EQ6 Polarscope Illumination

[MikeP]

I asked a question on this subject in Veracocha's "NEQ6 Power Mod" thread but since I have more questions, I've started this thread.

To recap, my EQ6 Pro polarscope illimination has never worked. It has a LED poking into the polarscope but no means of brightness adjustment - no external rotary control and since it has the older motherboard, no adjustment via the SynScan handset. Since it doesn't seem to glow at all, adjustment is probably a moot point and I need to fix it before attempting the "EQ6 Polarscope Dimmer Mod" that is detailed elsewhere on the forum.

I've disassembled enough to put a multimeter on the two pins on the motherboard that supply the LED and it gives a reading of 1V. Now, I am to electronics what Wolverhampton Wanderers are to football - just a vague idea of what is going on, so I don't know if that is a good or bad voltage.

Since there is a voltage across the two pins and I can't find any loose wires is it safe to assume there is something wrong with the LED?

Before I do something non-reversible, does anyone have any suggestions?

Mike

[steppenwolf]

I am a little worried about that voltage, Mike. I would have thought that you would require a little in excess of two volts for a standard red LED.

If you are out of your comfort zone operating on the circuit board itself, you could make up your own LED module and connect it to the switched 12v rail inside the mount housing and connect a new LED (or keep the original if you ascertain that it is working) via a 1K resistor as a start point.

[m.tweedy]

I think I gave you a link for a led to attach to the polar scope

AWR Technology - Polarscope ILLUMINATOR

will that not save a lot of hassle

[MikeP]

I think I gave you a link for a led to attach to the polar scope

AWR Technology - Polarscope ILLUMINATOR

will that not save a lot of hassle

Yes, you did Michael but I posted in that thread that I already have one and I have found it less than satisfactory, otherwise I'd have one on order - anything for an easy life.

I am a little worried about that voltage, Mike. I would have thought that you would require a little in excess of two volts for a standard red LED.

You are quite right Steve - I Googled some red LEDs and it seemed that 2V is required for (presumably) maximum brightness. I connected a 1.5V battery to the one in the mount and found that the LED definitely glowed. With the mount reassembled and in a dark shed with my eyes dark adapted, the 1V barely illuminates the LED. Certainly nowhere near enough to illuminate the diagram.

Mike

[m.tweedy]

Yes, you did Michael but I posted in that thread that I already have one and I have found it less than satisfactory, otherwise I'd have one on order - anything for an easy life.

Mike

Doh I never thought to check back on the previous thread.

[MikeP]

Thanks anyway Michael, I appreciate you taking the trouble to help.

Mike

[m.tweedy]

could you use something like an old eyepiece with the centre taken out and illuminator at the side and fit it into the hole at the top of the mount

[MikeP]

That's a cunning idea. I've got an illuminated reticle where the illuminator part screws in. I'll have a look at that tomorrow.

Thanks

Mike

[glowjet]

Just in case you want to experiment, Maplin sell two red 12v LED types one bright, code CJ 70M and one standard code CJ 66W both 3mm you can run these straight from your 12v supply, if you want to vary the brightness, then put a 470 Kohm pot in the circuit, they work very well

John.

John

[MikeP]

Thanks John, timely advice. I've decided it is time I educated myself a little bit on electronics so I intend to buy a few bits and pieces or a kit and start experimenting.

Mike