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uk.rec.audio (General Audio and Hi-Fi) (uk.rec.audio) Discussion and exchange of hi-fi audio equipment.

Bit of luck for once.



 
 
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  #1 (permalink)  
Old December 22nd 17, 10:11 AM posted to uk.rec.audio
Dave Plowman (News)
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Posts: 5,872
Default Bit of luck for once.

My ancient workshop amp failed. Took the mains fuse - and a replacement.
It was assembled from bits I had lying around - including a mains
transformer I've not quite sure what it was made for. And of course it's
always the most expensive bit that fails...

Turned out to be the rectifier. Nice cheap fix - had a spare.

--
*Windows will never cease *

Dave Plowman London SW
To e-mail, change noise into sound.
  #2 (permalink)  
Old December 22nd 17, 01:30 PM posted to uk.rec.audio
Brian Gaff
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Posts: 637
Default Bit of luck for once.

I remember back in the days of the first vcrs. A Philips 1501 would cut out
for no apparent reason. In the end after much messing about running it with
the bottom hinged down, two Mullard rectifiers were removed from the pcb and
found to have lose wires in the green/blue mouldings on one end I took out
the other two as well and replaced them with an assortment of reclaimed
rectifiers culled from old junked gear and never another problem. It seems
to me that when companies first started to encapsulate things the movement
under heating and cooling over time was a common failure mode Since then
before I lost my sight, I have had cause to change these Byxxx rectifiers
many times in equipment.
This component will self destruct in 4 years.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Dave Plowman (News)" wrote in message
...
My ancient workshop amp failed. Took the mains fuse - and a replacement.
It was assembled from bits I had lying around - including a mains
transformer I've not quite sure what it was made for. And of course it's
always the most expensive bit that fails...

Turned out to be the rectifier. Nice cheap fix - had a spare.

--
*Windows will never cease *

Dave Plowman
London SW
To e-mail, change noise into sound.



  #3 (permalink)  
Old December 22nd 17, 02:13 PM posted to uk.rec.audio
Dave Plowman (News)
external usenet poster
 
Posts: 5,872
Default Bit of luck for once.

In article ,
Brian Gaff wrote:
I remember back in the days of the first vcrs. A Philips 1501 would cut
out for no apparent reason. In the end after much messing about running
it with the bottom hinged down, two Mullard rectifiers were removed from
the pcb and found to have lose wires in the green/blue mouldings on one
end I took out the other two as well and replaced them with an
assortment of reclaimed rectifiers culled from old junked gear and never
another problem. It seems to me that when companies first started to
encapsulate things the movement under heating and cooling over time was
a common failure mode Since then before I lost my sight, I have had
cause to change these Byxxx rectifiers many times in equipment. This
component will self destruct in 4 years.


It does seem to be one of the less common failures I've come across here,
though.

Could well be my fault - no thermal paste to the case. But then this amp
is hardly ever driven hard.

--
*Why isn't there mouse-flavoured cat food?

Dave Plowman London SW
To e-mail, change noise into sound.
  #4 (permalink)  
Old December 23rd 17, 07:34 AM posted to uk.rec.audio
Brian Gaff
external usenet poster
 
Posts: 637
Default Bit of luck for once.

I do think that equipment being run well within its capabilities is why
things last. I have a Denon amp here, well its a receiver, but it has never
generated anything but barely warm heat pip fed heat sinks.
The only problems I've encountered are relay contacts that need a clean
now and again on the speaker circuit. However A Marantz supposedly the same
output power, gets hot especially around the heat sink and some of the
digital control bits and the latter seems to have malfunctioned and is now
stuck on two inputs and no way to switch in the tone controls. Bad bit of
design making hot things very close to each other. I'm told its not worth
fixing as they all end up toast in the end.
On the other hand as I've said here before, my very 1stRogers valve amp
still works, needs perhaps some new capacitors , but has only ever needed a
balance control and a mains switch since new in 1966.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Dave Plowman (News)" wrote in message
...
In article ,
Brian Gaff wrote:
I remember back in the days of the first vcrs. A Philips 1501 would cut
out for no apparent reason. In the end after much messing about running
it with the bottom hinged down, two Mullard rectifiers were removed from
the pcb and found to have lose wires in the green/blue mouldings on one
end I took out the other two as well and replaced them with an
assortment of reclaimed rectifiers culled from old junked gear and never
another problem. It seems to me that when companies first started to
encapsulate things the movement under heating and cooling over time was
a common failure mode Since then before I lost my sight, I have had
cause to change these Byxxx rectifiers many times in equipment. This
component will self destruct in 4 years.


It does seem to be one of the less common failures I've come across here,
though.

Could well be my fault - no thermal paste to the case. But then this amp
is hardly ever driven hard.

--
*Why isn't there mouse-flavoured cat food?

Dave Plowman
London SW
To e-mail, change noise into sound.



 




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