Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old September 22nd 10, 04:23 PM posted to sci.electronics.repair
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Default Fender Showman from 1963

Known history with this , from its purchase in Germany onwards, including
its original set of valves (not in there and used now, but will test out of
curiosity). What are the main potential safety/reliability issues with an
amp of this age? All the cotton covered wiring looks good but is there some
test/procedure more convincing as to insualting value? Bakelite brittleness
in the valve bases? metallurgical failure of springiness of valve
contacts?
Someone modified to 3 core mains cable and made an earth point, for 240V
land, at some point in its history. Numerous caps replaced in 1991 and 1997
and some carbon R replaced with MO at some point. I've not checked the main
caps yet.



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Old September 22nd 10, 05:17 PM posted to sci.electronics.repair
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Default Fender Showman from 1963

On Wed, 22 Sep 2010 15:23:05 +0100, N_Cook wrote:

Known history with this , from its purchase in Germany onwards,
including its original set of valves (not in there and used now, but
will test out of curiosity). What are the main potential
safety/reliability issues with an amp of this age? All the cotton
covered wiring looks good but is there some test/procedure more
convincing as to insualting value? Bakelite brittleness in the valve
bases? metallurgical failure of springiness of valve contacts?
Someone modified to 3 core mains cable and made an earth point, for 240V
land, at some point in its history. Numerous caps replaced in 1991 and
1997 and some carbon R replaced with MO at some point. I've not checked
the main caps yet.


No known safety issues other than mains wiring. These were pretty
reliable amps. I own a 1970 Showman USA model. Someone tried to turn it
into a 100 watt model by replacing the iron and adding two octals to the
already blanked out chassis. I ripped all that stuff out and put new
output iron in it. It's not worth much but it does sound sweet.



--
Live Fast, Die Young and Leave a Pretty Corpse
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Old September 22nd 10, 06:39 PM posted to sci.electronics.repair
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Default Fender Showman from 1963

Meat Plow wrote in message
news
On Wed, 22 Sep 2010 15:23:05 +0100, N_Cook wrote:

Known history with this , from its purchase in Germany onwards,
including its original set of valves (not in there and used now, but
will test out of curiosity). What are the main potential
safety/reliability issues with an amp of this age? All the cotton
covered wiring looks good but is there some test/procedure more
convincing as to insualting value? Bakelite brittleness in the valve
bases? metallurgical failure of springiness of valve contacts?
Someone modified to 3 core mains cable and made an earth point, for 240V
land, at some point in its history. Numerous caps replaced in 1991 and
1997 and some carbon R replaced with MO at some point. I've not checked
the main caps yet.


No known safety issues other than mains wiring. These were pretty
reliable amps. I own a 1970 Showman USA model. Someone tried to turn it
into a 100 watt model by replacing the iron and adding two octals to the
already blanked out chassis. I ripped all that stuff out and put new
output iron in it. It's not worth much but it does sound sweet.



--
Live Fast, Die Young and Leave a Pretty Corpse




Closer look and the cotton covering to the wiring between the output heaters
is "perished", crumbling to dust, and needs replacing. Strange having a load
of Mullard, Brimar and Z&I Aero valves to test


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Old September 22nd 10, 06:47 PM posted to sci.electronics.repair
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Default Fender Showman from 1963

On Wed, 22 Sep 2010 17:39:27 +0100, N_Cook wrote:

Meat Plow wrote in message
news
On Wed, 22 Sep 2010 15:23:05 +0100, N_Cook wrote:

Known history with this , from its purchase in Germany onwards,
including its original set of valves (not in there and used now, but
will test out of curiosity). What are the main potential
safety/reliability issues with an amp of this age? All the cotton
covered wiring looks good but is there some test/procedure more
convincing as to insualting value? Bakelite brittleness in the valve
bases? metallurgical failure of springiness of valve contacts?
Someone modified to 3 core mains cable and made an earth point, for
240V land, at some point in its history. Numerous caps replaced in
1991 and 1997 and some carbon R replaced with MO at some point. I've
not checked the main caps yet.


No known safety issues other than mains wiring. These were pretty
reliable amps. I own a 1970 Showman USA model. Someone tried to turn it
into a 100 watt model by replacing the iron and adding two octals to
the already blanked out chassis. I ripped all that stuff out and put
new output iron in it. It's not worth much but it does sound sweet.



--
Live Fast, Die Young and Leave a Pretty Corpse




Closer look and the cotton covering to the wiring between the output
heaters is "perished", crumbling to dust, and needs replacing. Strange
having a load of Mullard, Brimar and Z&I Aero valves to test


Since the heater wiring is twisted it would be a good idea to replace if
it is that poor of a state. I don't recall ever seeing the LV wiring in
any Fender of that era in that state and the state of all the wiring is
what I usually inspect first on any P2P wired vintage amp.




--
Live Fast, Die Young and Leave a Pretty Corpse
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Old September 22nd 10, 08:17 PM posted to sci.electronics.repair
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Default Fender Showman from 1963

On 22/09/2010 17:39, N_Cook wrote:

Closer look and the cotton covering to the wiring between the output heaters
is "perished", crumbling to dust, and needs replacing. Strange having a load
of Mullard, Brimar and Z&I Aero valves to test


Z&I Aero!!! I haven't heard that name for over 40 years. That was when
their shop in Tottenham Court Road was worth visiting, followed by a
stroll to Proops, and then onto Lisle Street. Are there any surplus
places worth visiting today?

--

Jeff


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Old September 23rd 10, 03:18 AM posted to sci.electronics.repair
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Default Fender Showman from 1963



"Jeff Layman" wrote in message
...
On 22/09/2010 17:39, N_Cook wrote:

Closer look and the cotton covering to the wiring between the output
heaters
is "perished", crumbling to dust, and needs replacing. Strange having a
load
of Mullard, Brimar and Z&I Aero valves to test


Z&I Aero!!! I haven't heard that name for over 40 years. That was when
their shop in Tottenham Court Road was worth visiting, followed by a
stroll to Proops, and then onto Lisle Street. Are there any surplus
places worth visiting today?

--

Jeff


I still have a Z&I Aero (Zaerix) glossy covered catalogue / data book in
near pristine condition. It has data on lovely old things like VCR97 'scope
tubes, and has all the prices in pounds, shillings and pence ! Oh those
lovely old days of skiving off school for the day and jumping on the train
to London to go to Tottenham Court Road and Lisle Street. Into Henry's Radio
.... I bought my first 'hifi' amplifier in Proops. It's a Teleton SAQ-307.
It's here in the computer room with me, and I'm looking at it right now.
Still works as good as the day it was bought. Only about 8 watts per channel
as I recall, but punched way above that weight. It drives my EMI 13 x 8 cabs
with 7 x 5 mids and Eagle dome tweeters. The EMIs came from Henry's and the
Eagles from Maplin I think, but might have been Tandy (Radio Shack). I also
have the matching Teleton GT-203 tuner, and then the Nikko ND-790 cassette
deck. Remember those ? All together, it was the classic "poor man's" hifi
rig of the early 70s.

I think most of the wonderful old junk shops have pretty much gone now, but
I think that Anchor Supplies up in Nottingham is still going. Remember AH
Supplies ? They used to advertise every month in Practically Witless
magazine, and I bought a lot of ex WW2 radios like 19 sets and an R1392 and
a Wavemeter D from them. I have a feeling that they might still be going in
one form or another. I'm also pretty sure that Birketts over in Lincoln
somewhere are still going too. Then there was John's Radio, and Bull
Electrical. Happy days ... Blimey. I've just looked up John's Radio, and
they are still going !

Arfa

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Old September 23rd 10, 03:29 AM posted to sci.electronics.repair
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Default Fender Showman from 1963

On Sep 22, 2:17*pm, Jeff Layman wrote:
On 22/09/2010 17:39, N_Cook wrote:

Closer look and the cotton covering to the wiring between the output heaters
is "perished", crumbling to dust, and needs replacing. Strange having a load
of Mullard, Brimar and Z&I Aero valves to test


Z&I Aero!!! *I haven't heard that name for over 40 years. *That was when
their shop in Tottenham Court Road was worth visiting, followed by a
stroll to Proops, and then onto Lisle Street. *Are there any surplus
places worth visiting today?

--

Jeff


Tottenham Court Road... Proops... Lisle Street...
Brings back memories!
Cheers,
Roger
(in Canada since 1970...)
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Old September 23rd 10, 09:22 AM posted to sci.electronics.repair
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Posts: 5,225
Default Fender Showman from 1963

Meat Plow wrote in message
news
On Wed, 22 Sep 2010 17:39:27 +0100, N_Cook wrote:

Meat Plow wrote in message
news
On Wed, 22 Sep 2010 15:23:05 +0100, N_Cook wrote:

Known history with this , from its purchase in Germany onwards,
including its original set of valves (not in there and used now, but
will test out of curiosity). What are the main potential
safety/reliability issues with an amp of this age? All the cotton
covered wiring looks good but is there some test/procedure more
convincing as to insualting value? Bakelite brittleness in the valve
bases? metallurgical failure of springiness of valve contacts?
Someone modified to 3 core mains cable and made an earth point, for
240V land, at some point in its history. Numerous caps replaced in
1991 and 1997 and some carbon R replaced with MO at some point. I've
not checked the main caps yet.

No known safety issues other than mains wiring. These were pretty
reliable amps. I own a 1970 Showman USA model. Someone tried to turn it
into a 100 watt model by replacing the iron and adding two octals to
the already blanked out chassis. I ripped all that stuff out and put
new output iron in it. It's not worth much but it does sound sweet.



--
Live Fast, Die Young and Leave a Pretty Corpse




Closer look and the cotton covering to the wiring between the output
heaters is "perished", crumbling to dust, and needs replacing. Strange
having a load of Mullard, Brimar and Z&I Aero valves to test


Since the heater wiring is twisted it would be a good idea to replace if
it is that poor of a state. I don't recall ever seeing the LV wiring in
any Fender of that era in that state and the state of all the wiring is
what I usually inspect first on any P2P wired vintage amp.




--
Live Fast, Die Young and Leave a Pretty Corpse



The conductor size, under the insulation, is only 0.7mm presumably not
enough for the current plus localised heating. Will replace with silicon
sleeved wire with "Refrasil" glass sleeving over that , dulled down with
dark green permanent ink felt tip pen, gives a very convincing contemporary
look, and surprisingly does not wipe off the glass


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Old September 23rd 10, 11:53 AM posted to sci.electronics.repair
Ron Ron is offline
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Posts: 314
Default Fender Showman from 1963

On 23/09/2010 02:18, Arfa Daily wrote:


"Jeff Layman" wrote in message
...
On 22/09/2010 17:39, N_Cook wrote:

Closer look and the cotton covering to the wiring between the output
heaters
is "perished", crumbling to dust, and needs replacing. Strange having
a load
of Mullard, Brimar and Z&I Aero valves to test


Z&I Aero!!! I haven't heard that name for over 40 years. That was when
their shop in Tottenham Court Road was worth visiting, followed by a
stroll to Proops, and then onto Lisle Street. Are there any surplus
places worth visiting today?

--

Jeff


I still have a Z&I Aero (Zaerix) glossy covered catalogue / data book in
near pristine condition. It has data on lovely old things like VCR97
'scope tubes, and has all the prices in pounds, shillings and pence ! Oh
those lovely old days of skiving off school for the day and jumping on
the train to London to go to Tottenham Court Road and Lisle Street. Into
Henry's Radio ... I bought my first 'hifi' amplifier in Proops. It's a
Teleton SAQ-307. It's here in the computer room with me, and I'm looking
at it right now. Still works as good as the day it was bought. Only
about 8 watts per channel as I recall, but punched way above that
weight. It drives my EMI 13 x 8 cabs with 7 x 5 mids and Eagle dome
tweeters. The EMIs came from Henry's and the Eagles from Maplin I think,
but might have been Tandy (Radio Shack). I also have the matching
Teleton GT-203 tuner, and then the Nikko ND-790 cassette deck. Remember
those ? All together, it was the classic "poor man's" hifi rig of the
early 70s.

I think most of the wonderful old junk shops have pretty much gone now,
but I think that Anchor Supplies up in Nottingham is still going.
Remember AH Supplies ? They used to advertise every month in Practically
Witless magazine, and I bought a lot of ex WW2 radios like 19 sets and
an R1392 and a Wavemeter D from them. I have a feeling that they might
still be going in one form or another. I'm also pretty sure that
Birketts over in Lincoln somewhere are still going too. Then there was
John's Radio, and Bull Electrical. Happy days ... Blimey. I've just
looked up John's Radio, and they are still going !

Arfa


Teleton SAQ-307! yes I had one o them. Marvelous amplifier, didn't it
have some unusual feature for it's day, slider control or something?
I had mine in my shop driving a stack consiting of a 15" Gauss in a
home made Altec Voice of the Theatre copy, a 12" Gauss VotT copy and a
whopping great Vitavox multicell horn (courtesy of the recently closed
local ODEON). No electronic crossovers in those days!
Even tho it was only a few watts, it could visibly make the shop window
shake in time to the music (Dark Side of the Moon - Most impressive)

Ron(UK)

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SPAMfighter has removed 2512 of my spam emails to date.
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Old September 23rd 10, 01:31 PM posted to sci.electronics.repair
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Posts: 5,225
Default Fender Showman from 1963

At least not best wiring practise, wires not looped thru tags (2 passes)
before soldering. Although original wiring , a 6L6 socket has been replaced
at some time. Did he swap around the wires and so the heater pinning is
different? . The original "push" pair have opposite polarity pinning for the
heaters of each but the "pull" pair, with the replaced socket, are same
"polarity". I'm inclined to replace the wiring with both pairs having
alternate polarity




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