Ashdown Peacemaker P60 valve combo, 2003

N

N_Cook

Guest
I discovered how to get into it, remove front knobs etc and remove the facia
panel first.
This amp runs very hot in the region of the EL34 output valves, almost to
the
point of charring the pcb, localised black rather than just brown
discolouration. The valves are inverted and no ventillation path
under or around the valve bases. There is plenty of space to mill holes in
the pcb around the periphery, and avoiding traces, to allow some ventilltion
through. Anyone done this before or aware if it actually reduces localised
heat build-up ?


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
On Oct 18, 3:13 am, "N_Cook" <dive...@tcp.co.uk> wrote:
I discovered how to get into it, remove front knobs etc and remove the facia
panel first.
This amp runs very hot in the region of the EL34 output valves, almost to
the
point of charring the pcb, localised black rather than just brown
discolouration. The valves are inverted and no ventillation path
under or around the valve bases. There is plenty of space to mill holes in
the pcb around the periphery, and avoiding traces, to allow some ventilltion
through. Anyone done this before or aware if it actually reduces localised
heat build-up ?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list onhttp://home.graffiti.net/diverse:graffiti.net/
Click to expand...
You have demonstrated a good practical diagnosis many times here, go
for it. Too many of those amps were designed by engineers who never
got to se the final product in operation and had little or no common
sense.

Bob Hofmann
 
hr(bob) hofmann@att.net <hrhofmann@att.net> wrote in message
news:e9bbdda6-87cb-4ca3-a1a4-f49da3e17cbe@y79g2000hsa.googlegroups.com...
On Oct 18, 3:13 am, "N_Cook" <dive...@tcp.co.uk> wrote:
I discovered how to get into it, remove front knobs etc and remove the
facia
panel first.
This amp runs very hot in the region of the EL34 output valves, almost to
the
point of charring the pcb, localised black rather than just brown
discolouration. The valves are inverted and no ventillation path
under or around the valve bases. There is plenty of space to mill holes in
the pcb around the periphery, and avoiding traces, to allow some
ventilltion
through. Anyone done this before or aware if it actually reduces localised
heat build-up ?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list
onhttp://home.graffiti.net/diverse:graffiti.net/
Click to expand...

You have demonstrated a good practical diagnosis many times here, go
for it. Too many of those amps were designed by engineers who never
got to se the final product in operation and had little or no common
sense.

Bob Hofmann

Scraping back some of the pcb surface browning and into the bulk of the pcb
material , the browning extends the depth of the material. Also some brown
staining on the surface of nearby solder points, probably some vapour coming
off the polyester and settling on the solder. No ventillation grill in the
cabinet top either.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
Ancient_Hacker <grg2@comcast.net> wrote in message
news:a52402f3-1958-45f8-8c8c-0c703532e2e9@f63g2000hsf.googlegroups.com...
You might consider adding a small DC fan. A 12V fan running off a
diode and capacitor off the (supposed) 6.3VAC heaters will be running
relatively quietly at V.
Click to expand...

I'd half considered a fan but there is no obvious place to put it and
without cutting a hole in the steel chassis or the wood cabinet it would
just be circulating the air, unless mounted outside the chassis , directed
over the bottles. Good idea about the heater supply use.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
You might consider adding a small DC fan. A 12V fan running off a
diode and capacitor off the (supposed) 6.3VAC heaters will be running
relatively quietly at V.
 
N_Cook wrote:
Ancient_Hacker <grg2@comcast.net> wrote in message
news:a52402f3-1958-45f8-8c8c-0c703532e2e9@f63g2000hsf.googlegroups.com...
You might consider adding a small DC fan. A 12V fan running off a
diode and capacitor off the (supposed) 6.3VAC heaters will be running
relatively quietly at V.




I'd half considered a fan but there is no obvious place to put it and
without cutting a hole in the steel chassis or the wood cabinet it would
just be circulating the air, unless mounted outside the chassis , directed
over the bottles. Good idea about the heater supply use.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
Click to expand...
How about "tube coolers"? I've never used them, but if there's no room
for a fan... http://www.partsconnexion.com/audiogon_pix/WEBPAGES/PEARL.htm
 
In article <C2PKk.4677$yr3.2463@nlpi068.nbdc.sbc.com>,
Sofa Slug <sofaslug403spamnot@prodigy.net> wrote:

N_Cook wrote:
Ancient_Hacker <grg2@comcast.net> wrote in message
news:a52402f3-1958-45f8-8c8c-0c703532e2e9@f63g2000hsf.googlegroups.com...
You might consider adding a small DC fan. A 12V fan running off a
diode and capacitor off the (supposed) 6.3VAC heaters will be running
relatively quietly at V.




I'd half considered a fan but there is no obvious place to put it and
without cutting a hole in the steel chassis or the wood cabinet it would
just be circulating the air, unless mounted outside the chassis , directed
over the bottles. Good idea about the heater supply use.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/




How about "tube coolers"? I've never used them, but if there's no room
for a fan... http://www.partsconnexion.com/audiogon_pix/WEBPAGES/PEARL.htm
Click to expand...
They could get the heat away from the tubes, but it'd still be in the
box. By themselves, they'd probably make little difference.

Isaac
 
isw <isw@witzend.com> wrote in message
news:isw-D0858A.20485319102008@[216.168.3.50]...
In article <C2PKk.4677$yr3.2463@nlpi068.nbdc.sbc.com>,
Sofa Slug <sofaslug403spamnot@prodigy.net> wrote:

N_Cook wrote:
Ancient_Hacker <grg2@comcast.net> wrote in message

news:a52402f3-1958-45f8-8c8c-0c703532e2e9@f63g2000hsf.googlegroups.com...
You might consider adding a small DC fan. A 12V fan running off a
diode and capacitor off the (supposed) 6.3VAC heaters will be running
relatively quietly at V.




I'd half considered a fan but there is no obvious place to put it and
without cutting a hole in the steel chassis or the wood cabinet it
would
just be circulating the air, unless mounted outside the chassis ,
directed
over the bottles. Good idea about the heater supply use.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/




How about "tube coolers"? I've never used them, but if there's no room
for a fan...
http://www.partsconnexion.com/audiogon_pix/WEBPAGES/PEARL.htm

They could get the heat away from the tubes, but it'd still be in the
box. By themselves, they'd probably make little difference.

Isaac
Click to expand...

Unfortunately I cannot contact the owner , no replies so far.
I intend cutting a 3 x 2 inch hole in the cab top , masked with grill.
Positioning it asymmetrically off-centre in both senses so above the big
bottles and clear of internal encumberances so a 2 inch fan could be fixed
under the grill , later, if required. And the pcb perforations pf course

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
In article <gdh9qr$3vh$1@registered.motzarella.org>,
"N_Cook" <diverse@tcp.co.uk> wrote:

isw <isw@witzend.com> wrote in message
news:isw-D0858A.20485319102008@[216.168.3.50]...
In article <C2PKk.4677$yr3.2463@nlpi068.nbdc.sbc.com>,
Sofa Slug <sofaslug403spamnot@prodigy.net> wrote:

N_Cook wrote:
Ancient_Hacker <grg2@comcast.net> wrote in message

news:a52402f3-1958-45f8-8c8c-0c703532e2e9@f63g2000hsf.googlegroups.com...
You might consider adding a small DC fan. A 12V fan running off a
diode and capacitor off the (supposed) 6.3VAC heaters will be running
relatively quietly at V.




I'd half considered a fan but there is no obvious place to put it and
without cutting a hole in the steel chassis or the wood cabinet it
would
just be circulating the air, unless mounted outside the chassis ,
directed
over the bottles. Good idea about the heater supply use.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/




How about "tube coolers"? I've never used them, but if there's no room
for a fan...
http://www.partsconnexion.com/audiogon_pix/WEBPAGES/PEARL.htm

They could get the heat away from the tubes, but it'd still be in the
box. By themselves, they'd probably make little difference.

Isaac


Unfortunately I cannot contact the owner , no replies so far.
I intend cutting a 3 x 2 inch hole in the cab top , masked with grill.
Positioning it asymmetrically off-centre in both senses so above the big
bottles and clear of internal encumberances so a 2 inch fan could be fixed
under the grill , later, if required. And the pcb perforations pf course
Click to expand...
If there is not a corresponding hole in the bottom, or the bottom of the
rear panel, you should do that too. Convection can do wonders.

Isaac
 
isw <isw@witzend.com> wrote in message
news:isw-C2A5A3.21083720102008@[216.168.3.50]...
In article <gdh9qr$3vh$1@registered.motzarella.org>,
"N_Cook" <diverse@tcp.co.uk> wrote:

isw <isw@witzend.com> wrote in message
news:isw-D0858A.20485319102008@[216.168.3.50]...
In article <C2PKk.4677$yr3.2463@nlpi068.nbdc.sbc.com>,
Sofa Slug <sofaslug403spamnot@prodigy.net> wrote:
Click to expand...

If there is not a corresponding hole in the bottom, or the bottom of the
rear panel, you should do that too. Convection can do wonders.

Isaac
Click to expand...

EL34 bases are 15mm diam and the metal chassis holes 45mm so plenty of
airgap there, but absolutely no holes through the valve bases or pcb.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top