My new power supply. IMPO type: 11.11. - Page 1
Forum section: electronics / general

author: Halvmand
author_rank: Regular Contributor
timestamp: November 04, 2015, 03:59:19 pm
content: I'm always looking for a good deal on the things I need, and yesterday I found this gem on the net. So I picked it up today.It is an IMPO type 11.11 0-30 V 0-3 A linear power supply. The supply is made in Odense Denmark in april 1989, just a year before I was born.So it is over 25 years, but looks almost new.Nothing much on the inside, just a classic linear supply with an mc1723cp linear regulator chip, the big transformer with relays and all the passives. 2 2n3055 is bolted to the chassis under the unit.I's not an HP or power designs, which is what I really wanted, but I think I'll be happy. Extremely happy considering the price. 150 DKK, thats about 21 $.I of course included some pictures, since most of you probably haven't seen a danish power supply before. Enjoy!

author: fivefish
author_rank: Frequent Contributor
timestamp: November 04, 2015, 04:44:33 pm
content: Nice score! 723 chips are still in use until today.Maybe it's time to change the electrolytic capacitors. They could be dried out by now/out of spec.

author: zirlou21
author_rank: Newbie
timestamp: November 04, 2015, 04:51:38 pm
content: ...sir can you provide the schematic diagram,I'm interested in building one too.thnx

author: SeanB
author_rank: Super Contributor
timestamp: November 04, 2015, 05:41:18 pm
content: They probably are fine, they will not be run very hard in this application, and so long as the ripple voltage on the capacitor is too high they will last a long time.

author: Halvmand
author_rank: Regular Contributor
timestamp: November 04, 2015, 06:29:37 pm
content: Quote from: fivefish on November 04, 2015, 04:44:33 pmThanks.That big filter cap is danish too. It'll never dry outI'll check the output with a load on it to see if everything is in order when I get home on friday.I'm at my parents at the moment, but found some car bulbs to test it with. A H7 bulb draws the maximum of 3A at 6V and the pass transistors can still be touched without hurting. I guess it's just fine.Quote from: zirlou21 on November 04, 2015, 04:51:38 pmI could not find the schematic. You could try email somebody at IMPO. They are still alive:http://www.impo.dk/Quote from: SeanB on November 04, 2015, 05:41:18 pmI think they are fine too. I don't think it have seen that much use in it's 26 years. The pcb is clean, and no signs of things that have overheated.Not like some other pieces of gear where the pcb has gone black around many of the resistors.I was actually quite surprised when I opened it because it's so clean.

author: bitseeker
author_rank: Super Contributor
timestamp: November 04, 2015, 10:09:07 pm
content: Thanks for the photos, Halvmand. I had not seen a Danish supply before. It's very clean for an 80's device. Great score!

author: Halvmand
author_rank: Regular Contributor
timestamp: November 06, 2015, 12:09:58 am
content: Glad you appreciate it Bitseeker.I had the time to test it a little bit today, and found a potential problem and a minor annoyance.The problem: I loaded it with an 8 ohm resistor and found some 50 hz 5V pp ripple when it goes in to current limmiting. otherwise the output is clean up to 3 amps. I'll investigate that further. Maybe five fish was right about the capacitors.The annoyance: On the pcb there is a little incandescent bulb that light brighter proportional to the output voltage. This illuminates the display pretty good from 15 V and up. Otherwise it's useless and annoying. I'll have to get the schematic to see the function it has, and maybe mod it to a constant light or non at all.

author: hcapela
author_rank: Contributor
timestamp: June 19, 2021, 11:55:42 am
content: Good morning,This device came to my hand with bad contact at the exit, which I have solved in some time.Now that I'm using it, and I'll get more information about , I came to this site the only one that talks about it.Has the author already found the schema? for my future maintenance or repairs.Well I looked on the Net but nothing.Best Regards, H Capela