Ashdown audio band amps - generic fault

[N Cook]

For factory retro-fitted fans.
3 faults in one just fitting a fan and power bleedoff

For random fan stoppage - look for
Instead of 47R 5W W/W placed in line with the fan (dangling R unsupported at
one end) , 0.047R soldered-in so 21V across the 12V fan. Surprisingly
thousands of hours of unproblematic use like that.

Even without that , for any long term excessive wear on the bearing of fan ,
the reaction force pushes the impeller towards the mounting bracket,
eventually touching it. You could see a slight trace of where one fan vane
had rubbed the bracket and rubbed the plastic of that vane, ie clear of
usual gunge.


Replace with 47R, supported, and new fan with the centre section of the
mounting bracket hacksawed out.

 

[N Cook]

For factory retro-fitted fans.
3 faults in one just fitting a fan and power bleedoff

For random fan stoppage - look for
Instead of 47R 5W W/W placed in line with the fan (dangling R unsupported at
one end) , 0.047R soldered-in so 21V across the 12V fan. Surprisingly
thousands of hours of unproblematic use like that.

Even without that , for any long term excessive wear on the bearing of fan ,
the reaction force pushes the impeller towards the mounting bracket,
eventually touching it. You could see a slight trace of where one fan vane
had rubbed the bracket and rubbed the plastic of that vane, ie clear of
usual gunge.


Replace with 47R, supported, and new fan with the centre section of the
mounting bracket hacksawed out.

Fourth mistake : the fan just circulates the air internally, no added
baffles to duct air in from outside.
So air heats up, softens fan's plastic vanes , vanes flex a bit, to the
extent of
touching the mount.

 

[Ron(UK)]

Fourth mistake : the fan just circulates the air internally, no added
baffles to duct air in from outside.
So air heats up, softens fan's plastic vanes , vanes flex a bit, to the
extent of
touching the mount.

What do you expect? it`s a Trashdown!



Ron

 

[N Cook]

What do you expect? it`s a Trashdown!



Ron

Up till today I assumed they were no better or no worse than any other make.

 

[N Cook]

What do you expect? it`s a Trashdown!



Ron

I was aware, a long time ago, that WEM was short for Works Every Monday

 

[N Cook]

I just thought of a fifth problem.
With the fan , as original, directing internal air down the long axis of the
fan. The big toroidal would split the air flow at the other end , returning
back to the fan along the outer edges.
As no pressure differential between inside and outside of box , the vents in
the base and rear become useless as any thermal gradient across the box is
lost.

A baffle now added arounfd the fan to take air from outside, through some of
the vents, and direct it back out through the remaining vents.