EM200 24V Power Supply.

[Tandum]

I want to run my em200 off 24v to speed it up.
I figure this jaycar power supply (http://www.jaycar.com.au/productView.asp?ID=MP3248&keywords=24v+desktop+power+supply&form=KEYWORD) will do the trick.
Any reason not to use this switch mode power supply?

It's a lot cheaper than one of these. (http://www.ccdastro.com/Temmaconverter.html)

[Hans Tucker]

The Jaycar option is virtually identical to the unit I am currently using on my NJP mount...so I cannot see any reason why it won't work. 240Vac to 24Vdc.

The other option you looked at seems ideal if you need to operate remote, away from mains power, using a 12V deep cycle battery. It will step up 12Vdc to 24Vdc to give you max slew speed.

[Tandum]

Hans, can you have a look on the back of that supply and see if it is a switched mode supply. I imagine they would advertise the fact. Or, a switched mode supply would normally be in a totally sealed box were as a linear supply would have some sort of ventilation holes to let the heat out. I don't want to go banging square waves into this mount if it can't handle it :)

[Dennis]

Hi Robin

For my EM200 Temma II, I use a similar unit from Jaycar, a PowerTech 24V 1.8A regulated switched mode power supply, plastic enclosed case. I think I once measured the current draw when tracking and it came in around 0.3A and when slewing, this went up to approx. 0.9A.

I also label all my mains adapters whether centre +ve or –ve to prevent night time fumbling destroying wrong polarity equipment.

For those mains adapters supplied with multiple removable tips (2.1mm, 2.5mm, etc), when I fit the correct tip to the end of the cable, I tape the body of the tip to the end plug, just to avoid any wrong polarity issues.

Cheers

Dennis

EDIT:
At 24V;
Sidereal tracking was approx. 0.3A
Slewing was approx. 0.9A

(I previously quoted my Vixen GPDX mount measurements by mistake)

Cheers

Dennis

[Tandum]

Cheers Dennis, that'll do it. I have no -ve centre sockets here. I run a single 12v cable to the mount and distribute it there via a home brew dew controller/distribution box. One extra 24v cable while at home won't be a problem :)

[Hans Tucker]

Hi Robin,

It is an EOS AC Adapter Model No: ZVC70NS24 (Data sheet attached).

http://australia.rs-online.com/web/search/searchBrowseAction.html?method=getP roduct&R=3777208

[Tandum]

Cheers Hans.

[Dennis]

Robin and Hans

The unit that Hans posted has a fixed 2.5mm DC plug – I think that the Tak control box on the mount has a receptacle for a 2.1mm plug?

Was this an issue Hans, and will this be an issue for Robin?

Cheers

Dennis

[Tandum]

Yes it's 2.1mm, I'll be making a 5meter cable to add to the loom and keep the 240v away from the mount and the dew. I tend to put female RCA plugs on the ends of power supplies and run from that. A 2.5 should plug in but would probably wobble and be unreliable.

[Dennis]

Hi Robin

Just in case you don’t get around to making your loom before you next use the mount, Jaycar has an adapter for a 2.1mm DC Plug to 2.5mm DC Socket, Part Number PA-3704 for $2.95

http://www1.jaycar.com.au/productView.asp?ID=PA3704&CATID=35&form=CAT&SUBCATID=285

Cheers

Dennis

[Tandum]

Caught the flu instead of imaging, but the lurgy is on the way out so I got the new supply and cables done today. It's a lot quicker on 24v, I had some trouble getting a star into the finder cross hairs in fact. But it's all go :)

Here's a handy link from RickS who has also just bought an em200.
http://www.takahashijapan.com/ct-support/supp-pdf/RS232C.pdf
Temma RS232 cable diagram.

[RickS]

The RS232 diagram came from a post by Dennis in an earlier thread. Maybe he can read Japanese? It's difficult to traverse the Takhashi Japan web site if you don't!

Cheers,
Rick.

[RickS]

I found a table specifying power consumption for a number of Tak mounts in the Temma 2/Temma 2 Jr Instruction Manual.

EM-200 Temma 2 is:
DC 12v: 0.42/0.94A (sidereal/high speed)
DC 24v: 0.35/1.07A (sidereal/high speed)

EM-200 Temma 2 Jr is:
DC 12v: 0.28/0.94A (sidereal/high speed)
DC 24v: 0.26/1.94A (sidereal/high speed)

Cheers,
Rick.

[Dennis]

Hi Rick

Just read your PM.

I have 2 auto guider cables for my EM200 Temma II mount as follows:

1. RS232 9 pin (SBIG ST7 camera) to 6 pin Mini-DIN (Tak Mount)
2. RJ12 (SBIG CFW8A filter wheel) to 6 pin Mini-DIN (Tak Mount).

The 1st one is for the ST7 CCD camera without the filter wheel.
The 2nd one is for the ST7 with the CFW8A filter wheel fitted where RJ12 telephone jack plugs into the receptacle on a modified RS232 9 pin connector.

I made the RS232 9 pin D to 6 pin Mini-DIN cable by purchasing a PS2 mouse cable from Jaycar, snipping off one end and soldering on an RS232 D connector.

I think that I got Queensland Cables & Connectors (http://www.qconnect.com.au/)to make the RJ12 to 6 pin Mini-DIN because I wasn’t too confident about soldering the thin wires in a telephone type cable.

I’ve attached a schematic of the RS232 to 6 pin Mini-DIN.

Cheers

Dennis

PS - I can't read Japanese - I got lucky through blindly clicking on the links!

[RickS]

Thanks very much for that, Dennis! I should be able to make everything I need now.

Cheers,
Rick.