EEVblog #538 - HP35670A DSA Repair - Part 2

• #50 Reply
  Posted by Stonent on 25 Oct, 2013 23:43
• Quote from: EEVblog on 25 Oct, 2013 21:50

  Quote from: Stonent on 25 Oct, 2013 20:23

  Well he did on their forum, but that was towards the time of the first video, they redirected him to the PSU area and he got no responses.
  

  
  Why they moved it to the PSU area just baffles me.
  But in any case, it looks like the schematics are unobtainium.
  

  
  Well I guess because initially you were trying to get it to power up so perhaps that's why. Maybe a new posting about the A5 board will get some more hits?
• #51 Reply
  Posted by k2teknik on 27 Oct, 2013 07:53
• Quote from: EEVblog on 25 Oct, 2013 21:50

  But in any case, it looks like the schematics are unobtainium.
  

  I think that HP / Agilent just not have the copyright to publish the schematic, you get that message now and then when you ask for schematic, drivers and other tech questions, the answer goes like, "Sorry we can't give you that because of copyright".
  They buy a finish product, branded in there own name, and a part of the "low" price is the missing copyright to publish the schematic etc.
• #52 Reply
  Posted by k2teknik on 27 Oct, 2013 07:58
• Quote from: Galaxyrise on 25 Oct, 2013 19:41

  You showed a chart of measured power supply voltages, and that got me thinking.  When checking a "maybe bad" power supply, when do you check with a scope and not just a DMM?
  

  For good measure you can add in a scope and one more DMM, then you can measure AC, DC and see the scope picture, all at the same time, and you should do it every time, but we are just human ain't we?
• #53 Reply
  Posted by EEVblog on 27 Oct, 2013 08:03
• Quote from: k2teknik on 27 Oct, 2013 07:53

  They buy a finish product, branded in there own name, and a part of the "low" price is the missing copyright to publish the schematic etc.
  

  
  There is no way this is not a 100% designed HP product (excluding PSU)
• #54 Reply
  Posted by alm on 27 Oct, 2013 14:36
• If this product was repaired by board exchange in the service centers and they didn't offer a CLIP, then schematics may very well never have existed outside the product development department.
• #55 Reply
  Posted by Fitzroy on 02 Nov, 2013 12:52
• Hey Dave at around 7 mins into the video. You said there was two 5 V rails one being 5V analog and the other being being 5V Digital. So what is difference between those two(other being called digital and Analog)
  
  Thanks
   
• #56 Reply
  Posted by daddario on 02 Nov, 2013 15:48
• Quote from: Fitzroy on 02 Nov, 2013 12:52

  Hey Dave at around 7 mins into the video. You said there was two 5 V rails one being 5V analog and the other being being 5V Digital. So what is difference between those two(other being called digital and Analog)
  
  Thanks
  

  
  This is usually done to minimise noise ingress to the analog part from the digital part.