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From: Arfa Daily on 28 Oct 2009 21:31

"N_Cook" <diverse(a)tcp.co.uk> wrote in message
news:hc96gi$2gh$1(a)news.eternal-september.org...
> 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/newamps/crate_bluevoodoo_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


From: N_Cook on 29 Oct 2009 04:18
Arfa Daily <arfa.daily(a)ntlworld.com> wrote in message
news:Nf6Gm.44550$kl7.4978(a)newsfe05.ams2...
>
> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
> news:hc96gi$2gh$1(a)news.eternal-september.org...
> > 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/newamps/crate_bluevoodoo_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/



From: Arfa Daily on 29 Oct 2009 07:40

"N_Cook" <diverse(a)tcp.co.uk> wrote in message
news:hcbj55$qh9$1(a)news.eternal-september.org...
> Arfa Daily <arfa.daily(a)ntlworld.com> wrote in message
> news:Nf6Gm.44550$kl7.4978(a)newsfe05.ams2...
>>
>> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
>> news:hc96gi$2gh$1(a)news.eternal-september.org...
>> > 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/newamps/crate_bluevoodoo_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


From: N_Cook on 29 Oct 2009 08:03
Arfa Daily <arfa.daily(a)ntlworld.com> wrote in message
news:7bfGm.16603$7Y2.6097(a)newsfe27.ams2...
>
> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
> news:hcbj55$qh9$1(a)news.eternal-september.org...
> > Arfa Daily <arfa.daily(a)ntlworld.com> wrote in message
> > news:Nf6Gm.44550$kl7.4978(a)newsfe05.ams2...
> >>
> >> "N_Cook" <diverse(a)tcp.co.uk> wrote in message
> >> news:hc96gi$2gh$1(a)news.eternal-september.org...

>
> 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/



From: N_Cook on 29 Oct 2009 11:10
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/



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