine job it seems. But, as you mentioned it may just be the motor has a dead spot too...but I still think it was a factory defect that led to it all~

As for the external power port..I've already done one. I also remotely mounted the light sensor.

yes it's all very tight, but very doable with Radio Shack and some patience.

Below is my ugly duckling~


The piece closest to the forefront is a radio shack 4 AA holder. And mounted on that is a film canister where I can add or subtract exposed 35mm film to get the visible light cut.

Alt view


SO, it works, it's ugly....and I had fun doing it!

NateW

Looks like you've found a way to make it work! Awesome!
But, may I ask a few questions?

If you attached a quad-AA, was the point of the mod only to move the light sensor remotely?
I notice that the packaging for what I assume is the light sensor (what looks like an opaque white LED) makes it look nigh on impossible to attach a wire at that location and not have interference during assembly.

However, since when has nigh on impossible been a block to that rare case of making it work anyway?

And a BTW:
Did you get any shots of where/how you connected everything inside?
I can figure it out with my voltmeter (and prob will, given my patience level for message board speeds... ), but would love to see the shots of how you did it.

Thanks!
Nate

angevin1

NateW wrote:

Looks like you've found a way to make it work! Awesome!
But, may I ask a few questions?

If you attached a quad-AA, was the point of the mod only to move the light sensor remotely?
I notice that the packaging for what I assume is the light sensor (what looks like an opaque white LED) makes it look nigh on impossible to attach a wire at that location and not have interference during assembly.

However, since when has nigh on impossible been a block to that rare case of making it work anyway?

And a BTW:
Did you get any shots of where/how you connected everything inside?
I can figure it out with my voltmeter (and prob will, given my patience level for message board speeds... ), but would love to see the shots of how you did it.

Thanks!
Nate

Gimme a day to catch up, just returned from a trip...I'll see what I can scrounge up for photos.

The point of the mod? Just to see if I could do it!

Actually, if I remember correctly, the batt wires are red and black and are easier to access on the opposite side of the battery door. Yes, It is all a tight fit...at least the first time ...but the second time, I got rid of the on-board battery and now just run mine with an external pack.

Of course, the light sensor is a an easy thing, just de-solder from it's pc board and then run it where ever you like...of course you already know since it is a diode it is directional~

I think replacing the bulb was harder than these other mod's.:D