[intlplby]

ok... i built my TEPS and it was working fine.... had an output of 31.5 V and i accidentally shorted the output and now the TEPS is not working anymore....

it is still reading 39V at test points 1 and 2 and it is reading 54V at Test Points 3 and 5 but at test points 4 and 5 it is 0V and the LED is not lit up...

what part did i fry and i have to replace?

 

[MisterX]

Prolly cooked the regulator.
Which one did you use?
The standard LM317?

 

[intlplby]

yup lm317

anything else, or should just that fix it.... anyway to confirm that is the problem before i order parts



is there a way to prevent a problem like that from occuring again?
like a fuse or something

 

[MisterX]

Radio Shack does stock LM317t's.

Good question about if that is really the problem or not.
Because D3, C7 and C8 could also cause the same symptom if they shorted.
How much of the PSU do you want to tear apart is the big question.

 

[intlplby]

i'll just go ahead and order all those parts just to be on the safe side and try one at a time

thanks

drew

 

[peranders]

Many of those 3-pin regulators aren't certainly not indestructable even if the datasheet points in that direction.

 

[intlplby]

yeah, but if i am getting a good reading from test points 3 and 5 but not 4 and 5 doesn't that mean that those are OK?

 

[greyhorse]

Quote:

Originally Posted by peranders Many of those 3-pin regulators aren't certainly not indestructable even if the datasheet points in that direction.

So you're saying they ARE indestructable right?

-Sorry, I think we all know what you were trying to say, but I couldn't resist. Do they use a lot of double negatives in Swedish BTW?

intlplby, yes you can use a fuse in the future to prevent the same thing from happening. I usually use the very scientific method of using consecutively smaller fuses until either the fuse blows, or I run out of smaller fuses. In most headphone amplifier applications, the latter happens most often. TEPS has some degree of soft-starting, so you should be able to use fairly small fuses without problem.

 

[tangent]

Quote:

if i am getting a good reading from test points 3 and 5 but not 4 and 5 doesn't that mean that those are OK?

The first tests the voltage before the regulator, the second tests the voltage after the regulator. So, the regulator section would seem to be at fault.

Quote:

So you're saying they ARE indestructable right?

No....he's saying they are destructible. And I concur.

 

[intlplby]

well i hope those are ok since i already placed my order with mouser.......

 

[intlplby]

i had to run an errand and was near a Rat Shack so i picked up an LM317t and that fixed it .


hooked it up to my PPA with DynoBias that i finished troubleshooting this afternoon ....

measured DC offset one last time..... tried crappy phones then my HP-1's......

hot diggity dog.... this sounds incredible... much better than my Pimeta....

I listened to the Box of Matches recording and this is the first time i was able to discern the sound in front of me and not just behind..... up and down resolution was clearer as well.....

now i just need to wait for my hammond enclosure to arrive in 2 days (bass boost caps and switches too).....unfortunately i forgot to add the resistors for the battery board and i got to sort that out and order them as well.

i still need to sit down and properly adjust the DynoBias and the PPA trimpots...... perhaps i'll throw my cross feed board together later