output from L78MR05 significantly off?

[tab a]

I'm working on the power supply in a Toshiba TV (TP4688J) and have found that the 5v supply, from an L78MR05 (Q840) is slightly high--5.27v--at both the output pins. As I read the datasheet, max output is supposed to be 5.2 Vo1, or 5.25 at Vo2.

Is that .07v enough to make a difference? (It's apparently been replaced at least once in the past.) Or should I look further to explain my dead power supply? (I know there is a leaking cap off VR Q801 but haven't found anything else).

Thanks.

 

[Roff]

When you post a question for a part, you should post a link to the **broken link removed**.
Vo2 is not the "second" output. It is the regulator's output voltage, specified over a wide input voltage and load current range. Vo1 is that same output, specified at 10V in and 0.35A load.
The reset output is strictly a logic level signal that can be used as a reset signal for microcontrollers, microprocessors, etc.
5.27V should not cause a problem. Are you sure your meter is accurate?

 

[Speakerguy]

Cheap 7805's are crap. 5.3V wouldn't surprise me. It's probably not a problem.

TI makes some accurate ones, TL780-05. They are good.

 

[tab a]

<Are you sure your meter is accurate?>

No, but it is a Fluke.

Thanks for the info on Vo1 and 2, and the advice!

 

[mvs sarma]

Fluke also can give FLUKE readings, after all aging is something.- the calibration can go off

 

[Speakerguy]

It's pretty rare with flukes though. We check cal on ours against a 6.5 digit bench top multimeter, the flukes are the only ones that hold cal well. They're several years old.