What Did I Fry?
 

Bought a FT757GX on eBay. It came with the wrong cable.

The Operators Manual says the Jones connector should have two pins
jumpered, with nothing else normally applied there. Then plus 13.8V
and ground are applied to the other two pins.

This cable had plus 13.8 going to BOTH supply pins. Ground was
connected to both of the pins that were supposed to be jumpered.[1]

I learned this when I disassembled the Jones plug after smoke came out
of the rig.

I only have the Owners Manual, not the maintenance manual, so there's
no schematic to check.

If anybody has the schematic, what did that cable apply 13.8V across?
I haven't opened up the rig yet. Too annoyed.

Don NR7X
[1] Can anybody tell from that info what equipment this cable was
supposed to be connected to?

What Did I Fry?
 

"Don Tuite" wrote in message
...
Bought a FT757GX on eBay. It came with the wrong cable.

The Operators Manual says the Jones connector should have two pins
jumpered, with nothing else normally applied there. Then plus 13.8V
and ground are applied to the other two pins.

This cable had plus 13.8 going to BOTH supply pins. Ground was
connected to both of the pins that were supposed to be jumpered.[1]

I learned this when I disassembled the Jones plug after smoke came out
of the rig.

I only have the Owners Manual, not the maintenance manual, so there's
no schematic to check.

If anybody has the schematic, what did that cable apply 13.8V across?
I haven't opened up the rig yet. Too annoyed.

Don NR7X
[1] Can anybody tell from that info what equipment this cable was
supposed to be connected to?

These people have the service manuals:
http://www.mauritron.plus.com/html/y.html

I have some manuals for mine at home, don't recall off-hand if I have that
one but I'll check and see what is there. I recall circuit diagrams so if
no-one else has popped up by this afternoon I'll hunt it down (if I can find
it - I've shifted house recently :-(

Cheers.

Ken

What Did I Fry?
 

Thanks Ken. I don't want to pop for the manual unless the damage is
failrly limited. Obviously with +13.8 applied to both the high side
and ground most components were not stressed. The question is what
that jumper inside the Jones plug that got connected to the low side
of the supply is connected to inside the rig. The smell of the smoke
was characteristic of burnt circuit board, and there was a fair amount
of visible smoke.

Don NR7X

What Did I Fry?
 

"Don Tuite" wrote in message
...

Thanks Ken. I don't want to pop for the manual unless the damage is
failrly limited. Obviously with +13.8 applied to both the high side
and ground most components were not stressed. The question is what
that jumper inside the Jones plug that got connected to the low side
of the supply is connected to inside the rig. The smell of the smoke
was characteristic of burnt circuit board, and there was a fair amount
of visible smoke.

Don NR7X

I'm trying to remember, as it's been a long time since I had that rig out of
the box, but I recall that there's a reverse-polarity protection diode at
the input. The fuse should protect the board, but as normal I guess the
circuit board tracks protected it for a while. I'd be guessing that's the
starting point.

Cheers.

Ken

What Did I Fry?
 

If you have a place I can send you a 9.5 meg file , I have the service
manual in the PDF format I could send you.

"Don Tuite" wrote in message
...
Bought a FT757GX on eBay. It came with the wrong cable.

The Operators Manual says the Jones connector should have two pins
jumpered, with nothing else normally applied there. Then plus 13.8V
and ground are applied to the other two pins.

This cable had plus 13.8 going to BOTH supply pins. Ground was
connected to both of the pins that were supposed to be jumpered.[1]

I learned this when I disassembled the Jones plug after smoke came out
of the rig.

I only have the Owners Manual, not the maintenance manual, so there's
no schematic to check.

If anybody has the schematic, what did that cable apply 13.8V across?
I haven't opened up the rig yet. Too annoyed.

Don NR7X
[1] Can anybody tell from that info what equipment this cable was
supposed to be connected to?

What Did I Fry?
 

On Fri, 18 Nov 2005 17:54:24 GMT, "Ralph Mowery"
wrote:

If you have a place I can send you a 9.5 meg file , I have the service
manual in the PDF format I could send you.

Thank you kindly.

I sent you an email with a valid email address.

Don NR7X