If you pull out J208, does +10V recover? As Chuck said +10V is the reference to rest of the blocks. It could be low because of detecting a fault, removing J208 disables fault detection for +10V.
If after removing J208, +10V is still low check 2.5V reference. +15V unregulated looks high enough to run the 2.5 reference, you should see the same +15V unregulated voltage at pin1 of U1290, and 2.5V at pin 2.
Ozan
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On Sun, Dec 4, 2022 at 07:06 PM, Craig Cramb wrote:
2465B S/N B077993
Inverter card 670-7282-12
Regulator 670-7281-08
Previous repairs unknown.
Looking into a power supply that is basically non- functional on some voltages. I have removed it from the scope and connected it to power supplies loading assembly that was built by Jerry Massengale. This is perfect for checking power supply and have used it over the years. But now I¡¯m stuck and cannot seem to see what is causing low voltage from supplies to be out of tolerance.
+87= 60vdc
+42= 19.92vdc
-15VU=-17.80vdc
+10=0.113vdc
+5VD=+4.13vdc
+5=3.3vdc
-5=-2.8vdc
-15=-1.47vdc
-8=-2.15vdc
+15=+2.58vdc
I looked into the inverter troubleshooting and built myself a +5VD primary test load and then went back to inverter troubleshooting and decided this isn¡¯t going to help me as it seems to stop at +10vdc.
I went thru and checked the unregulated voltages at
J234b side. 1=-17vdc,2=-6.3vdc,3=gnd,4=+6.3vdc, 5=+17.3 (All a little low by 2vdc)
J233b side. 1=-6.2vdc,2=+17.2,3=+48,4=Gnd,5=+90.8. (These seem close a bit high but 1=6.2vdc is way high as per schematic)
This is where I¡¯m at right now. If anyone would like to make any suggestions it would be greatly appreciated.
Craig Cramb
