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Old 18-10-2016, 07:44 AM
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wasyoungonce (Brendan)
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Hi Glen

I feel like a drunk idiot wandering in the dark. We'll get there...someday.

I'm only using silicon thermal compound atm. Will do to something better when we build the damn thing. This thread sure does provide plenty of laughs!

New controller WH17016C and TEC2-19003 ordered.

Now...about my power supply....

Last edited by wasyoungonce; 18-10-2016 at 02:30 PM.
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  #322  
Old 18-10-2016, 04:42 PM
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wasyoungonce (Brendan)
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Been on the hunt for a variable power supply today! Lots to be had quite cheaply but some do appear to be a little inferior. That said they are cheap. Lets say a 32V 10A unit from ~$100~$150 fleabay aust.

But I was looking at EEvblog and basically they said most suffer from switch on overshoot although new units, particularity the switchmode units are better. Also Instek and Mastech units are better and most other brands are copied from these.

All this said...I was eyeing off a Uni-T UTP1035, 32V, 5A unit.

Has anyone have an opinion on all these variable PSUs? Particularly from experience. I need to buy one soon so I cannot wait for one to pop up on fleabay.

Anyone?
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  #323  
Old 18-10-2016, 09:25 PM
gehelem (Gilles)
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Hi Brendan,
here is my lab PSU :
https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_ 20161018032157&SearchText=+KA3005D

i'm quite happy with it, it works well for a few month now.
Gilles.
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  #324  
Old 18-10-2016, 09:26 PM
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Brendan, I am not sure about the Uni-T unit but at the lab we used GW (Instek) GPS series power supplies. Mainly GPS-3030 and GPS-1850. Nothing but good to say about them. We probably had > 30 units running all the time and only 2 broke during my 10 years of work there... and the failures were caused by electrolytic capacitors leaking and were simple to fix. The noise levels on the DC output was extremely low and they could also be computer controlled.
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  #325  
Old 18-10-2016, 09:30 PM
gehelem (Gilles)
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Forgot to say i'm also trying two of these little babies :
https://fr.aliexpress.com/item/DP30V...9-cbabbbfa7bcb
No advice for the moment. They just work...

Gilles.
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  #326  
Old 18-10-2016, 10:16 PM
flolic (Filip)
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I am using Rigol DP832 tripple output PSU, but that one is on the expensive side...
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  #327  
Old 19-10-2016, 02:17 AM
pat30 (Patrice)
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Quote:
Originally Posted by gehelem View Post
Forgot to say i'm also trying two of these little babies :
https://fr.aliexpress.com/item/DP30V...9-cbabbbfa7bcb
No advice for the moment. They just work...

Gilles.

Thanks you Gilles, I did not know it. I've seen better, 15 Amp, I think order soon
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  #328  
Old 19-10-2016, 09:30 AM
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wasyoungonce (Brendan)
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Thanks Gents all good info for me to look up.

Yes Rigol, Instek are well known good ones. I read many of the knock off designs copy from Instek. Emona here in Australia sell some nice units (Rigol, Instek)...decent pricing...errr not quite but still nice. My guess is 5A unit is plenty but if I buy cheap..maybe a 10A unit would better suit.

Those Korad look a damn nice and nice price. Also those smaller switchmode units, but I'd need a Transformer rectifier unit. I kinda like the idea of a Switchmode units as they are way more efficient which means less heat. They are cheap as well!

I'm kinda a cheap a** and like the idea of building my own as have always done, but this project has poked holes in my equipment availability.

Once again many thanks lots to look at...but I'll be getting something ASAP.

Brendan

edit:
There is a nice BWD246A for sale on IIS and it has price dropped...but I feel even though they are very good, even if I offered $300, that's almost the price of new PSUs.

Last edited by wasyoungonce; 19-10-2016 at 10:18 AM.
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  #329  
Old 19-10-2016, 07:13 PM
flolic (Filip)
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Regarding TECs (even that I already solved that problem on my camera), just for a experiment I will order two units, TEC1-07102 and TEC1-03506.
I will stack them together and connect them in series, I think that should provide quite big temperature differerence with low supply power.

From my limited experience, lower powered TECs (for the physical size) tend to perform better for this application. Also, thicker units with lower number of thermocouples perform better.
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  #330  
Old 19-10-2016, 10:32 PM
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It looks like delaying the PCB manufacture paid off. A recent comment from the Ukrainian forums:
Quote:
I would like to add a clarification regarding cooling.
As it turned out http://www.astroclub.kiev.ua/forum/S...efault/sad.gif , Cooling control transistor VT1 (IRFML8244TRPBF) still occasionally burn out because of its tiny body. Therefore it is recommended to put anything or notebook with upravleneim logic level navrode this transistor: IRLI3705NPBF. Or the other MOSFET, controlled from 3 volts, which is available or in store.
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  #331  
Old 20-10-2016, 03:38 AM
perdrix (David)
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Better USB connector

Bren and others

I was at Electronic Design Show in Coventry UK today and came across some nice IP68 circular size 00 USB connectors by a company called ODU who are based in Germany. The connectors are similar to Lemo size 0 but cheaper .

The come in "break away" or locking types. for the free plugs, and the sockets can be PCB mount or panel mount with a flex PCB cable to a connector on the PCB. Pricing isn't bad either (awaiting info). The also do size 00 power connectors rated to 3A if you want to bring in 12V as as well as the USB five volts.

They do prebuilt cables from their connector to a standard USB (2.0 or 3.0 depennding) in 0.2mtr or 2mtr lenghts.

HTH
Dave
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  #332  
Old 21-10-2016, 04:07 AM
flolic (Filip)
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I don't see a point finding special sealed USB or power connector. On a few of my cameras I just covered outside surfaces and pins of those connectors with a RTV silicone and that works extremely well.

Of course, that should be done after you connect wires to them and mount them to the camera
enclosure.
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  #333  
Old 25-10-2016, 09:16 AM
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wasyoungonce (Brendan)
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Anyone has issues with VT1 peltier FET? Grim said he destroyed a few but of course he didn't say what sort of current he was passing. Current VT1 is marginal in specs in any-case.

Looking at using IRF7832 in S08 package as the specs at Vgs ~3~3.3V (gate signal from ATMEga328) is at this level. Doing drawings up for this change now, have to put it on base of PCB but that's not an issue with it's higher current paths.

Brendan
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  #334  
Old 26-10-2016, 10:08 PM
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Did you see faddy's post on the Ukrainian forums, he/she got almost zero humidity inside a sealed enclosure. The enclosure has desiccant and was also filled with kryptonm (dry gas). Dew point is <50 degrees C below ambient resulting in absolutely no condensation anywhere.

Faddy is using a separate humidity sensor inside the enclosure with a microcontroller outside. This could be a good indicator for when camera needs purging if we have spare pins.
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  #335  
Old 27-10-2016, 09:02 AM
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Hi Luka yes I saw this. Pretty good work. He did have trouble sealing the camera with his wires thru the case.
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  #336  
Old 27-10-2016, 11:59 AM
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Yes, is is difficult to bond to (diecast) aluminium. Silicone does not work too well. Epoxy would have done the job but it is more-or-less a permanent solution. Cyanoacrylate (superglue) also seems to bond well.
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  #337  
Old 28-10-2016, 09:55 AM
flolic (Filip)
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Guys, I use this stuff (ebay item no. 121155304226) for all kind of sealing, potting, fixing components... It is some kind of thermally conductive RTV silicone. I don't know about it's thermal properties, but all other are great

It's cheap, it's thick but flow nicely, it stick to all kind of materials but can easily be removed if needed.

Two pictures showing how I sealed wires to a CCD chamber:
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  #338  
Old 28-10-2016, 07:22 PM
Gary47 (Gary)
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Quote:
Originally Posted by luka View Post
Yes, is is difficult to bond to (diecast) aluminium. Silicone does not work too well. Epoxy would have done the job but it is more-or-less a permanent solution. Cyanoacrylate (superglue) also seems to bond well.
Hi Luca,
Cyano will not bond to some plastics. Also how do you get the cyano to set in an unsealed area? I have used accelerant to set it in gap fill situations but the accelerant that I had makes it brittle and porous.
Gary
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  #339  
Old 28-10-2016, 07:24 PM
Gary47 (Gary)
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Quote:
Originally Posted by flolic View Post
Guys, I use this stuff (ebay item no. 121155304226) for all kind of sealing, potting, fixing components... It is some kind of thermally conductive RTV silicone. I don't know about it's thermal properties, but all other are great

It's cheap, it's thick but flow nicely, it stick to all kind of materials but can easily be removed if needed.

Two pictures showing how I sealed wires to a CCD chamber:
Is this stuff neutral cure?
Gary
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  #340  
Old 28-10-2016, 11:30 PM
flolic (Filip)
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As far as I can see, yes. It doesn't have typical acetic acid odor of "bathroom" silicone.
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