dead podxt - repair help please :)

[big bustle]

my line6 podxt died a couple of months back. i opened it up today to look for obvious damage like burnt out components. i saw nothing obvious.

i tested the power supply and it's pushing 10v AC as expected. the on switch seems to be working as well according to a continuity test.

my first thought is somewhere the power section has died. so it would be ebst to make sure each transformer is putting out the specific volatages marked next to it

i see alot of 3 pronged items that are probably power transformers

marked on the board is

+15v
-15v
+5
+5va
+3.3v
+8v


how do i test these? touch my multimeter to ground and probe each pin?

[Processaurus]

Sure.

I doubt the "3 pronged items" are power transformers, since the AC adapter is the power transformer.

There aren't schematics publicly available unfortunately, maybe you can get a service manual on the black market.

[Ronsonic]

The only three legged gadgets I recall in there (bigger than a grain of rice anyway) are voltage regulators.

Yep, for the voltages, check between ground and the marked test points.

Each of those regulators will have a raw voltage in a ground reference and a regulated voltage out leg. So if you find a voltage missing you can look there.

Unfortunately you didn't say anything about what sort of problem you're having with the thing. Does it not power up? No boot? Power, boot, but no output?

Ron

[big bustle]

the pod itself is dead. no screen powers on. no LEDs. NUTTIN!

Yep, for the voltages, check between ground and the marked test points.

Each of those regulators will have a raw voltage in a ground reference and a regulated voltage out leg. So if you find a voltage missing you can look there.

what are marked test points?

i took my multimeter and probed each leg whilst connected to ground as well and got pretty much nothing. i wonder if there is a fuse somewhere i can't see.

[Ronsonic]

the pod itself is dead. no screen powers on. no LEDs. NUTTIN!

Yep, for the voltages, check between ground and the marked test points.

Each of those regulators will have a raw voltage in a ground reference and a regulated voltage out leg. So if you find a voltage missing you can look there.

what are marked test points?

i took my multimeter and probed each leg whilst connected to ground as well and got pretty much nothing. i wonder if there is a fuse somewhere i can't see.

Didn't you just say that there were places on the board with voltages indicated? That would constitute "marked" and would seem to be suitable "test points." Or I am completely misunderstanding you.


No DC at the regulators - Back up some more, Do you have power at the end of your adaptor?

Do you have it on the circuit board after the power inlet jack?

How about at the switch? After the switch? Do be sure you're looking for DC where appropriate and AC where it is supposed to be.

Start at the cord and work your way through.

Ron

[big bustle]

so....

let's see...

first of all sorry if i'm not so clear. it's only in hindsight do i realize i haven't mentioned something or spelled it out very clearly. i appreciate everyone's time in helping me out with this. i certainly don't want to make it more difficult for anyone 

let's start out with a picture shall we? i'm pasting a link only because the picture i huge. i've marked out in purple writing where the voltage regulators are.

http://fourthgradegladiators.com/test/gpix/boardpostpictures/podxt1.jpg

i connected the power supply and it reads 10v ac. i followed it to the leads past the switch. that reads 10v ac
i tested every lead to ground (case of podxt) with my DMM and they all say .196 v volts ac. in DC the values are around 40mV - 240mV.

so that's where i am now..

i guess the next step is find a schematic on the black market.. except there is no black market in my neighborhood. just a green market. if they have schematics along with organic veggies that would be pretty cool.

another step is to fullly take the thing out of it's case and see what's going on in the front so i can do a full trace of the power input section. these line 6 knobs are on pretty tight. iv'e had problems in the past gettin' them off and on with out completely f-ing up their finish.

my goal is to sell this thing on ebay as i am saving up for a p-bass. i don't even like the podxt all that much.


what do the voltage regulators do? do they take the 10v ac and convert them to the dc voltages needed to power the numerous chips?

[Ronsonic]

If you've got AC going in, but no DC at the regulators, your first suspect are the rectifier diodes that are supposed to do that conversion. Sorry, not all that familiar with that part of thecircuit.

Ron

[big bustle]

that sounds like a great idea! now if only i knew where the rectifier diodes were. i assume the markings on te board would start with a d?

[Ronsonic]

And they'll be in that neighborhood.

Ron