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Tek2465B power supply troubleshooting

 

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
 

Hi Craig,

I too have one of Jerry's loads. It works very well. I bought
it when I got tired of using clip leads and a couple of power
resistors.

The 10V supply is a very important reference voltage,
start there. If it is wrong, nothing else will be right.

-Chuck Harris


On Sun, 4 Dec 2022 21:06:20 -0600 "Craig Cramb"
<electronixtoolbox@...> 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




 

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


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
 

¿ªÔÆÌåÓý

Thank you Chuck and Ozan. I will continue dealing with the 10v circuit. ? I will be a little slow about working on it as my day job and family time seem to take up my spare time. ?I will continue updating so hopefully it will be useful to someone else dealing with this same type of issue.

Craig


On Dec 5, 2022, at 1:23 AM, Ozan <ozan_g@...> wrote:

?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


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
 

¿ªÔÆÌåÓý

With the previous readings I took and feedback back from Chuck and Ozan. ?I determined the problem wasn¡¯t on the inverter board but on the regulator board. Schematic 10. ? Checking out the points advised on the U1290, found the pin1=15vdc and pin2=2.48vdc without removing the J208.?
Did some additional checks on the +10volt Reference section as on the U1300 pin9=2.95v, pin10= 0.163vdc, pin8= 6.2vdc. ?So pin10 seems to be feedback from pin14 and it was at 0.16vdc I thought to look for something to ground. The first item on schematic was the VR1293. ?Did diode test and found it conducted both directions. ?Removed and checked same result. ?Happened to have the 152-0055-00 part. Installed and rechecked with power applied. All power supply voltages are as per the manual spec. Reinstalled in scope and operation is restored. ?Unsure what caused the VR1293 to fail but problem solved for now.?

Thanks for assistance!
Craig



On Dec 5, 2022, at 1:23 AM, Ozan <ozan_g@...> wrote:
A
?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


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
Aaron
 

Hi Craig,

Nice troubleshooting!

Aaron

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