Hummmmmmmmmmmmmmmmm...
 

I suppose this is more repair than homebrew, but since at least it's in the right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. The ham antennas were disconnected so the ham gear survived, but some of my computer &
consumer gear wasn't so lucky.

In particular, a Sony XDR-F1HD HD Radio tuner.

It actually works fine. However, there's about 600mV of AC between ground and the shield sides of the audio output and antenna input jacks. As you
might guess, this leads to a bit of a hum problem!

Suspected leakage across the power transformer (between primary & secondary) but I'm not finding any with an ohmmeter. There's absolutely *nothing*
on the primary side of the transformer except the power cord -- no capacitors to ground, nothing like that. Silk-screen on the power supply board
does say there's a fuse *inside* the transformer but obviously that's not going to be a source of a ground fault.

I'm confident the fault is in the Sony (and not the audio amplifier or a damaged antenna cable) since if I connect the same audio cables and antenna
to the old analog tuner it works fine.

Anyone have any good ideas where to look?

I guess I could:

- Come up with an isolation transformer & just run it that way. (it only draws 13 watts)
- Build up an external power supply. It only needs +5.2 and +10.5V unregulated, and the connection points are silk-screened on the board.
- Live with it & just kick in the high-pass filter. (and use the analog tuner if I want to listen to a program -- the Sony is for DXing..)

--

Doug Smith W9WI
Pleasant View, TN EM66

Hummmmmmmmmmmmmmmmm...
 

On Jun 5, 11:36*am, sorry-spammers ""w9wi\"@(sorry-spammers)" wrote:
t

- Live with it & just kick in the high-pass filter. *(and use the analog tuner if I want to listen to a program -- the Sony is for DXing..)

--

Doug Smith W9WI
Pleasant View, TN *EM66



Hey OM:

I know you got a screw loose there for sure.
Back in the day I used to make a living repairing Sony product's
All the Techs' in the shop would kill to get their hands on an easy
fix Sony
I fixed many a Sony audio product just by tightening all the chassis's
screws
There was a service flash for that trouble so it was real.


73 OM
de n8zu

Hummmmmmmmmmmmmmmmm...
 

On Sat, 05 Jun 2010 10:36:36 -0500, sorry-spammers wrote:

I suppose this is more repair than homebrew, but since at least it's in
the right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. The ham
antennas were disconnected so the ham gear survived, but some of my
computer & consumer gear wasn't so lucky.

In particular, a Sony XDR-F1HD HD Radio tuner.

It actually works fine. However, there's about 600mV of AC between
ground and the shield sides of the audio output and antenna input jacks.
As you might guess, this leads to a bit of a hum problem!

Suspected leakage across the power transformer (between primary &
secondary) but I'm not finding any with an ohmmeter. There's absolutely
*nothing* on the primary side of the transformer except the power cord
-- no capacitors to ground, nothing like that. Silk-screen on the power
supply board does say there's a fuse *inside* the transformer but
obviously that's not going to be a source of a ground fault.

I'm confident the fault is in the Sony (and not the audio amplifier or a
damaged antenna cable) since if I connect the same audio cables and
antenna to the old analog tuner it works fine.

Anyone have any good ideas where to look?

I guess I could:

- Come up with an isolation transformer & just run it that way. (it
only draws 13 watts) - Build up an external power supply. It only needs
+5.2 and +10.5V unregulated, and the connection points are silk-screened
on the board. - Live with it & just kick in the high-pass filter. (and
use the analog tuner if I want to listen to a program -- the Sony is for
DXing

I would suggest temporally swapping out the xformer with something
comparable or remove the xformer from the radio and see if it has leakage
outside the radio. (assuming it's not a switching supply)

Hummmmmmmmmmmmmmmmm...
 

On Jun 5, 11:36*am, sorry-spammers ""w9wi\"@(sorry-spammers)" wrote:
I suppose this is more repair than homebrew, but since at least it's in the right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. *The ham antennas were disconnected so the ham gear survived, but some of my computer &
consumer gear wasn't so lucky.

In particular, a Sony XDR-F1HD HD Radio tuner.

It actually works fine. *However, there's about 600mV of AC between ground and the shield sides of the audio output and antenna input jacks. *As you
might guess, this leads to a bit of a hum problem!

Suspected leakage across the power transformer (between primary & secondary) but I'm not finding any with an ohmmeter. *There's absolutely *nothing*
on the primary side of the transformer except the power cord -- no capacitors to ground, nothing like that. *Silk-screen on the power supply board
does say there's a fuse *inside* the transformer but obviously that's not going to be a source of a ground fault.

I'm confident the fault is in the Sony (and not the audio amplifier or a damaged antenna cable) since if I connect the same audio cables and antenna
to the old analog tuner it works fine.

Anyone have any good ideas where to look?

I guess I could:

- Come up with an isolation transformer & just run it that way. *(it only draws 13 watts)
- Build up an external power supply. *It only needs +5.2 and +10.5V unregulated, and the connection points are silk-screened on the board.
- Live with it & just kick in the high-pass filter. *(and use the analog tuner if I want to listen to a program -- the Sony is for DXing..)

--

Doug Smith W9WI
Pleasant View, TN *EM66

First thing I would do is check my cables, sounds like you have an
open ground or a ground loop among other possible problems listed. Why
do this first? Its EZ.

Jimmie

Hummmmmmmmmmmmmmmmm...
 

On Jun 5, 11:36*am, sorry-spammers ""w9wi\"@(sorry-spammers)" wrote:
I suppose this is more repair than homebrew, but since at least it's in the right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. *The ham antennas were disconnected so the ham gear survived, but some of my computer &
consumer gear wasn't so lucky.

In particular, a Sony XDR-F1HD HD Radio tuner.

It actually works fine. *However, there's about 600mV of AC between ground and the shield sides of the audio output and antenna input jacks. *As you
might guess, this leads to a bit of a hum problem!

Suspected leakage across the power transformer (between primary & secondary) but I'm not finding any with an ohmmeter. *There's absolutely *nothing*
on the primary side of the transformer except the power cord -- no capacitors to ground, nothing like that. *Silk-screen on the power supply board
does say there's a fuse *inside* the transformer but obviously that's not going to be a source of a ground fault.

I'm confident the fault is in the Sony (and not the audio amplifier or a damaged antenna cable) since if I connect the same audio cables and antenna
to the old analog tuner it works fine.

Anyone have any good ideas where to look?

I guess I could:

- Come up with an isolation transformer & just run it that way. *(it only draws 13 watts)
- Build up an external power supply. *It only needs +5.2 and +10.5V unregulated, and the connection points are silk-screened on the board.
- Live with it & just kick in the high-pass filter. *(and use the analog tuner if I want to listen to a program -- the Sony is for DXing..)

--

Doug Smith W9WI
Pleasant View, TN *EM66

First thing I would do is check my cables, sounds like you have an
open ground or a ground loop among other possible problems listed. Why
do this first? Its EZ.

Jimmie

Hummmmmmmmmmmmmmmmm...
 

JIMMIE wrote:
On Jun 5, 11:36 am, sorry-spammers ""w9wi\"@(sorry-spammers)" wrote:
I suppose this is more repair than homebrew, but since at least it's in the right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. The ham antennas were disconnected so the ham gear survived, but some of my computer &
consumer gear wasn't so lucky.

In particular, a Sony XDR-F1HD HD Radio tuner.

It actually works fine. However, there's about 600mV of AC between ground and the shield sides of the audio output and antenna input jacks. As you
might guess, this leads to a bit of a hum problem!

Suspected leakage across the power transformer (between primary & secondary) but I'm not finding any with an ohmmeter. There's absolutely *nothing*
on the primary side of the transformer except the power cord -- no capacitors to ground, nothing like that. Silk-screen on the power supply board
does say there's a fuse *inside* the transformer but obviously that's not going to be a source of a ground fault.

I'm confident the fault is in the Sony (and not the audio amplifier or a damaged antenna cable) since if I connect the same audio cables and antenna
to the old analog tuner it works fine.

Anyone have any good ideas where to look?

I guess I could:

- Come up with an isolation transformer & just run it that way. (it only draws 13 watts)
- Build up an external power supply. It only needs +5.2 and +10.5V unregulated, and the connection points are silk-screened on the board.
- Live with it & just kick in the high-pass filter. (and use the analog tuner if I want to listen to a program -- the Sony is for DXing..)

--

Doug Smith W9WI
Pleasant View, TN EM66

First thing I would do is check my cables, sounds like you have an
open ground or a ground loop among other possible problems listed. Why
do this first? Its EZ.

Jimmie


Between you, me, y'all and the fencepost I'd look for basic PS
problems and not focus on the "600mV of AC between ground and the shield
sides of the audio output and antenna input jacks".

-Bill

Hummmmmmmmmmmmmmmmm...
 

On Jun 6, 11:12*pm, Bill M wrote:
JIMMIE wrote:
On Jun 5, 11:36 am, sorry-spammers ""w9wi\"@(sorry-spammers)" wrote:
I suppose this is more repair than homebrew, but since at least it's in the right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. *The ham antennas were disconnected so the ham gear survived, but some of my computer &
consumer gear wasn't so lucky.

In particular, a Sony XDR-F1HD HD Radio tuner.

It actually works fine. *However, there's about 600mV of AC between ground and the shield sides of the audio output and antenna input jacks. *As you
might guess, this leads to a bit of a hum problem!

Suspected leakage across the power transformer (between primary & secondary) but I'm not finding any with an ohmmeter. *There's absolutely *nothing*
on the primary side of the transformer except the power cord -- no capacitors to ground, nothing like that. *Silk-screen on the power supply board
does say there's a fuse *inside* the transformer but obviously that's not going to be a source of a ground fault.

I'm confident the fault is in the Sony (and not the audio amplifier or a damaged antenna cable) since if I connect the same audio cables and antenna
to the old analog tuner it works fine.

Anyone have any good ideas where to look?

I guess I could:

- Come up with an isolation transformer & just run it that way. *(it only draws 13 watts)
- Build up an external power supply. *It only needs +5.2 and +10.5V unregulated, and the connection points are silk-screened on the board.
- Live with it & just kick in the high-pass filter. *(and use the analog tuner if I want to listen to a program -- the Sony is for DXing..)

--

Doug Smith W9WI
Pleasant View, TN *EM66

First thing I would do is check my cables, sounds like you have an
open ground or a ground loop among other possible problems listed. Why
do this first? Its EZ.

Jimmie

* Between you, me, y'all and the fencepost *I'd look for basic PS
problems and not focus on the "600mV of AC between ground and the shield
sides of the audio output and antenna input jacks".

-Bill

The question is " should these two points be at ground or not. If they
are I would have to best guess that something got popped in the
antenna input.

Jimmie

Hummmmmmmmmmmmmmmmm...
 

"sorry-spammers" ""w9wi\"@(sorry-spammers)" wrote in message
m...
I suppose this is more repair than homebrew, but since at least it's in the
right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. The ham antennas
were disconnected so the ham gear survived, but some of my computer &
consumer gear wasn't so lucky.
sinp

Many PC Board designs incorporate 'thin' foil paths that are intentionally
used as fuses... linking an input ground foil group to a power supply foil
group is one such usage. The hit may have blown a trace that isn't
immediately visible.

I suffered the effects of a near by strike last year. The induced field
blew out a myriad of low-level input circuits on everything from wireless
phones, to the 1000BT inputs on my server, and 24 port switch, monitors...
not the P.S., remote ant tuners, on and on... Didn't loose a single power
supply or fuse. As a testament to ICOM engineering my IC-7800, at the time
connected to two antennas, suffered no damage. My Elecraft K2, connect to
a coax run that terminated at an outdoor antenna switch but was not
selected, came through OK too.

Hummmmmmmmmmmmmmmmm...
 

On Jun 7, 3:09*pm, "Hello.com" wrote:
"sorry-spammers" ""w9wi\"@(sorry-spammers)" wrote in message

m...I suppose this is more repair than homebrew, but since at least it's in the
right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. *The ham antennas
were disconnected so the ham gear survived, but some of my computer &
consumer gear wasn't so lucky.

sinp

Many PC Board designs incorporate 'thin' foil paths that are intentionally
used as fuses... *linking an input ground foil group to a power supply foil
group is one such usage. *The hit may have blown a trace that isn't
immediately visible.

I suffered the effects of a near by strike last year. *The induced field
blew out a myriad of low-level input circuits on everything from wireless
phones, to the 1000BT inputs on my server, and 24 port switch, monitors....
not the P.S., remote ant tuners, on and on... *Didn't loose a single power
supply or fuse. As a testament to ICOM engineering my IC-7800, at the time
connected to two antennas, suffered no damage. *My Elecraft K2, *connect to
a coax run that terminated at an outdoor antenna switch but was not
selected, came through OK too.

Lightning came do some pretty strange things to electronic equipment.
I once repaired a Radio Shack color computer that had 4 or 5 lines of
it data bus vaporized without damaging anything else. After the
damaged area was repaired with jumpers the computer worked fine. To me
the fact that the innards of this computer survived is as impressive
as the service panel that gets blown out of the wall and across the
room or the tree that is completely stripped of bark. The damage was
done directly beneath the uP chip.

Jimmie


Jimmie

Hummmmmmmmmmmmmmmmm...
 

On Jun 7, 3:09*pm, "Hello.com" wrote:
"sorry-spammers" ""w9wi\"@(sorry-spammers)" wrote in message

m...I suppose this is more repair than homebrew, but since at least it's in the
right spirit I hope you'll indulge me...

Took a lightning hit on the power line about a week ago. *The ham antennas
were disconnected so the ham gear survived, but some of my computer &
consumer gear wasn't so lucky.

sinp

Many PC Board designs incorporate 'thin' foil paths that are intentionally
used as fuses... *linking an input ground foil group to a power supply foil
group is one such usage. *The hit may have blown a trace that isn't
immediately visible.

I suffered the effects of a near by strike last year. *The induced field
blew out a myriad of low-level input circuits on everything from wireless
phones, to the 1000BT inputs on my server, and 24 port switch, monitors....
not the P.S., remote ant tuners, on and on... *Didn't loose a single power
supply or fuse. As a testament to ICOM engineering my IC-7800, at the time
connected to two antennas, suffered no damage. *My Elecraft K2, *connect to
a coax run that terminated at an outdoor antenna switch but was not
selected, came through OK too.

Lightning came do some pretty strange things to electronic equipment.
I once repaired a Radio Shack color computer that had 4 or 5 lines of
it data bus vaporized without damaging anything else. After the
damaged area was repaired with jumpers the computer worked fine. To me
the fact that the innards of this computer survived is as impressive
as the service panel that gets blown out of the wall and across the
room or the tree that is completely stripped of bark. The damage was
done directly beneath the uP chip.

Jimmie


Jimmie