[AU] -Get em while/if you can. 0-30V 2.5A  P/Supply $49 -DickSmith, last stock! - Page 1
Forum section: electronics / general

author: mAJORD
author_rank: Contributor
timestamp: May 27, 2012, 11:22:30 am
content: ....Teardown incomingFor anyone after an entry level supply, or maybe another one (who doesn't) - These old supplies are no longer being stocked after this runs out.They were down to an already decent $99, but recently unknown to me were reduced to$49Model: Q17700-30V Adjustable Voltage0-2.5A adjustable currentRipple: 5mVLine/Load Regulation: +-10MvTo those interested in this. I have to apologise first out. I should have posted this as soon as I saw it yesturday arvo, but wanted to look them up and check them out first.. didn't want to post up and have none for me to pickup todayHowever. Unfortunatly, in the meantime, One DAY later DSE have removed the product page from their website! so you can't look up which stores have them in stock anymore.. argghh (and it's not many)Thankfully I did a quick look around at the time, and I can only remember the following!.. Sorry!BRIS:North Lakes - 1 in stock (I took # 2)Logan Hyperdome : Low stockSYD: One of the western stores came up with Low stock . You'll have to ring up.MELB: - don't believe anyone had stock.All the the other stores, who knows. but whatever they have, that's it.I've only had a quick play, and all seems great. These are a common-ish old unit, and i'm sure theres people here who have one of these. I believe BK and a few others market them aswell.Will follow up with a teardown shortly though.

author: kripton2035
author_rank: Super Contributor
timestamp: May 27, 2012, 12:22:15 pm
content: hum .. cats are always curious he ...? specially new smells ...

author: joelby
author_rank: Frequent Contributor
timestamp: May 27, 2012, 01:15:31 pm
content: I've used one of these before. A perfectly good power supply, and a bargain at $49. Hopefully the local store's still got one in the morning!

author: SeanB
author_rank: Super Contributor
timestamp: May 27, 2012, 01:26:01 pm
content: Wish I could get one, but the postage.............

author: mAJORD
author_rank: Contributor
timestamp: May 27, 2012, 01:27:38 pm
content: Quote from: kripton2035 on May 27, 2012, 12:22:15 pmYes!, Normally out of bounds in the wk/shop as she will play with anything and everything.Some Inside pic's for the curious people (and cats)I didn't want to take the front PCB off, as it's hard to get off without removing the heatsink and everything. Not much to see really, all through hole discrete stuff by the looks.output ripple seems well below specs, even under load. Will put it on the DSO tommorow probably.It has 2 Taps by the way, swtiches over at 15v

author: ciccio
author_rank: Frequent Contributor
timestamp: May 27, 2012, 01:35:01 pm
content: It looks very well built.All required insulations are there, wires are of the correct gauge, heatsink is generous...My impression is that it can give years of service and, in case, be services easily.Best regards

author: Bored@Work
author_rank: Super Contributor
timestamp: May 27, 2012, 01:38:23 pm
content: Probably made by Manson.Likely one of these oneshttp://www.manson.com.hk/en/dcpowersupplies_detail.php?m=3&id=4http://www.manson.com.hk/en/dcpowersupplies_detail.php?m=3&id=5

author: T4P
author_rank: Super Contributor
timestamp: May 27, 2012, 02:33:16 pm
content: Judging from the small knob, it's definitely mansonAnd apparently the heatsink is nice and we all know that costs some money, but i always like a fan ... cheaper lighter

author: joelby
author_rank: Frequent Contributor
timestamp: May 28, 2012, 01:35:55 am
content: I just rang up an Adelaide store and the only one left (not sure if this was nationwide or just on the 'local' radar) is in Mildura. Bit of a long drive!

author: EEVblog
author_rank: Unknown
timestamp: May 28, 2012, 02:26:20 am
content: IIRC these supplies have (or used to have) nasty overshoot at power on.Worth checking.Dave.

author: mAJORD
author_rank: Contributor
timestamp: May 28, 2012, 02:54:39 am
content: Will check that out, thanks Dave.

author: pickle9000
author_rank: Super Contributor
timestamp: May 28, 2012, 06:44:48 am
content: Google this one. Look familiar?BK Precision Model 1670...mike

author: amspire
author_rank: Super Contributor
timestamp: May 28, 2012, 07:13:52 am
content: Quote from: wilfred on May 28, 2012, 07:02:33 amIt doesn't sound good, does it? There is no output switch, so most people will probably carefully connect the circuit up, and then press the ON switch.The problem with unplugging and plugging in the load is that when you start using multiple supplies, meters, etc, it is very easy to plug the wrong lead into the wrong place. It is better if you can wire everything up, double check all the connections, and then leave everything connected until you finish the work.If it does have a startup problem, I would work out how to eliminate the problem or add an output switch.If anyone is checking the supply on a scope, can you check the turn off as well, particularly at no load? If the supply to the regulator circuit dies before the main supply, the output voltage could do anything.Richard.

author: mAJORD
author_rank: Contributor
timestamp: May 28, 2012, 07:23:14 am
content: Quote from: amspire on May 28, 2012, 07:13:52 amSorry I didn't get to capture switchoff, but I could see it just dropped off slowly. Will have another look on the analogue cro here.I did test for overshoot though with and without load..5V No Load:5V , 600mA Load15.2 V (to check switch on with 2nd tap)And a1.4v, with around 100mA load.So no major problems I can see. A bit of noise right at switch on, but minimal overshoot. Perhaps there was an issue at an earlier revision? who knows.Ripple:5V 60mA LOAD3.36mV Pk-Pk16V 2.5A Load3.84mV Pk-PkIt is a Manson BTW, I found it printed on one of the PCBs, Thanks BoredatWork..-edit, oops, 3v ripple haha

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: May 28, 2012, 01:54:54 pm
content: I have an old Manson 9615 that has the power on symptoms.I just thought it was broken and never got around to fixing it and so I always had to make sure that I had critical stuff disconnected during switch on.It was a bit of a dangerous charade, where I always left one banana plug out during switch on and switch off and also while off.It's kind of embarrassing now that I never did get around to fixing it. I was thinking of a delayed turn on of a load relay, but it probably has smaller spikes as the taps change anyway.I only did lose one circuit because of it.I did a quick measurement on my new Fluke 1587 using the min/max. Turning on to 10.5 volts I got a max of 26v first time and 34v second time.I have a dim memory of a 60volt spike when I initially discovered this behaviour.I don't have a storage cro. So no graphs.

author: amspire
author_rank: Super Contributor
timestamp: May 28, 2012, 02:37:15 pm
content: Quote from: HackedFridgeMagnet on May 28, 2012, 01:54:54 pmA storage cro is not needed. A diode and a 10uF 100V capacitor connected to a multimeter tells you everything you need to know. The discharge time constant is 100 seconds so the peak reading on any meter will capture the shortest of overvoltage transients.Richard.

author: Unknown
author_rank: Unknown
timestamp: May 28, 2012, 09:14:01 pm
content: Assuming the output impedance is (almost) zero ohms so the cap is charged instantly.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: May 28, 2012, 10:43:41 pm
content: Not sure why using the cap and diode peak detector would be better than the min/max of the fluke?I don't suppose anyone has the schematic for anoldManson NP-9615. Seems like the newer ones have fixed this problem.

author: EEVblog
author_rank: Unknown
timestamp: May 28, 2012, 10:46:54 pm
content: Quote from: mAJORD on May 28, 2012, 07:23:14 amPossibly, or maybe even clone versions.I was fairly sure one I have measured many years ago looked exactly like this.I remember we fried a proto boards 5V rail because of the overshoot.Dave.

author: amspire
author_rank: Super Contributor
timestamp: May 28, 2012, 11:36:01 pm
content: Quote from: HackedFridgeMagnet on May 28, 2012, 10:43:41 pmThe diode acts as a true peak voltage detector. The fluke has a peak reading memory, so it is limited by the measurement speed. How many samples per second can a Fluke multimeter do?

author: Unknown
author_rank: Unknown
timestamp: May 29, 2012, 12:33:32 am
content: It's not about sampling rate, they don't do continuous acquisition (re-arm time is quite long). In fast min max (peak detect) mode the DMM probably use a similar peak detect scheme, though obviously with much smaller caps and a buffered signal. Minimum duration is usually something like 1 ms or 250 us, even though sampling interval is much longer.

author: amspire
author_rank: Super Contributor
timestamp: May 29, 2012, 12:55:23 am
content: Quote from: alm on May 29, 2012, 12:33:32 amA fluke 87 can see peaks down to 250uS. I assume most cheaper multimeters cannot. Not everyone has a Fluke 87.A diode and a 100uF capacitor will show peaks faster then this. A lower capacitor would obviously be much better if you have a meter with Gohm impedance. It would be easy to breadboard a simple diode-capacitor-opamp circuit that can easily detect output glitches to less then 1uS.The point I was making is you do not need digital scopes or $400 multimeters. You can check your power supply for overshoot with a $10 multimeter and 20c worth of parts, and in terms of detecting overshoot, it can outperform the Fluke 87. It is very easy to start thinking that you can only measure something like overshoot with expensive test gear.But it did remind me of an important point - to check for overshoot with this supply, make sure that the current limit is set to maximum current.If the current limit is at a low setting, it may slow the startup rise time enough for the regulator circuit to stabilize.Richard.

author: mAJORD
author_rank: Contributor
timestamp: May 30, 2012, 07:19:06 am
content: Quote from: amspire on May 29, 2012, 12:55:23 am