Author Topic: Any opinions on this power supply? Tenma 72-10480 (0-30v, 0-3A, 1ma increment)  (Read 2523 times)

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
I made a new cathode using my 0.4mm copper wire and made it a bit longer. I just quickly turned on the unit again with my finished ~80ppm to see how it would read. I think it got to something like 15v and my multimeter was reading 20.3 or 20.8 ma (I forgot) but it was stable, at least as far as my 0.1 ma resolution since I cannot measure any better for 20ma or higher. So I think this is going to be PERFECT! I just have to get more water eventually.

Online cfnisbet

  • Administrator
  • Participant
  • *****
  • Posts: 2558
  • Likes: 184
Seems excellent; well done!

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
Thanks. I am really really happy. I still look forward to the tutorials though on builds for people.

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
Would 100ppm be long-term stable with malto? I am impatient for my water to arrive and I am wondering if I should take my initial 80ppm batch which was "decent" and add the required malto amount to accommodate for another 20ppm and give it another 20ppm whirl to bring the 80ppm to 100ppm, which would let me see how the current and voltage holds up?

Edit: I am doing a test any way even if I have to throw it out. It is dancing around. I put it on 15ma so I can see 0.00 resolution on my multimeter and it still is dancing around. The cathode is exactly the same as it was when I thought it was stable. Either way, I can leave it and it will be good enough, still stable when I make my 80ppm even if it's 1 or 2 ppm off target because of a bit of fluctuating current.

No idea why but it goes into fits and starts of clicking and scraping sounds like a Geiger counter almost. No idea what that is all about but it is very unsettling...
« Last Edit: March 13, 2020, 07:02:38 PM by Turbidaceous »

Online cfnisbet

  • Administrator
  • Participant
  • *****
  • Posts: 2558
  • Likes: 184
Yes, it should be fine at 100ppm.

I have bought one of these units and my only reservation as others have pointed out, is that you must hook up a proper ammeter to the output, as the unit PSU meters are not very accurate, although the Constant Current circuit is perfectly adequate.

My first two batches of Cinnamon-capped colloidal silver turned out perfectly. Thanks for pointing me in the direction of this unit. I use Silvertrons for unattended production or for extremely accurate production, but for my own casual use where the ppm can be within 1-2 ppm of the desired endpoint, this is fine. If one is making 40 ppm as I normally do, the difference between 38-42 ppm is not a particular concern, as I normally let it run a bit longer anyway.

An excellent unit, and I commend it to anyone who wishes to buy a laboratory PSU.
« Last Edit: March 14, 2020, 02:24:36 PM by cfnisbet »

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
Wow high praise, glad I went with it. So the fluctuations in current are experienced by you also? I do measure separately using a multimeter. I did not realise this was pinned, so I did not notice you replied :D

Also, did you get any clicking and scraping sounds?

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
Here's a video of mine clicking: https://www.youtube.com/watch?v=MS67QUjgCvU It only does it once it reaches a certain voltage. Before with my other cathode it was once it hit about 21v I think. Now it's in the late 13v it starts happening.
« Last Edit: March 13, 2020, 10:20:12 PM by Turbidaceous »

Online cfnisbet

  • Administrator
  • Participant
  • *****
  • Posts: 2558
  • Likes: 184
Wow high praise, glad I went with it. So the fluctuations in current are experienced by you also? I do measure separately using a multimeter. I did not realise this was pinned, so I did not notice you replied :D

Also, did you get any clicking and scraping sounds?
Slight fluctuations, but I am of the opinion that this is the CC circuit compensating for slight variations in the conductivity of the bulk fluid (but I may be wrong). When the end of the run approaches and the conductivity is fairly even, the CC circuit on mine holds rock-solid.

The clicking sounds are the relays in the circuitry kicking in. Nothing to worry about, and is a sign of efficiency. Definitely does need a separate ammeter, though.

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
That makes me feel better. I was worried about the clicking. I have a question. My 100ppm batch from start to finish came out mildly turbid, like I can see through but nowhere near as fine detail. But I just now took my last ever cold production of 20ppm which was solid gold perfection!! And I added the right amount of malto and calculated for 80ppm (since it is already 20ppm) to make it 100ppm and it is remarkably more clear in terms of ability to see details through it. So since the last stage from 20 starting up to 100ppm finish using my new power supply and anode along with heat, why would my 0-100pm from start to finish not be the same clarity? I hope I am conveying this question adequately.

Online cfnisbet

  • Administrator
  • Participant
  • *****
  • Posts: 2558
  • Likes: 184
There's a possibility that you might get even better results by dialling down the amperage a little.

Sometimes, I see some turbidity if the reaction proceeds too fast. If it dilutes properly, then there's no cause for concern.

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
To  my eye they are indistinguishable once diluted. Except my worst batch which I believe was boosted to 100ppm from an older 20ppm batch I made with my 10g bullion with the folded silver harness for it and that one is a slight slight bit more on the orange side but not by a vast amount, just a little bit deeper than the perfect dilutions to 20ppm. Would you say that old batch of 700ml in a clean whisky bottle is worth keeping and using? Or do you think that slight tinge towards orange means it's no good? It is possible it is a bit stronger I suppose since I was using my manual potentiometer tweaking approach at that stage. I could throw it out but if you think it would be still good I may keep it.

Online cfnisbet

  • Administrator
  • Participant
  • *****
  • Posts: 2558
  • Likes: 184
If its Johnson's Baby Shampoo yellow and clear when diluted, then keep it.

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
I chucked it out. It may have been ok but better to go with what I know. I may have buggered up my new batch because I forgot to fire-clean the anode and it has started off with a yellow tinge way earlier than expected. So I have a feeling this one is going to be more potent than 100ppm if I go the full time. I may have to try to eyeball it and stop it when the colour looks right :(

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
The old link no longer works. Here's the new link to the device: https://cpc.farnell.com/tenma/72-10480/power-supply-1ch-30v-3a-adjustable/dp/IN06822?st=tenma%20power%20supply

Also you can paste this into the search bar on CPC and find it that way: 72-10480
« Last Edit: March 29, 2020, 10:55:42 AM by Turbidaceous »

Offline Turbidaceous

  • Participant
  • **
  • Posts: 472
  • Likes: 6
  • Living in the UK
The clicking I mentioned before just made it kick off the output... Not only off but it went back to M1 profile which I use to power my old CPU fan on my desk about 350ma and 15v and I started it without realising for a second or two before I stopped it and switched back to M3 for 15ma. I hope it has not messed up my batch. I am purposefully trying to do 15ma to see if there's any difference and now it just got blasted with 340 ish miliamps for a second or two. :(

Edit. Luckily I did a really quick test and it only went to about 17ma at that voltage so luckily it should not have made any appreciable impact. I hope..