On Mon, 16 May 2005 22:15:33 +0200, Sander deWaal
wrote:

said:

Sounds like a more involved process than I imagined. Is there a
typical issue that would cause the rail fuses to blow? I should
probably pop the cover and look inside. Perhaps a wire simply came
loose when I moved it?


The original post is no longer on my server, so I have missed what the
actual problem is.

You could try to resolder the PCBs of the amp, IIRC this amp gets
rather hot in use so solder joints may have weakened.
Moving the amp may have disconnected a component's pin from the PCB.
You can do this yourself or ask someone who's skilled with a soldering
iron.
Don't use lead-free solder (RoHS-compliant) because the old PCB wasn't
soldered with lead free solder. This may cause problems in the future.

That, and indeed maybe some loose wire somewhere.

Thanks.......I moved the amplifier to another cabinet, and when I
powered it back up, there was a loud hum out of the left channel.....I
subsequently found that one of the rail fuses had blown...I replaced
both fuses, powered the unit up, and it blew both fuses for the left
channel rail........

I guess it wouldn't hurt to pull the cover off and take a look
inside.....

said:

Thanks.......I moved the amplifier to another cabinet, and when I
powered it back up, there was a loud hum out of the left channel.....I
subsequently found that one of the rail fuses had blown...I replaced
both fuses, powered the unit up, and it blew both fuses for the left
channel rail........


Hm.....can't be much wrong there, i'd say ;-)


I guess it wouldn't hurt to pull the cover off and take a look
inside.....


Be sure to pull the plug beforehand!

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

"Sander deWaal" wrote in message
...
said:

Thanks.......I moved the amplifier to another cabinet, and when I
powered it back up, there was a loud hum out of the left channel.....I
subsequently found that one of the rail fuses had blown...I replaced
both fuses, powered the unit up, and it blew both fuses for the left
channel rail........


Hm.....can't be much wrong there, i'd say ;-)

One particular Hafler, a DH-120, had a design error.
The bias was derived from a string of power resistors that ran too hot.
When the lower resistor opened up, it would turn the outputs all the way on,
blowing the rail fuses.
No other Hafler has/had this design error.