Anyone near Kenilworth, UK got an X-Ray  - Page 1
Forum section: electronics / projects

author: perdrix
author_rank: Frequent Contributor
timestamp: January 03, 2024, 09:45:32 am
content: I've got a couple of multi rail power bricks that are supposed to output -15V, 0V, 15V and 5V.The problem is that the -15V output from both of them is low (about -14.4V or so).I'd like to reverse engineer them and an X-ray would help a lot in terms of knowing how the tracks run...I there anyone near Kenilworth able to help...ThanksDavid

author: Buriedcode
author_rank: Super Contributor
timestamp: January 04, 2024, 01:36:17 am
content: Got a part number of those? Sometimes manufacturers will actually specify the topology used (Like Murata)

author: perdrix
author_rank: Frequent Contributor
timestamp: January 04, 2024, 10:25:59 am
content: The supply is a Sinpro SPU45E-303. I contacted Sinpro and they declined to provide any details.David

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 04, 2024, 02:47:43 pm
content: I first thought these were potted, but after seeing a picture, I assume you're just having trouble with the outer housing. Those are often ultrasonically welded, and the weld seam is often much weaker then the rest of the plastic. Often you can open these by stressing the seem. For example by (half) gently tapping with a hammer and chisel (or abuse a screwdriver) directly on the seem.Often they crack open along the seem, and you can then glue the halves together again after repair.They are already broken, so there is not much to loose.

author: Wolfram
author_rank: Frequent Contributor
timestamp: January 04, 2024, 02:56:32 pm
content: Do you need the negative output to be to within less than 4 % of the nominal rating? The datasheet regulation spec for this rail is 10 %, so it's probably more sensible to either find a way to relax your requirements, or to find a supply with a tighter specification.The supply is likely a multi-winding flyback, giving limited options for adjusting each output individually. There's also the issue of line regulation and cross-regulation, even if you get it closer to nominal in the no-load case, the other rails will likely be affected, and voltage will still change significantly when you load the -15 V rail, and when you load the main 5 V rail. How does the 15 V output behave when you load it? How about when you load the main 5 V rail? Are you applying the minimum 0.5 A load required on the 5 V rail for these measurements?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 04, 2024, 03:05:49 pm
content: Try a local vet.

author: perdrix
author_rank: Frequent Contributor
timestamp: January 04, 2024, 04:30:07 pm
content: The case is trivial to open - just four screws.D.

author: perdrix
author_rank: Frequent Contributor
timestamp: January 04, 2024, 04:32:02 pm
content: Quote from: mikeselectricstuff on January 04, 2024, 03:05:49 pmLast time anyone I know had dealings with a vet their bank account almost had an apoplectic fit! That said - it's worth a try. ThanksDavid

author: perdrix
author_rank: Frequent Contributor
timestamp: January 04, 2024, 04:43:20 pm
content: I bought them second hand and they appeared to do what I wanted....I'd missed the minimum load on the 5V rail and admit I hadn't checked the datasheet for regulation. So I guess its performing to spec. The 5V rail seems spot on with no load so I'm not clear why they specify a minimum load.Hmm chances to find a better one seem limited unfortunately.Sad that most of my power bricks deliver their rated output voltage within 1-2% between no load and full load without batting eyelid but this can only manage 10% on a secondary output.D.

author: Andy Watson
author_rank: Super Contributor
timestamp: January 04, 2024, 05:07:02 pm
content: Quote from: perdrix on January 04, 2024, 04:43:20 pmMy guess would be that only the 5V rail is regulated. They rely on the turns ratio fo the transformer to obtain the other rails. Try loading the 5V - it might improve the other rails.

author: jpanhalt
author_rank: Super Contributor
timestamp: January 04, 2024, 10:09:04 pm
content: On places to try:If you know a radiologist, that is the best bet. I had a suspicious fitting for an airplane X-ray'd by one I knew. Free.A school for radiology techs.A pathologist who does autopsies (most do). Your primary care physician might help out there.An aircraft repair station or anyplace that does X-ray for faults. They will almost certainly charge.

author: chilternview
author_rank: Frequent Contributor
timestamp: January 04, 2024, 10:30:23 pm
content: Your friendly dentist might help out (for a suitable fee), they are always wanting to xray my teeth.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 05, 2024, 12:31:38 am
content: Quote from: chilternview on January 04, 2024, 10:30:23 pmdental x-rays may have too small a field of view

author: p.larner
author_rank: Frequent Contributor
timestamp: January 18, 2024, 02:22:22 pm
content: what about warwick uni as its just up the road,try asking there.