Re: 7904 Mainframe damaged


JJ
 

All the resistances with the PSU disconnected from the mainframe are way
higher than those indicated in the "Servicing the 7904 High-efficiency PS"
doc. When I fix the issues that I have found and the resistance
measurements line up with that doc, then I should be good to reconnect the
PSU to the mainframe,

On Tue, Apr 10, 2018 at 10:22 AM, Velik Kazakov via Groups.Io <
velik_kazakov=yahoo.com@groups.io> wrote:

On Tue, Apr 10, 2018 at 04:16 am, JJ wrote:


Dave, I went through hundreds of files in the files section of the
archive
and wasn't able to identify the schematic describing the minimum loading
requirements for power supplies. Tried searching, browsing, ad nauseum!
No
glory. Are you sure that Jerry uploaded it?

Best,
John
There have nothing about minimum load, but in the "Servicing the 7904
High-efficiency PS" have the resistance for all of power rails. You can to
calculate the load but, need to make some for all of rails. I do some of
this scopes and first measuring the main frame and when all is in limits
connect the PS to main frame and check all in PS. I find lots of bad caps
in all the boards in the main frame before to start to do the power supply.
If need can try to find a topic in the eevblog for one of this scopes.



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