According to owner , bought it off company rep a few years ago and is export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying ac (4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up, but 3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps anywhere ?

"N_Cook" wrote in message
...
According to owner , bought it off company rep a few years ago and is
export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying ac
(4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up, but
3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps anywhere
?





What is the voltage on the heaters? If this is excessive then the whole
transformer is probably running too high.



Gareth.

Gareth Magennis wrote in message
...

"N_Cook" wrote in message
...
According to owner , bought it off company rep a few years ago and is
export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self
heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying ac
(4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up,
but
3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot
to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect
probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps
anywhere
?





What is the voltage on the heaters? If this is excessive then the whole
transformer is probably running too high.



Gareth.



I didn't think of that, all valves out for testing at the moment

No mains voltage stated at the IEC inlet, just fuses for 110 or 240V, 7
wires to the primary side of the tranformer and jumper spade matrix inside.
As the rep was going around Europe , not just the UK , I wonder if if it is
internally set to 210V.
Anyone know what the secondary voltages should be ? or how to unravel ?
power up and look for voltages 30 or 40 V off from 0,110 or 240 I suppose.
No smoothing choke for this amp it would seem, unless its in with the mains
transformer .

As the mains switch is made for 110V use then anything is possible

Meat Plow wrote in message
...
On Wed, 28 Oct 2009 10:30:08 -0000, "N_Cook" wrote:

According to owner , bought it off company rep a few years ago and is
export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying ac
(4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up, but
3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps
anywhere ?


The HT would depend on what tubes were in the output. The mains switch
illumination is derived from where?

I've seen HT from 400 to 700 volts depending on the tube and
manufacturer but if you have 450v caps your HT should be what minus 10
to 15% of the 450v caps..

What are the tube heater voltages?

Testing the valves at the moment , next time I power up I will use a variac
set for 210V or so and try and work out the 0/110/210/230 settings

"N_Cook" wrote in message
...
Gareth Magennis wrote in message
...

"N_Cook" wrote in message
...
According to owner , bought it off company rep a few years ago and is
export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self
heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying
ac
(4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up,
but
3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot
to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect
probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps
anywhere
?





What is the voltage on the heaters? If this is excessive then the whole
transformer is probably running too high.



Gareth.



I didn't think of that, all valves out for testing at the moment

No mains voltage stated at the IEC inlet, just fuses for 110 or 240V, 7
wires to the primary side of the tranformer and jumper spade matrix
inside.
As the rep was going around Europe , not just the UK , I wonder if if it
is
internally set to 210V.
Anyone know what the secondary voltages should be ? or how to unravel ?
power up and look for voltages 30 or 40 V off from 0,110 or 240 I suppose.
No smoothing choke for this amp it would seem, unless its in with the
mains
transformer .

As the mains switch is made for 110V use then anything is possible





Your best bet IMHO is trying to get the 6.3v heater winding correct via a
variac and then make a judgement.



Gareth.

"N_Cook" wrote in message
...
According to owner , bought it off company rep a few years ago and is
export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying ac
(4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up, but
3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps anywhere
?



"BV" = Blue Voodoo series. 150 similar to 60 but with more O/P valves maybe
?

http://www.schematicheaven.com/newam...voodoo_60w.pdf

This also uses 350v and 450v rated caps and max quoted HT is 460v. This is
coped with by 350v cap pairs series'd up, with v-share Rs across them.

Arfa

Arfa Daily wrote in message
...

"N_Cook" wrote in message
...
According to owner , bought it off company rep a few years ago and is
export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self
heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying ac
(4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up,
but
3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot
to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect
probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps
anywhere
?



"BV" = Blue Voodoo series. 150 similar to 60 but with more O/P valves
maybe
?

http://www.schematicheaven.com/newam...voodoo_60w.pdf

This also uses 350v and 450v rated caps and max quoted HT is 460v. This is
coped with by 350v cap pairs series'd up, with v-share Rs across them.

Arfa



I was wondering where the "B" came from and assumed V was for valve, despite
USA amp. I will download that schema and compare

I should have said previously only the 110V and 230V fuse ratings stated on
the chassis, not 2 separate fuseholders, so someone might erroneously think
it was an "intelligent" ps , no external selector switch or helpful
labelling of selector matrix inside, I'll explore that later today.

All valves test ok except one 6L6 which, apart from heater, is totally dead,
no gain at all at any anode current. There is opaque stain on the envelope
in area above pins 4 and 5, localised in that area, although it could pass
beyond the non-round, mica spacers. I assume some metal melted and
evaporated/jetted onto the glass like the getter process. I assume this
could have been plasma arc to anode and excessive current and blown mains
fuse, as that part of the amp history. What would have happened here ? I
will break into the base/glass pip/cut-ring the envelope and remove the
innards to have a good look as presently cannot see anything through the
deposit. A melted hole in the anode? what would physically stop any valve
action? the getter is still silvery.
Not yet retubed (that one plus another removed for balance) and tried out on
reduced mains yet.


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

"N_Cook" wrote in message
...
Arfa Daily wrote in message
...

"N_Cook" wrote in message
...
According to owner , bought it off company rep a few years ago and is
export
version prototype.
Blew a fuse a few weeks back , runs still ,after fuse change (self
heeled
cap?) but excessive hum.
450V rating ps electros but I measure 488V on the HT rail and varying
ac
(4
to 5 volt ac measured via 1uF, 1500V polyprop), perhaps seriesed-up,
but
3
in there, I've not taken apart yet.
The neon lit mains switch looks more like a light bulb , runs too hot
to
keep your finger on, I suspect droppers for USA mains inside. No serial
number on the chassis. Have yet to test the valves but I suspect
probably
ok, any advice on dealing with the HT/caps issue? What is the HT rail
supposed to be for USA issue ones ? Any schematic for the pa / ps
anywhere
?



"BV" = Blue Voodoo series. 150 similar to 60 but with more O/P valves
maybe
?

http://www.schematicheaven.com/newam...voodoo_60w.pdf

This also uses 350v and 450v rated caps and max quoted HT is 460v. This
is
coped with by 350v cap pairs series'd up, with v-share Rs across them.

Arfa



I was wondering where the "B" came from and assumed V was for valve,
despite
USA amp. I will download that schema and compare

I should have said previously only the 110V and 230V fuse ratings stated
on
the chassis, not 2 separate fuseholders, so someone might erroneously
think
it was an "intelligent" ps , no external selector switch or helpful
labelling of selector matrix inside, I'll explore that later today.

All valves test ok except one 6L6 which, apart from heater, is totally
dead,
no gain at all at any anode current. There is opaque stain on the envelope
in area above pins 4 and 5, localised in that area, although it could pass
beyond the non-round, mica spacers. I assume some metal melted and
evaporated/jetted onto the glass like the getter process. I assume this
could have been plasma arc to anode and excessive current and blown mains
fuse, as that part of the amp history. What would have happened here ? I
will break into the base/glass pip/cut-ring the envelope and remove the
innards to have a good look as presently cannot see anything through the
deposit. A melted hole in the anode? what would physically stop any valve
action? the getter is still silvery.
Not yet retubed (that one plus another removed for balance) and tried out
on
reduced mains yet.


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



Assuming no obvious internal o/c connections to electrodes, then a stripped
cathode is about the only thing. However, I don't quite understand your
statement "no gain at all at any anode current". It seems to me that if you
are able to see *any* anode current, then the valve is, to whatever degree,
'working', and hence has at least some gain ?? How does the tester control
the anode current ? By varying the g1 voltage ? If it does, then that would
confirm that the grid is not o/c. Thinking a bit more, you might well see
some anode current, but little 'gain' if the g2 connection was open ?

The schematic for the '60 that I pointed you at, has a detailed diagram set
of the primary connection arrangement for different voltages. Probably a
similar scheme to the '150 ?

Arfa

Arfa Daily wrote in message
...

"N_Cook" wrote in message
...
Arfa Daily wrote in message
...

"N_Cook" wrote in message
...


Assuming no obvious internal o/c connections to electrodes, then a
stripped
cathode is about the only thing. However, I don't quite understand your
statement "no gain at all at any anode current". It seems to me that if
you
are able to see *any* anode current, then the valve is, to whatever
degree,
'working', and hence has at least some gain ?? How does the tester control
the anode current ? By varying the g1 voltage ? If it does, then that
would
confirm that the grid is not o/c. Thinking a bit more, you might well see
some anode current, but little 'gain' if the g2 connection was open ?

The schematic for the '60 that I pointed you at, has a detailed diagram
set
of the primary connection arrangement for different voltages. Probably a
similar scheme to the '150 ?

Arfa



Other than heater continuity it tests as though no valve placed in the
socket.

Same colour code of primary, not secondaries , as that blue voodo and
seemingly the same significances. But I'll have to take apart to check what
is jumpered to what, and also the HT1 smoothing is different as it uses 3 ,
not 4 caps there. I forgot to check each voltage on the 7 primary wires,
will do so next.

With the duff 6L6 and one other removed
Putting 199V on the existing setting of primaries gives 5.65V ac so
suggesting 6.53V ac if 230V fed in on existing internal set primaries. Is
6V ac on that Crate BV60 schematic a strict ie +/- 0.1V, or nominal 6V (with
all 14 heaters supplied presumably)
Also 199v "mains" gives 407V HT1

The hum is present but with my variac I can lift the ground and doing that,
the hum goes and amp works fine , normally testing an amp there is no hum
and lifting the ground can introduce hum , so I wonder what other problem
lurks. 1000V megga test on the mains Tx shows nothing amiss to ground.


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

Looks like the same colours but not necessarily the same taps.

Monitored the total primary resistance and marked, removed/replaced spade
connections until 3 spade connectors blue , grey and black removed without
affecting reading . Leaving blue+white stripe, white,brown and violet as the
primary.

Powering up on 199V wrt to neutral the free wires read
blue 190.3
grey 86.4
black 206

wrt live
blue 8.3
grey 120
black 8.8V

is this the setting for 210V, 230V or 240V ?, I'm trying to get the maximum
number of turns as the primary. I'm thinking I need to swap the blue+white
with the black lead. If complete agreement with that Blue Voodoo 60 then the
existing wiring is undefined on that chart, the J numbering does not tally
with this one

Broke into the 6L6 , I thought the caesium getter went white immediately but
takes a few minutes, envelope safely sealed separately now.
The outer grey metalwork anode had a bright metal spot adjascent to where
the black envelope staining was. Cutting half the anode away revealed a bare
metal patch on the otherwise white coating of the cathode, no pools of metal
or smoke trails, G1 winding looked fine. I'm surprised how tough the
mica/composite ? spacers are compared to similar I've seen inside toasters


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

Exploring the 6L6 a bit more there was continuity between the base pin and
G3 but the internal contact to the cathode was missing. Presumably a
deliberate weak fusible link in whatever occassions a plasma arc strikes
between cathode and anode.

Looks as though the hum was associated with the input socket. This is
designed to be isolated from chassis taking ground from screened lead. As it
was turning round with tight bush nut I assume someone had been in there and
changed the insulating bushes about so ground-looped, now isolated and tight
and no undue hum.

Looked under the pa board and it is 2 seriesed 47uF,450V for HT1 and the
other one with a dropper for another HT.
date 2003 or later.
Mains primary now set for presumably 250V as heater readings are still a bit
high.
So with full mains on there and all 8 12AX7 and only 4 of the 6 off 6L6
reads quiescent 6.6V ac and 470V HT1 from 356V ac, other secondaries or/or
32.8V ac and bu/bu 66V ac.
Incidently not only the neon /sw needed attention but the handle is crap
and jagged sharp metal exposed inside, covered with nylon spiral wrap, then
expanding nylon sleeving and then 2 layers heatshrink all under the covering
now


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

I cut the pins at the base of the 6L6 envelope to see that area and the
ribbon that connects to the cathode tube is spark eroded to a ragged break.
This ribbon is 0.5 x 0.04mm in section, if it was copper then I make the
rupture current would be about 6 amps. Presumably failed at a weld spot so
less than that

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