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Power supply/charger based on an LM338

Tex

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Joined
Dec 16, 2019
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Ok, so I have dug out and old power supply based on an LM338 I made (under instruction) years ago, the original transformer died, so I just cut all the wires and kept the electronics back then.
I am now trying to resurrect it with a new transformer, partly with the intention to use it to charge various Lipo packs I have built with various voltages.
My issue is I have assembled it as best I could recall with reference to a few schematics (not my long suit). The first issue is it has a few extra components I was advised to use when I originally built it just to add to the confusion, the second issue is it is not working correctly, starts at about 2 volts and drops instead of raising on a 16 volt supply.
I did a very rough schematic (see attachment) to try to verify the layout, but I am now just giving myself a headache.
I'm pretty sure the LM338 is ok, so my question is can anyone run their eye over the attachments and tell me if they see an obvious mistake please?
 

Attachments

  • Adjustable-Voltage-Regulator-using LM338 (1).jpg
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  • Adjustable-Voltage-Regulator-using LM338 (1).png
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  • Adjustable-Voltage-Regulator-using LM338 (5).jpg
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  • Adjustable-Voltage-Regulator-using LM338 (6).jpg
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  • LM338 charger.jpg
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Schematic looks fine altho it's missing a bridge rectifier and a smoothing cap on the input.

C1 could have gone bad and creating problems. Otherwise the culprit is likely the LM338.
 
Schematic looks fine although it's missing a bridge rectifier and a smoothing cap on the input.

C1 could have gone bad and creating problems. Otherwise the culprit is likely the LM338.
Thanks, any clue as to what that chopped off blue wire might have been for? maybe the original positive in on the other side of the electrolytic?
And isn't the Blue electrolytic the smoothing capacitor?
As you can tell not my area of expertise.
 
We have an electronics repair guy not too far from here, just wanted to confirm I hadn't done any stoopid before I went that route.
 
All fixed thanks to ajw22 on Second life Storage, mystery blue wire (on pin 2 after cap) was - Ground, deleted the black wire to pin 1.
 

Attachments

  • LM338 charger.jpg
    LM338 charger.jpg
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