red light fixed but not fixed

Huggybear

Vu+ Newbie
hello everyone,
ok, same problem as everyone. only mine was a bit more severe, as in, the regulator fried. so i got replacements off ebay, had a good read of the problem, worked out what to do and replaced the three capacitors, C807, C814 and C850. then replaced the burnt out regulator (U801). coundn't work out the number on that one because it was fried from the top (i understand the original number is AZ1021), but the replaced one was numbered Z1021HAI with the number ZA1023 underneath it.
but now the problem seems to be the PSU, or at least it seemed at first. checked voltage output at the white connector to the motherboard and had no reading whatsoever. no 5v no 3v or no 12v. the hhd connector showed a little voltage but nothing what it should be. so replaced PSU with another one from my other working box (both Vu+ Duo), and had the same result. no output at the connector. how can that be? i put the first PSU (from the fried regulator box) into my other working box and it is working fine. the box is working as i am writing this post.
can some expert suggest what might be the problem, and tell me what to check next? everyone else says that replacing the capacitors and/or the regulators gets the box working again. but obviously not in my case.

thanks in advance and apologies for the very long post.
 

makbar

Vu+ Newbie
most likely that the problem is on the pcb side, which you have varified by swapping the psu's.
you can disconnect every thing going to pcb i.e every connector.
then just connect psu to pcb, and measure voltage just in case something is dragging the voltage down.
If the power is there with nothing connected, then reconnect 1 at time and see which is the faulty part.
making sure switch off while do this process.
also check the polarity of the caps you replaced.
if still no power then switch off
using dvm(digital volt meter) on resistance range check all supplies with respect to ground.

hope this help good luck
 

Huggybear

Vu+ Newbie
thanks for that Makbar,
ok, the problem i have is this. as explained above, even without connecting anything from the psu to the mainboard via the white connector, should there be a reading of different voltage on the output of the white connector, viz: 2x 3v, 4x 5v, 1x 12v and 1x 34v. if not then why not. if so, then how come the working psu didn't show any voltage?
thanks
 

lefrance

Vu+ Newbie
Hello,
I had the same problem (only the red led).
I had the tensions 5v 12v 3.3v ...
And then more than the first 5v and more red led
I replaced the u801 and the 200μ (it was only 70μ).

Still no red led!
 
Top