Rega RB300 turntable...
 

Hi all

Anyone happen to know the value of the resistor in the CR network connected
in the synchronous motor feed ? Looks like brown - red - brown so 120 ohms,
but it's well overheated and discoloured, with a nice burn mark right around
the spiral element, right in the centre. Can't get a reading from either end
to the burn point. Looks at a guess to be rated about 3 -5 watts. Anybody
think of a reason *not* to use a wirewound rather than the original metal
film type ?

Arfa

Rega RB300 turntable...
 

Arfa Daily wrote in message
...
Hi all

Anyone happen to know the value of the resistor in the CR network
connected
in the synchronous motor feed ? Looks like brown - red - brown so 120
ohms,
but it's well overheated and discoloured, with a nice burn mark right
around
the spiral element, right in the centre. Can't get a reading from either
end
to the burn point. Looks at a guess to be rated about 3 -5 watts. Anybody
think of a reason *not* to use a wirewound rather than the original metal
film type ?

Arfa



Wasn't Rega tonearms only?
What sort of vintage is the deck? Is it definitely for use on 240V mains ?


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://diverse.4mg.com/index.htm

Rega RB300 turntable...
 

In article ,
Arfa Daily wrote:
Hi all

Anyone happen to know the value of the resistor in the CR network
connected in the synchronous motor feed ? Looks like brown - red -
brown so 120 ohms, but it's well overheated and discoloured, with a
nice burn mark right around the spiral element, right in the centre.
Can't get a reading from either end to the burn point. Looks at a guess
to be rated about 3 -5 watts. Anybody think of a reason *not* to use a
wirewound rather than the original metal film type ?

Only thing I can think of is a metal film one will be more stable?

--
*Errors have been made. Others will be blamed.

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

Rega RB300 turntable...
 

"N_Cook" writes:

Wasn't Rega tonearms only?

No, but the RB300 is indeed a tonearm, rather than a turntable. There
are PDF manuals on vinylengine.com for a bunch of Rega tonearms and
turntables which might help identify what the deck actually is.

It's worth noting that the discussion on the page for the Planar 3
(which would be a plausible turntable to have an RB300 fitted) has some
comments on replacement motor resistor values, with one comment
suggesting 150 ohm 5%:
http://www.vinylengine.com/library/rega/planar-3.shtml

--
Adam Sampson http://offog.org/

Rega RB300 turntable...
 

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

Anyone happen to know the value of the resistor in the CR network
connected
in the synchronous motor feed ? Looks like brown - red - brown so 120
ohms,
but it's well overheated and discoloured, with a nice burn mark right
around
the spiral element, right in the centre. Can't get a reading from either
end
to the burn point. Looks at a guess to be rated about 3 -5 watts. Anybody
think of a reason *not* to use a wirewound rather than the original metal
film type ?

Arfa



Wasn't Rega tonearms only?
What sort of vintage is the deck? Is it definitely for use on 240V mains ?


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://diverse.4mg.com/index.htm


Well, sort of. I guess that the full deck is probably a Rega Planar 3, but
definitely a Rega-original product. There is a "Grahams HiFi London" tested
sticker on the bottom with a handwritten date of '86 on it. There is a
manufacturer's label on the bottom also saying "rega Made in Britain" and
"Rega Research Ltd"

To the best of my knowledge, it has always been used here in the UK.The
motor is a synchronous type, 4 wire, and marked 110v 50Hz. Two grey wires go
straight to mains neutral. Switched mains live comes back to a small
(original looking) PCB in the motor compartment. It passes through the R in
question to to the motor red wire. There is then a cap, 0.22u 400v
polyester, between the red wire and the blue wire, so I guess that this RC
combination is a phase shift / AC dropper so that the motor is happy at
240v. There is no indication on any of the labels as to the voltage specs,
but the fact that it is a 50Hz synchronous motor single speed deck, and also
that the mains lead is absolutely original and coloured blue and brown,
would suggest that this was built for use in europe on 50Hz mains of at
least 220v ??

Arfa

Rega RB300 turntable...
 

On Mon, 17 May 2010 09:57:09 +0100, Arfa Daily wrote:

Hi all

Anyone happen to know the value of the resistor in the CR network
connected in the synchronous motor feed ? Looks like brown - red - brown
so 120 ohms, but it's well overheated and discoloured, with a nice burn
mark right around the spiral element, right in the centre. Can't get a
reading from either end to the burn point. Looks at a guess to be rated
about 3 -5 watts. Anybody think of a reason *not* to use a wirewound
rather than the original metal film type ?

Arfa

Did you try a 120 and see what happens (with some current limiting in
place) With things like this I usually clip in a light fuse in case the
resistor was actually 1200 ohms or more :)

Rega RB300 turntable...
 

"Adam Sampson" wrote in message
...
"N_Cook" writes:

Wasn't Rega tonearms only?

No, but the RB300 is indeed a tonearm, rather than a turntable. There
are PDF manuals on vinylengine.com for a bunch of Rega tonearms and
turntables which might help identify what the deck actually is.

It's worth noting that the discussion on the page for the Planar 3
(which would be a plausible turntable to have an RB300 fitted) has some
comments on replacement motor resistor values, with one comment
suggesting 150 ohm 5%:
http://www.vinylengine.com/library/rega/planar-3.shtml

--
Adam Sampson http://offog.org/

Thanks Adam. It is indeed a Planar 3. I had in fact already been on that
site, and seen the reference to the 150 ohm resistor. I suppose it's
possible that there might be more than one value having been fitted over the
life of production, because given 40 odd years of looking at burnt and
discoloured resistor stripes, I definitely would not have said that the
middle one was originally green, but who knows ? (well, hopefully someone on
one of these groups does ! ) I was pretty sure that the first two were
brown and red for 1- 2 - something. I was just concerned that if the final
band was red, or even orange, I didn't want to be putting 120 ohms in there
....

Arfa

Rega RB300 turntable...
 

"Meat Plow" wrote in message
...
On Mon, 17 May 2010 09:57:09 +0100, Arfa Daily wrote:

Hi all

Anyone happen to know the value of the resistor in the CR network
connected in the synchronous motor feed ? Looks like brown - red - brown
so 120 ohms, but it's well overheated and discoloured, with a nice burn
mark right around the spiral element, right in the centre. Can't get a
reading from either end to the burn point. Looks at a guess to be rated
about 3 -5 watts. Anybody think of a reason *not* to use a wirewound
rather than the original metal film type ?

Arfa

Did you try a 120 and see what happens (with some current limiting in
place) With things like this I usually clip in a light fuse in case the
resistor was actually 1200 ohms or more :)

If no closer to a definitive answer by tomorrow, Meat, I'll probably go down
that route.

Arfa

Rega RB300 turntable...
 

Arfa Daily wrote:
Hi all

Anyone happen to know the value of the resistor in the CR network connected
in the synchronous motor feed ? Looks like brown - red - brown so 120 ohms,
but it's well overheated and discoloured, with a nice burn mark right around
the spiral element, right in the centre. Can't get a reading from either end
to the burn point. Looks at a guess to be rated about 3 -5 watts. Anybody
think of a reason *not* to use a wirewound rather than the original metal
film type ?

Arfa


Hi Arfa
Just took the cover off a Rega Planar 3 and the board has 5 components
on it.
1 x .22uf 275v ac cap (220nf)
1 x 10k 5% 1-2 watt parallel (physically) to the cap (bn bk or -gold)
1 x 1M 1% 1/4 watt (br bk bk yell -bn)
1 x 3k3 1% 1/4 watt (or or bk bn -bn)
1 x 120nf 400v dc cap
HTH
DaveD

Rega RB300 turntable...
 

"DaveD" wrote in message
...
Arfa Daily wrote:
Hi all

Anyone happen to know the value of the resistor in the CR network
connected in the synchronous motor feed ? Looks like brown - red - brown
so 120 ohms, but it's well overheated and discoloured, with a nice burn
mark right around the spiral element, right in the centre. Can't get a
reading from either end to the burn point. Looks at a guess to be rated
about 3 -5 watts. Anybody think of a reason *not* to use a wirewound
rather than the original metal film type ?

Arfa
Hi Arfa
Just took the cover off a Rega Planar 3 and the board has 5 components on
it.
1 x .22uf 275v ac cap (220nf)
1 x 10k 5% 1-2 watt parallel (physically) to the cap (bn bk or -gold)
1 x 1M 1% 1/4 watt (br bk bk yell -bn)
1 x 3k3 1% 1/4 watt (or or bk bn -bn)
1 x 120nf 400v dc cap
HTH
DaveD

Hmmm. Well Dave, I've got to say that that bears no relationship to what's
in this one, at all :-\

It definitely says "Rega Planar 3" at the top front right corner, although
it's hard to see as the letters are just black 'shininess' within the black
satin anodised finish of the cabinet. Underneath, directly under the motor,
is a cover secured by two screws, When this is removed, the motor and a
small PCB are revealed. The PCB has just two components on it - the burnt up
R, which is a large 'film' type, I guess something like about 5mm diameter
and 20mm or so long, and the 0.22u 400v cap, which is one of those green MKT
monobloc types. These two components are mounted 'on the slant' on the
board. The mains comes in, and the neutral is joined immediately to two grey
wires from the motor. The live leaves the board again on a white wire which
goes to the on / off switch at the front top left of the deck. Live returns
to the board on another white, and goes to the motor red lead via the burnt
up resistor. The cap is between the red lead and the remaining blue lead.
Doesn't sound much like the example that you're looking at, eh ?

Mind you, dunno about you, but I find this all the time with 'high-end'
gear. Guts that are nothing like what the the service manuals say they
should be, poorly done mods involving extra components stuck across boards,
bog-standard cheap as chips lasers fitted to CD players costing thousands,
metalwork that fits where it touches, holes drilled in wrong places,
inappropriate screw types and sizes - the list is endless.

I know that these things are often hand-built, which I guess is what
attracts the people with more money than sense to them, but when I look at
some items, I wonder how the companies that made them, and then stuck the
multi-thousand pound price tags on them, sleep at night. I guess I've just
got too much of a conscience ...

Anyways, I think tomorrow that I am going to fit a 5 watt 150 ohm wirewound
that I have to hand, and then bring it up gently on the variac, and see what
happens. I guess it's got two chances ... :-)

Arfa