Hola all,
I recently picked up two dead scopes in a job lot. One had missing and blown components as well as a toasted trace on the PSU, whereas the other was complete and not burnt.
Anyway, managed to get both PSU's working enough to switch the scopes on, with the LV rails all more less where they should be, and that is;
+140v
+8v
+5v
-8v
Minus 8v is the adjustable reference voltage, which actually doesn't seem to adjust on either PSU. There is a KMA 01 hybrid IC with a couple of op-amps in it which the voltages pass through.
The problems arise when the PSU is connected to the main board and immediately all the rails drop by around 20% or so.
I'm just wondering how to go about locating the problem? I have a millivolt meter but no working scope.
Would I be correct in thinking that considering how the fault is across all the rails and that all rails are dependent on the minus 8v, that this is where the problem should lie?
There are 37 electrolytics on each main board. I'm planning on testing them first.
Also enclosing the service manual, in case anyone wants a look...
Would be great to get these working.
I recently picked up two dead scopes in a job lot. One had missing and blown components as well as a toasted trace on the PSU, whereas the other was complete and not burnt.
Anyway, managed to get both PSU's working enough to switch the scopes on, with the LV rails all more less where they should be, and that is;
+140v
+8v
+5v
-8v
Minus 8v is the adjustable reference voltage, which actually doesn't seem to adjust on either PSU. There is a KMA 01 hybrid IC with a couple of op-amps in it which the voltages pass through.
The problems arise when the PSU is connected to the main board and immediately all the rails drop by around 20% or so.
I'm just wondering how to go about locating the problem? I have a millivolt meter but no working scope.
Would I be correct in thinking that considering how the fault is across all the rails and that all rails are dependent on the minus 8v, that this is where the problem should lie?
There are 37 electrolytics on each main board. I'm planning on testing them first.
Also enclosing the service manual, in case anyone wants a look...
Would be great to get these working.
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