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Mega-mod thread for Zhumell dobs

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#76 scottder

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Posted 05 December 2010 - 04:25 PM

Has anyone replaced the screws that hold the finder in place, one of the plastic ones got 'stripped' so I can't really adjust it now.

Scott

#77 Mary B

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Posted 05 December 2010 - 06:29 PM

Mine arrived with a broken one and Zhummel was quick to drop one in the mail. It is a standard size screw, I tried a 6-32(I think, one of the small screw sizes) and it fit.

#78 scottder

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Posted 05 December 2010 - 07:21 PM

Mary, excellent thanks!

#79 GrafikDihzahyn

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Posted 03 January 2011 - 11:54 PM

I just got my first scope, a Z10 and I am loving it. I used a cheshire/site tube to collimate it, and once I bought a barlow, I used that with my laser. I did have to remove the center spot on my primary and replace with a new one, as the original from the factory was about half a centimeter off. Jupiter looks AMAZING through this thing. Was able to find Uranus while I was out this evening. Couldn't see any of it's moons, but we have a lot of light pollution here.

QUESTION - I've read about the fans for cooling down the primary. The Z10 comes with one, but I've read that it should be blowing air TOWARDS the fan. Mine is blowing air AWAY. Should I remove and reinstall, or is it supposed to be blowing away?

#80 Tim L

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Posted 04 January 2011 - 11:14 AM

QUESTION - I've read about the fans for cooling down the primary. The Z10 comes with one, but I've read that it should be blowing air TOWARDS the fan. Mine is blowing air AWAY. Should I remove and reinstall, or is it supposed to be blowing away?


Hi Grafik,

I think the fan should be blowing toward the mirror, not away. Are you sure yours isn't? Even when pointed in the right direction, the air hitting the mirror will "bounce back" and make a lot of airflow off the back of the scope.

Try holding a piece of string right in front of the fan to see if it's really blowing away from the mirror or not. If it is, reversing it probably isn't too hard.

Clear skies, :rainbow:

#81 GrafikDihzahyn

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Posted 04 January 2011 - 12:48 PM

Yeah, it's definitely blowing the opposite direction. No big deal in removing and switching it around, as I am planning on creating a baffle for it anyways.

#82 Rob E

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Posted 04 January 2011 - 02:45 PM

Does anyone know the polarity (tip) of the battery pack for the fan is for the Z10 ?


Center +
Sleeve -

#83 Rob E

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Posted 04 January 2011 - 02:50 PM

Regarding the fans that come attached to the back of the Z dobs, is it possible to use an alternative battery pack with them? Has anyone done this? Perhaps one of the rechargeable camping batteries with the cigarette lighter style plugs? I don't fancy buying loads of D batteries. To me it's just not economically feasible or ecologically responsible. Besides, I will want to use the camping battery to power other devices as well.


Graffias,

Mine came with a battery pack for AA batteries (8 of them = 12v) to run the fan. I think as long as you're getting the same voltage you could probably use other power sources for the fan. A 9v battery might be a little low on airflow.

I've been thinking of putting some kind of regulator on mine to control how much power the fan gets, so I can turn it down once it's close to ambient, but still have a little air flowing down the tube.


Running the fans at 9v may cut back on airflow but it also minimizes vibrations.

Items like Fans Size adapters and Speed controllers for the computer industry come in very handy.

#84 maakhand

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Posted 04 January 2011 - 08:09 PM

I did have to remove the center spot on my primary and replace with a new one, as the original from the factory was about half a centimeter off.

is it really that much.
:question:

#85 Tim L

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Posted 04 January 2011 - 10:13 PM

Items like Fans Size adapters and Speed controllers for the computer industry come in very handy.


Thanks, Rob :)

Only $4 for a fan speed controller--that price looks right!

#86 GrafikDihzahyn

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Posted 04 January 2011 - 11:09 PM

It was pretty bad. I'm using a regular notebook reinforcement ring to replace the original. The edge of the new ring is on the center of the old one.

Measure twice, stick once.

Not too surprising though, as the fan was actually mounted backwards as well. The sticker was facing out, grill facing in. Other than those simple fixes, this Zhumell ROCKS.

#87 txmnjim

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Posted 05 January 2011 - 08:24 AM

Well, I'm just gonna have to wait until the mirror needs
cleaning b4 I check this issue out ;-) (With someone else's
post about how flimsy the tube is I'm afraid the whole thing
will fall apart if I try and take the mirror cell out!)

#88 maakhand

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Posted 05 January 2011 - 08:01 PM

It was pretty bad. I'm using a regular notebook reinforcement ring to replace the original. The edge of the new ring is on the center of the old one.

Measure twice, stick once.

Not too surprising though, as the fan was actually mounted backwards as well. The sticker was facing out, grill facing in. Other than those simple fixes, this Zhumell ROCKS.

thanks for the update. my fan is backwards too. it sucks the air out. looks like i have to pull the primary too to re-spot it. 'cause after using the telecat xl to collimate i am not impressed. i know i should have used the template before attempting collimation but i just wanted see how accurate it is out of the factory before pulling anything.
did you happen to measure how big was the primary? 10" or 9.75"
does anyone know the size of the secondary in Z10 and whether the FL is 1250mm?
thanks.

#89 txmnjim

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Posted 09 January 2011 - 08:54 AM

go to zhumell.com
fl is 1250 but not sure about the secondary...

#90 Sarkikos

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Posted 09 January 2011 - 10:03 AM

maakhand,

did you happen to measure how big was the primary? 10" or 9.75"
does anyone know the size of the secondary in Z10 and whether the FL is 1250mm?
thanks.


Just take out the primary and the secondary and measure them. I've done that with all my Newts. I have a Z8. Can the Z10 be any more fragile than the Z8?

A white light headband is helpful when working on scope optics so you can have a better view of what you're doing. I take apart all my scopes on the top of my bed. That is the widest, softest surface in the house. Just don't let the covers scratch the mirrors. This isn't rocket science, it's just amateur astronomy! :grin:

Mike

#91 graffias79

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Posted 09 January 2011 - 11:39 AM

Regarding flocking the tube; Suppose I were to buy some felt from Joann Fabrics. What would I use to adhere it to the tube? Would something like 3M Super 77 in a spray can work? I don't want to risk any of it falling off and landing on the mirror!

Thanks

#92 maakhand

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Posted 09 January 2011 - 12:23 PM

thanks mike

#93 Sarkikos

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Posted 09 January 2011 - 01:35 PM

:grin:

#94 Tim L

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Posted 09 January 2011 - 04:41 PM

Regarding flocking the tube; Suppose I were to buy some felt from Joann Fabrics. What would I use to adhere it to the tube? Would something like 3M Super 77 in a spray can work? I don't want to risk any of it falling off and landing on the mirror!

Thanks


Graffias,

That's exactly the way I did it--I got some wonderful dark velvet (not felt) from JoAnne and that 3M spray glue. I rolled the velvet around a long cardboard tube (like a poster tube), temporarily taped the end of the velvet near the scope tube seam, and started spraying and unrolling a little at a time until it was done all the way around. I lastly untaped the initial edge and sprayed the glue in there, too.

Now, here's the problem: It all looked great as one piece, but with the thermal expansion of the tube in different temps, it wasn't long at all before I had the flocking puckering off and drooping in places.

What solved the problem was cutting a slit down the middle of each bubble in the fabric, and lining it with some scotch double-sided tape (the thin kind, not the stuff with foam in the middle). So far, that's working very well.

So my take is that velvet is a very good material to use, but be sure to give it some way to expand and contract with the tube or you'll have to fix it later.

There's a link above in this thread to a good article on how to flock a tube from CN.

Clear skies! :rainbow:

#95 txmnjim

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Posted 12 January 2011 - 04:05 PM

It was pretty bad. I'm using a regular notebook reinforcement ring to replace the original. The edge of the new ring is on the center of the old one.

Measure twice, stick once.

Not too surprising though, as the fan was actually mounted backwards as well. The sticker was facing out, grill facing in. Other than those simple fixes, this Zhumell ROCKS.

thanks for the update. my fan is backwards too. it sucks the air out. looks like i have to pull the primary too to re-spot it. 'cause after using the telecat xl to collimate i am not impressed. i know i should have used the template before attempting collimation but i just wanted see how accurate it is out of the factory before pulling anything.
did you happen to measure how big was the primary? 10" or 9.75"
does anyone know the size of the secondary in Z10 and whether the FL is 1250mm?
thanks.

btw, you might try reversing the polarity on those fan
batteries to see if it blows the opposite direction?
jim

#96 maakhand

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Posted 12 January 2011 - 05:47 PM

thanks jim
i pulled the primary to re-spot it. it measured a hair less than 9.75". center spot was around 3mm off.also found out that the fan was mounted right but its so close to the mirror that air bounces back and gives the illusion that its sucking air.
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#97 skizoid

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Posted 12 January 2011 - 08:14 PM

the fan was mounted right but its so close to the mirror that air bounces back and gives the illusion that its sucking air.


Yup ... I was gonna post something to that effect a few days back, but had trouble getting my shiny new account approved. Third time was the try, with a bit of a hand for the admin.

A bit of a hand for the admin, ok? <clap clap clap>

Oh. BTW - HI!

I'm already kinda regretting ever having seen this thread. Brand new shiny Z8, right out of the box, and I've got it torn to pieces. Two feet of snow outside - figured what better time to get to it? Here's my hitlist so far:

- Loctite OTA seam. Done.

- Add handles to OTA above pivot bearings. Done.

- Add spinner handle on the tube up by the secondary to aid in aligning the scope. Done.

- Replace spotter with Telrad. I'm planning to pop the original spotter off and just drill the Telrad base to accept the same mounting screws. I also replaced the white foam tape with some good 3M body moulding tape after seeing a few comments about the Telrad falling off when it gets hot and the tape fails. In process.

- Flocking. In process. (Ask me about this - I need to get my post count up! <G>

- Resealed and repainted the base after seeing comments about the particle board swelling and going south when exposed to moisture. Gotta figure that's a given, so what da hey, eh. Done.

Added a rubber bumper to the inside back of the rocker box. Already managed to stumble knock the tube into the stand once just screwing around with the mods. The bumper looks suspiciously like one of the new legs - why reinvent the wheel?

- Added a setting circle to the base. That was tricky. Yet another "ask me!". Done.

- Found me a nice digital level for elevation. I've seen a few posts about adding a counterbalance weight at the bottom of the OTA, and figure kill two birds at the same time. The level is quite heavy and should be more than enough to make a killer counterweight. I've got a piece of "C" shaped rail that will accept a sliding carrier. Mount the level to the slider, move as needed, and twiddle a knurled knob to set it in place.

So ... did I miss anything?

#98 MessiToM

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Posted 12 January 2011 - 08:40 PM

Kendrick secondary dew heater
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#99 skizoid

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Posted 13 January 2011 - 12:08 AM

Oh my ... the cost of this inexpensive scope keeps going up ... I'm assUming you also need to upgrade the power pack to run one of these puppies for any length of time. Kendrick's prices on those are ... er ... astronomical! Lucky me, I've got a nice one sitting around that's plug in recharge and even puts out 120v if I need it. I may just slap that on there anyway even just to run the fan. Be nice to have some jams too.

(Drat - now I gotta build some speakers into the rocker box.)

Seems like it'd be a good investment tho - especially up here in cold country. Checked out the website and I see they have wraparound heaters for the two inch stalk mount like I've got on the 8".

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Haven't tried prying the mirror off to see how solid the mount is. Kendrick sez you may have heat transfer problems if it's foam mounted. Anybody sure one way or the other? Might be worth waiting a bit anyway. I see they offer "smart" heaters with dew sensors, but not so far in the barrel mount type. At least not that I could find on their web.

Long as we're talking heaters, any thoughts on a primary heater? Can't imagine why you'd need the fan as well if you went that route - should be plenty of venturi effect to clear the barrel with both heaters running. Then again, sticking with the fan does save $80 - more on a big rig like yours.

#100 MessiToM

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Posted 13 January 2011 - 10:00 AM

Neat wrap around. I don't use the little battery pack anymore. I have a telrad heater eye piece heater and the secondary heater. 8 have a "power tank"I got my kendrick from a vendor at a star part for $40...There was NO foam or badding behind my secondary. It was also very hard to get the secondary out of its holder. Zhumell silicones and 3m tapes it in. I drilled small hole throgh the back of the holder so I could push the mirror out and not crack the secondary holder

Holes in the secondary I drilled
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