How should I open a Busch & Muller Lumotec round front light?

[Paulmouk]

I've got one of these lights on my bike.

'Busch & Muller Lumotec round Switchable Front Light ONLY for Schmidt
dynohub'

It kept flickering and the supplier (SJSC) exchanged it without a quibble.
The new one arrived and when I tried lifting the little locking catch that
releases the front lens cap I snapped it off. It seemed much too weak as I
was only using a thumbnail to lift it.
I sent that one back and light number three arrived today.
There are no instructions with it and I can see no way to release the lens
except by lifting that catch (it only needs lifting a couple of mm to
release a little hook and then the front of the light turns).

I tried easing it up very gently with my nail and again it has snapped off.
Am I doing something wrong?
Are these lights rubbish?

(I've had a B & M Oval plus for several years and had no problem with it but
the catch is different).

Thanks very much,
Paul.

Remove junk to reply

[m-gineering]

Paulmouk wrote:
>
> I've got one of these lights on my bike.
>
> 'Busch & Muller Lumotec round Switchable Front Light ONLY for Schmidt
> dynohub'
>

> There are no instructions with it and I can see no way to release the lens
> except by lifting that catch (it only needs lifting a couple of mm to
> release a little hook and then the front of the light turns).
>
> I tried easing it up very gently with my nail and again it has snapped off.

As you found out, do not try to lift the tab. Instead grab the reflector
in your hand and push with your thumb against the tab. Try not to lift
the tab, merely pushing is enough and rotate the reflector. It should
now come of. R&M recommend just to turn the reflector firmly.
The flickering of the previous light could have been caused by adjusting
the light when it has been firmly screwed down. This could cause the
contact lip to turn in the housing and loose contact with the bulb. If
this happens bend the lip forward again, and ease the mounting bolt a
bit before readjusting
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

[m-gineering]

Paulmouk wrote:
>
> I've got one of these lights on my bike.
>
> 'Busch & Muller Lumotec round Switchable Front Light ONLY for Schmidt
> dynohub'
>

> There are no instructions with it and I can see no way to release the lens
> except by lifting that catch (it only needs lifting a couple of mm to
> release a little hook and then the front of the light turns).
>
> I tried easing it up very gently with my nail and again it has snapped off.

As you found out, do not try to lift the tab. Instead grab the reflector
in your hand and push with your thumb against the tab. Try not to lift
the tab, merely pushing is enough and rotate the reflector. It should
now come of. R&M recommend just to turn the reflector firmly.
The flickering of the previous light could have been caused by adjusting
the light when it has been firmly screwed down. This could cause the
contact lip to turn in the housing and loose contact with the bulb. If
this happens bend the lip forward again, and ease the mounting bolt a
bit before readjusting
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

[Sheldon Brown]

Paulmouk wrote:

> 'Busch & Muller Lumotec round Switchable Front Light ONLY for Schmidt
> dynohub'
>
> It kept flickering and the supplier (SJSC) exchanged it without a quibble.
> The new one arrived and when I tried lifting the little locking catch that
> releases the front lens cap I snapped it off. It seemed much too weak as I
> was only using a thumbnail to lift it.
> I sent that one back and light number three arrived today.
> There are no instructions with it and I can see no way to release the lens
> except by lifting that catch (it only needs lifting a couple of mm to
> release a little hook and then the front of the light turns).
>
> I tried easing it up very gently with my nail and again it has snapped off.
> Am I doing something wrong?

Yes, you don't need to lift the catch, just rotate the reflector housing
counterclockwise ("auf") The "catch" is just a detent, no need to pry
it. It is a moderately stiff detent, you need to turn the reflector
housing fairly forcefully.

> Are these lights rubbish?

Nope.

Sheldon "Fiat Lux" Brown
+------------------------------------------------------------+
| A touchstone to determine the actual worth of an |
| "intellectual"--find out how he feels about astrology. |
| --Robert A. Heinlein |
+------------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

[Sheldon Brown]

Paulmouk wrote:

> 'Busch & Muller Lumotec round Switchable Front Light ONLY for Schmidt
> dynohub'
>
> It kept flickering and the supplier (SJSC) exchanged it without a quibble.
> The new one arrived and when I tried lifting the little locking catch that
> releases the front lens cap I snapped it off. It seemed much too weak as I
> was only using a thumbnail to lift it.
> I sent that one back and light number three arrived today.
> There are no instructions with it and I can see no way to release the lens
> except by lifting that catch (it only needs lifting a couple of mm to
> release a little hook and then the front of the light turns).
>
> I tried easing it up very gently with my nail and again it has snapped off.
> Am I doing something wrong?

Yes, you don't need to lift the catch, just rotate the reflector housing
counterclockwise ("auf") The "catch" is just a detent, no need to pry
it. It is a moderately stiff detent, you need to turn the reflector
housing fairly forcefully.

> Are these lights rubbish?

Nope.

Sheldon "Fiat Lux" Brown
+------------------------------------------------------------+
| A touchstone to determine the actual worth of an |
| "intellectual"--find out how he feels about astrology. |
| --Robert A. Heinlein |
+------------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

[Zog The Undeniable]

Paulmouk wrote:

> I've got one of these lights on my bike.
>
> 'Busch & Muller Lumotec round Switchable Front Light ONLY for Schmidt
> dynohub'
>
> It kept flickering and the supplier (SJSC) exchanged it without a quibble.
> The new one arrived and when I tried lifting the little locking catch that
> releases the front lens cap I snapped it off. It seemed much too weak as I
> was only using a thumbnail to lift it.
> I sent that one back and light number three arrived today.
> There are no instructions with it and I can see no way to release the lens
> except by lifting that catch (it only needs lifting a couple of mm to
> release a little hook and then the front of the light turns).
>
> I tried easing it up very gently with my nail and again it has snapped off.
> Am I doing something wrong?
> Are these lights rubbish?

They are generally held to be less reliable than the oval version by
people who have used both.

[Zog The Undeniable]

Paulmouk wrote:

> I've got one of these lights on my bike.
>
> 'Busch & Muller Lumotec round Switchable Front Light ONLY for Schmidt
> dynohub'
>
> It kept flickering and the supplier (SJSC) exchanged it without a quibble.
> The new one arrived and when I tried lifting the little locking catch that
> releases the front lens cap I snapped it off. It seemed much too weak as I
> was only using a thumbnail to lift it.
> I sent that one back and light number three arrived today.
> There are no instructions with it and I can see no way to release the lens
> except by lifting that catch (it only needs lifting a couple of mm to
> release a little hook and then the front of the light turns).
>
> I tried easing it up very gently with my nail and again it has snapped off.
> Am I doing something wrong?
> Are these lights rubbish?

They are generally held to be less reliable than the oval version by
people who have used both.