Incredably neavy lump. Unused for years and unknown history and mains lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly clean and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse

"N Cook" wrote in message
...
Incredably neavy lump. Unused for years and unknown history and mains lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly clean
and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse





looks like the unlabelled touch strip on the front powered by the small
transformer hidden under the relay.
I wonder what
mains voltage is required before the touch action works and the relay clicks
over

The 120V version of the 730 has a primary power switch on the back, but the 120/240V version
does not. Not sure about the 220V version. The main power switch is the touch-sensor button
on the front, which is powered by a small transformer/supply that's always on(unless the rear
switch is off, on the 120v version at least). For this reason, it is not possible to bring it
up on a variac, but I would not even consider that necessary. Other than occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner), their pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA) in the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message
...
Incredably neavy lump. Unused for years and unknown history and mains lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly clean and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse

"Stephen Sank" wrote in message
...
The 120V version of the 730 has a primary power switch on the back, but
the 120/240V version
does not. Not sure about the 220V version. The main power switch is the
touch-sensor button
on the front, which is powered by a small transformer/supply that's always
on(unless the rear
switch is off, on the 120v version at least). For this reason, it is not
possible to bring it
up on a variac, but I would not even consider that necessary. Other than
occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner), their
pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA) in
the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message
...
Incredably neavy lump. Unused for years and unknown history and mains
lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly clean
and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse







I've fully powered up now
Yes at least 6 bulbs blown
Problem with no powered control of volume although it did fire up randomly
when I wasn't looking.
Also maybe no radio o/p as manually changing volume setting plenty
of audio o/p on aux under volume control but no radio throughput.
on FM function select
The tuner motor system works fine up/down or presets
I assume the 6V battery keeps the 4066s happy with I/P and function
and tuner selects stored.

Volume motor problem was due to a broken trace at the solder point
of pin 1 of CN-19 the orange bunch of wires to the Tuner pcb,
now the radio prob

"N Cook" wrote in message
...

"Stephen Sank" wrote in message
...
The 120V version of the 730 has a primary power switch on the back, but
the 120/240V version
does not. Not sure about the 220V version. The main power switch is
the
touch-sensor button
on the front, which is powered by a small transformer/supply that's
always
on(unless the rear
switch is off, on the 120v version at least). For this reason, it is
not
possible to bring it
up on a variac, but I would not even consider that necessary. Other
than
occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner),
their
pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA)
in
the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message
...
Incredably neavy lump. Unused for years and unknown history and mains
lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly
clean
and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse







I've fully powered up now
Yes at least 6 bulbs blown
Problem with no powered control of volume although it did fire up randomly
when I wasn't looking.
Also maybe no radio o/p as manually changing volume setting plenty
of audio o/p on aux under volume control but no radio throughput.
on FM function select
The tuner motor system works fine up/down or presets
I assume the 6V battery keeps the 4066s happy with I/P and function
and tuner selects stored.

"N Cook" wrote in message
...
Volume motor problem was due to a broken trace at the solder point
of pin 1 of CN-19 the orange bunch of wires to the Tuner pcb,
now the radio prob

"N Cook" wrote in message
...

"Stephen Sank" wrote in message
...
The 120V version of the 730 has a primary power switch on the back,
but
the 120/240V version
does not. Not sure about the 220V version. The main power switch is
the
touch-sensor button
on the front, which is powered by a small transformer/supply that's
always
on(unless the rear
switch is off, on the 120v version at least). For this reason, it is
not
possible to bring it
up on a variac, but I would not even consider that necessary. Other
than
occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner),
their
pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA)
in
the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message
...
Incredably neavy lump. Unused for years and unknown history and
mains
lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly
clean
and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse







I've fully powered up now
Yes at least 6 bulbs blown
Problem with no powered control of volume although it did fire up
randomly
when I wasn't looking.
Also maybe no radio o/p as manually changing volume setting plenty
of audio o/p on aux under volume control but no radio throughput.
on FM function select
The tuner motor system works fine up/down or presets
I assume the 6V battery keeps the 4066s happy with I/P and function
and tuner selects stored.





Radio ok - wrong combination of unlit buttons plus
as no Dolby logo ICs I assume the missing plug in of 10 way CN-1
is for Dolby but is missing. With that set on front there is no radio
throughput.
Stereo separation is week - anyone know how to adjust
the IF coil presumably buried in large screened can LF301 ?

Hello there,

Since you seem to know a lot about Nakamichi stuff, maybe you can help
me a bit on my OMS 7ii issue ? =)

Most of the times player simply doesn't want to read 'TOC' ... but
once it acknowledge one CD, it will play fine, even continuously with
repeat. Track to track search is quite fast, implying laser is still
doing a good job. Eject the disc and put it back on, cdp refused to
play again. Just like a heavy case of alzheimer.

I'd really appreciate if you can help me pinpoint the source of
problem.

Thank you very much for your time !

Best regards,
Salim SM


"Stephen Sank" wrote in message ...
The 120V version of the 730 has a primary power switch on the back, but the 120/240V version
does not. Not sure about the 220V version. The main power switch is the touch-sensor button
on the front, which is powered by a small transformer/supply that's always on(unless the rear
switch is off, on the 120v version at least). For this reason, it is not possible to bring it
up on a variac, but I would not even consider that necessary. Other than occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner), their pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA) in the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message

If the player gives up instantly, as if there was no disc in the tray, it's simply a faulty
optosensor(under right front of tray). If it spins up the disc & then gives up(which would
normally cause the player to auto eject), it may be that the laser output is just on the
borderline between ok & not ok. For this, you need a laser power meter, and it should output
0.24mW. You need to block the optosensor(just a piece of masking or electrical tape over the
hole at right front of tray), then power up the player to get the laser to run with no disc.
The trimpot on the laser itself is the power adjust.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"salim sm" wrote in message
om...
Hello there,

Since you seem to know a lot about Nakamichi stuff, maybe you can help
me a bit on my OMS 7ii issue ? =)

Most of the times player simply doesn't want to read 'TOC' ... but
once it acknowledge one CD, it will play fine, even continuously with
repeat. Track to track search is quite fast, implying laser is still
doing a good job. Eject the disc and put it back on, cdp refused to
play again. Just like a heavy case of alzheimer.

I'd really appreciate if you can help me pinpoint the source of
problem.

Thank you very much for your time !

Best regards,
Salim SM


"Stephen Sank" wrote in message ...
The 120V version of the 730 has a primary power switch on the back, but the 120/240V
version
does not. Not sure about the 220V version. The main power switch is the touch-sensor
button
on the front, which is powered by a small transformer/supply that's always on(unless the
rear
switch is off, on the 120v version at least). For this reason, it is not possible to bring
it
up on a variac, but I would not even consider that necessary. Other than occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner), their pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA) in the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message

Thank you very much sir!! Disk spin and I'll tweak the trimpot a bit soon.

Btw how did you like the music from Enigma ?

Talk to you again soon (hopefully =)
Salim SM


"Stephen Sank" wrote in message ...
If the player gives up instantly, as if there was no disc in the tray, it's simply a faulty
optosensor(under right front of tray). If it spins up the disc & then gives up(which would
normally cause the player to auto eject), it may be that the laser output is just on the
borderline between ok & not ok. For this, you need a laser power meter, and it should output
0.24mW. You need to block the optosensor(just a piece of masking or electrical tape over the
hole at right front of tray), then power up the player to get the laser to run with no disc.
The trimpot on the laser itself is the power adjust.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com

Radio ok - wrong combination of unlit buttons plus
as no Dolby logo ICs I assume the missing plug in of 10 way CN-1
is for Dolby but is missing. With that set on front there is no radio
throughput.
Stereo separation is week - anyone know how to adjust
the IF coil presumably buried in large screened can LF301 ?



Success eventually.
I seem to have accidently found a technique for stereo
problems on this receiver.
Disconnect pin 1 (5 ? not marked ) from housing in the violet CN-7 connector
that connects to upc1161 pin 9.
I looked at the DC voltages on the uPC1161, supply pin is
pin 1 at 11V but the pin 9 which connects to CN-7 was 12V
and 12V coming from front panel , so thinking a fault on front
pannel. When disconnected taking
this lead via 100R to ground then the stereo light comes on dim.
Anyway with this line disconnected the pin 9 signal jumps to
a 5V or so pk-pk PLL signal but rough triangular form and 2.2V dc
Now locked into 19.000 KHz over a good 20% of VR302
and plenty of signal for a f counter to confirm.

With a screwdriver to inject hum at the ends of VR303 hum
is either in L or R channel but without stereo lamp to
indicate, touch front contact and hum is central.

The tuning slug buried in the Nakamichi IF block under cable bunch
needed adjusting slightly to bring up quadrature ? and the stereo decoding
and then
pin 9 dropping to .4V dc and 0.2V pk-pk square wave at PLL
19 KHz. Then reconnecting the CN-7 line these pin 9 ac signals
disappear and stereo light comes on. Balanced up the 3 pot cores
and VRs for minimum noise etc.


electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse

Oh, that was you, Salim. I thought so, but your email didn't look familiar. Yes, thanks for
the Enigma cd, which was a nice surprise in the mail. Like it very much.
Always good measure to give the platter motor a shot of silicone spray lub, while you're in the
OMS.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"salim sm" wrote in message
om...
Thank you very much sir!! Disk spin and I'll tweak the trimpot a bit soon.

Btw how did you like the music from Enigma ?

Talk to you again soon (hopefully =)
Salim SM


"Stephen Sank" wrote in message ...
If the player gives up instantly, as if there was no disc in the tray, it's simply a faulty
optosensor(under right front of tray). If it spins up the disc & then gives up(which would
normally cause the player to auto eject), it may be that the laser output is just on the
borderline between ok & not ok. For this, you need a laser power meter, and it should
output
0.24mW. You need to block the optosensor(just a piece of masking or electrical tape over
the
hole at right front of tray), then power up the player to get the laser to run with no
disc.
The trimpot on the laser itself is the power adjust.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com

Hey, when the going gets tough, the tough goes to
sci.electronics.repair to find Master Wong. =)

Thanks for the help and hope all is well with you !

Best regards,
Salim SM


"Stephen Sank" wrote in message ...
Oh, that was you, Salim. I thought so, but your email didn't look familiar. Yes, thanks for
the Enigma cd, which was a nice surprise in the mail. Like it very much.
Always good measure to give the platter motor a shot of silicone spray lub, while you're in the
OMS.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com

Just an afterthought.
What does the 6V barttery do ?
With power to the standby transformer the front pannel selections stay as
selected.

"Stephen Sank" wrote in message
...
The 120V version of the 730 has a primary power switch on the back, but
the 120/240V version
does not. Not sure about the 220V version. The main power switch is the
touch-sensor button
on the front, which is powered by a small transformer/supply that's always
on(unless the rear
switch is off, on the 120v version at least). For this reason, it is not
possible to bring it
up on a variac, but I would not even consider that necessary. Other than
occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner), their
pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA) in
the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message
...
Incredably neavy lump. Unused for years and unknown history and mains
lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly clean
and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse

Just worked on an oms5ii last night & refreshed my memory. Two additional things- On both
large boards, chisel off all of the damn brown glue on both sides of each board. None of that
glue was needed in the first place, and it may be corroding stuff by now, and is most certainly
conductive. Secondly, resolder all cracked & suspect connections. Found a great number of
cracked joints on the servo board of this one.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"salim sm" wrote in message
om...
Hey, when the going gets tough, the tough goes to
sci.electronics.repair to find Master Wong. =)

Thanks for the help and hope all is well with you !

Best regards,
Salim SM


"Stephen Sank" wrote in message ...
Oh, that was you, Salim. I thought so, but your email didn't look familiar. Yes, thanks
for
the Enigma cd, which was a nice surprise in the mail. Like it very much.
Always good measure to give the platter motor a shot of silicone spray lub, while you're in
the
OMS.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com

All the battery pack does is remember the touch button selections when the unit gets totally
powered off. Pretty near useless function, esp. weighed against the probability of a battery
leakage mess.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message
news
Just an afterthought.
What does the 6V barttery do ?
With power to the standby transformer the front pannel selections stay as
selected.

"Stephen Sank" wrote in message
...
The 120V version of the 730 has a primary power switch on the back, but
the 120/240V version
does not. Not sure about the 220V version. The main power switch is the
touch-sensor button
on the front, which is powered by a small transformer/supply that's always
on(unless the rear
switch is off, on the 120v version at least). For this reason, it is not
possible to bring it
up on a variac, but I would not even consider that necessary. Other than
occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner), their
pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA) in
the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message
...
Incredably neavy lump. Unused for years and unknown history and mains
lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly clean
and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse

Hi, I have a 730 receiver with the controls of the front panel a little crazy at the begining, have to wait for 5 minutes to normalize. Can you help me with the origin of this problem?
Thanks in advance for any help.
Mikey.

On Wed, 31 May 2006 04:06:37 +0100, Mikey
wrote:


Hi, I have a 730 receiver with the controls of the front panel a little
crazy at the begining, have to wait for 5 minutes to normalize. Can you
help me with the origin of this problem?
Thanks in advance for any help.
Mikey.


Stephen Sank Wrote:
The 120V version of the 730 has a primary power switch on the back, but
the 120/240V version
does not. Not sure about the 220V version. The main power switch is
the touch-sensor button
on the front, which is powered by a small transformer/supply that's
always on(unless the rear
switch is off, on the 120v version at least). For this reason, it is
not possible to bring it
up on a variac, but I would not even consider that necessary. Other
than occassional minor
issues with the low voltage power supply(+/-15V for preamp & tuner),
their pretty damned
reliable. Just be prepared to replaced dozens of tiny lamps(14v/40mA)
in the front panel,
which are a bit challenging to get to.
The 730 is one of my favorite receivers in the world.

--
Stephen Sank, Owner & Ribbon Mic Restorer
Talking Dog Transducer Company
http://stephensank.com
5517 Carmelita Drive N.E.
Albuquerque, New Mexico [87111]
505-332-0336
Auth. Nakamichi & McIntosh servicer
Payments preferred through Paypal.com
"N Cook" wrote in message
...-
Incredably neavy lump. Unused for years and unknown history and mains
lead
is mildewed so
I wanted to insppect innards first and then power up on a variac.
Eventually twigged how to remove the top cover. Innards perfectly
clean and
healthy looking.
But now stumped - where on earth is the on/off switch ?

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse



-
Look for faulty electrolytic capacitors in the power supply. Chuck