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I have recently purchased a Celestron Dew Heater Ring (9.25") and a Pegasus Powerbox Advance (Gen2). However, when I run the heater ring at anything from about 30% to 90% there is a pronounced "ringing" sound coming from the powerbox. The sound reminded me of that which can be heard from a mains lighting dimmer switch, but at a higher pitch.

There is no sound when using traditional dew straps alone. Of course it returns as soon as the dew ring is also attached.
The sound is at its worst when the ring is attached to a dew heater output of the powerbox.
When instead used with an in-line PWM LED dimmer attached to a 12V output of the powerbox, the noise is less, although still noticeable. Interestingly, the noise is also present if the dimmer/heater ring is connected to the same observatory 12V supply before its connection to the powerbox, although is further reduced.

I also have a Gen1 version of the powerbox, which again produces some noise, but it is significantly less that the Gen2 powerbox.

The fact that there is still noise, albeit it less, even when the heater ring is connected to a non-powerbox 12V supply suggests to me that there could be some type of feed back or interference that is affecting the powerbox, and that this is more pronounced in the Gen2 version.

So, my question is has anyone else experienced this issue? Or indeed, is using a Celestron heater ring with a Pegasus Powerbox without this issue? Or is there an incompatibility between the heater ring and the powerbox? Or, is there a fault with the heater ring?

I have Googled for some answers, but to no avail.

I suppose that I could power the heater ring from a completely different 12V supply, but that rather defeats the point in having a powerbox.

Any thoughts?

Adrian

15 hours ago, 1parsec said:

You can increase the clearance of the belt so the belt teeth don't touch by loosening bolts 'A' and moving the motor plate downwards a bit and re-tighten 
Then loosen bolts 'B' and move the motor upwards to tension the belt.

You are looking to increase the distance between the idler roller and the motor 9T pulley.

Many thanks for everyones advice and I have also ordered a replacement belt from Rowan Astronomy

I have a HEQ5 rowan belt conversion which has been in situ for a few years, although not heavily used. However, my guiding has not been particularly good and so I removed the cover to check the belts. I have noticed that the RA belt is buckled and when running actually catches on the teeth of the belt running in the opposite direction, which can clearly been seen in the photograph.

Has anyone else encountered this and what did they do to resolve it?

Thanks
Adrian

I tried using a Logitech Gamepad F710, but found that the wireless connection was frequently lost, usually part way through an observing session. I later read a report that buttons on the F710 can be susceptible to moisture.

I now use a wired gamepad, which although less convenient never looses a connection.

Adrian

The ISS can be picked up with very basic equipment. I managed to hear Tim Peake when he was aboard using a handheld Baofeng UV-5RA.

looking forward to seeing the finished pier/obsy Adrian . it would have looked nicer white mate, to go with the mount.

Sorry about the shameless plug, but Gonzo, he got it from me, I make them to order, either eq5/heq5 or eq6. drop me a pm if you are interested mate.

gaz

You're probably right about the colour, but I can paint the pier black to match which will help

Adrian

Just received my latest toy. Now I just need to build my pier . . . . . and then an obsy!

Adrian