Author Topic: Odd output from Elenco XP-15K Power Supply - Schematic  (Read 316 times)

0 Members and 1 Guest are viewing this topic.

Offline tomherrick

  • Contributor
  • Posts: 19
  • Country: us
Odd output from Elenco XP-15K Power Supply - Schematic
« on: January 21, 2019, 10:58:50 am »
Schematic of XP-15K.
« Last Edit: January 21, 2019, 11:01:47 am by tomherrick »
 

Offline tpowell1830

  • Frequent Contributor
  • **
  • Posts: 719
  • Country: us
Re: Odd output from Elenco XP-15K Power Supply - Schematic
« Reply #1 on: January 21, 2019, 12:16:16 pm »
Hi Tom, you can find your original post by going to the menu above and clicking Profile and then Show Posts. This belongs with your original post.
PEACE===>T
 

Offline rstofer

  • Super Contributor
  • ***
  • Posts: 5535
  • Country: us
Re: Odd output from Elenco XP-15K Power Supply - Schematic
« Reply #2 on: January 21, 2019, 01:02:35 pm »
Right, add the schematic as an attachment to the other post and then delete this post (if possible).
It's kind of a PITA to flip between two threads to try to follow the schematic versus the PCB images.
 

Offline rstofer

  • Super Contributor
  • ***
  • Posts: 5535
  • Country: us
Re: Odd output from Elenco XP-15K Power Supply - Schematic
« Reply #3 on: January 21, 2019, 01:16:00 pm »
Diodes D5 and D6 make up a poor man's zener diode and the voltage between ground and the point where the diode connects to R4 should read -1.4, give or take.  Black wire of you meter goes on ground.  This negative voltage is what allows the regulator to get down to 0V.

I don't know the AC voltage between the blue and yellow wires of the transformer but about 1.4 times that value should be measured at pin 3 of the LM317 as a DC voltage.

Pin 1 of the LM317 should move between some negative value, like -1.4V, up to some positive value, nearly 15V,  but I haven't calculated the exact range.

 

Online Simon

  • Global Moderator
  • *****
  • Posts: 12730
  • Country: gb
  • Did that just blow up? No? might work after all !!
    • Simon's Electronics
Re: Odd output from Elenco XP-15K Power Supply - Schematic
« Reply #4 on: January 21, 2019, 08:21:23 pm »
Please refer to: http://www.eevblog.com/forum/beginners/odd-output-from-elenco-xp-15k-power-supply/
Tomherrik, this forum does not work like this, you need to post in the original topic or you will just have a bunch of unrelated and unintelligible posts floating around that no one can decipher. You can also edit your post if you want to add information.
https://www.simonselectronics.co.uk/shop
Varied stock of test instruments and components including EEVblog gear.
Also, if you want to get ripped off: https://www.ebay.co.uk/usr/simons_electronics?_trksid=p2047675.l2559
 
The following users thanked this post: tomherrick


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf