Author Topic: Inductor identification without schematic  (Read 264 times)

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Offline BenKenobi

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Inductor identification without schematic
« on: February 05, 2019, 10:42:45 pm »
I have a Bowens 500DX flash head sitting on the bench, the control board has released the magic smoke.

The company no longer exists and schematics are impossible to find. I need to replace a pair of inductors, I have next to no information on what size they are - or do I ?? - I can find no inductors of the value on the top of these.

Anyone care to take a gander at the images and offer some clues - I'm a rank amateur in this game so I don't encounter these things that often. It is in a remote switchable circuit providing 5VDC to a control board in the flash unit, least I think it should be 5V based on the presence of PIC's and LM358N, MC7805C elsewhere- why inductors in + and - ??

What insanity would cook inductors such that the copper ends up on the PCB - I see no evidence that there's been any kind of short in the DC side except the inductors - did the switch shorting kill the inductors or the other way around? but it's all cooked so nothing to confirm who failed what and I lack the experience many of you guys have, how do you know whether the numbers on the inductors are nano or micro henry's ? - there are no vendor markings at all. The PWM switch is toast - actually exploded - it is also obsolete.  http://www.theplasticshed.co.uk/images/images500DX/TOP200YAI.pdf

If the images are too large just let me know and I'll shrink them




« Last Edit: February 05, 2019, 11:46:04 pm by BenKenobi »
 

Offline DaJMasta

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Re: Inductor identification without schematic
« Reply #1 on: February 06, 2019, 01:23:32 am »
If you can ID the manufacturer, the markings may be helpful, but much like a lot of other passives, the markings are pretty minimal and can't really tell you the full story at a glance.  Do you have at least one functioning inductor that you can measure?  Can you match wire diameter and number of turns and reuse the core?

I don't actually see the images...
 

Offline BenKenobi

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Re: Inductor identification without schematic
« Reply #2 on: February 06, 2019, 02:23:47 am »
Wish I did have a good one, both inductors are toast, no vendor markings at all, thinking of getting some 10 millihenry - the large cap is 400V 10 microfarad, can't read the small one without pulling components.

There's an MC7508C nearby (Fairchild) that looks like it has been replaced - although the solder below the PCB says yes, the solder on top says no but without the schematic I've no idea if this is even the appropriate component.

If anyone here has a picture of a Bowens Esprit DX500 control board that would help confirm - or even a schematic / parts list (beer tokens available).
 


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