Well, it is most unlikely that both the channels wood go down together now
I'd imagine.
Firstly, if you do not get a buzz when you touch the live of these
connections, then something is not as expected.
Sharp did tend to do stuff in funny ways though, and as has been said
elsewhere you need to find out what the turntable actually did. Was there,
for example, as I found on an old Teleton unit of similar vintage, a little
extra cable from the turntable to the circuit board? This little line
appeared to mute the pick up input in some way, presumably via a switch on
the pick up bearing or similar. I got the impression it used an optical
switch, but as the unit blew a power amp module shortly afterwards, I never
investigated further..

As for 8 track carts, most have seized up by now I'd imagine as the tape was
lubricated. Akai used to make an 8 track recorder which sounded quite good,
but the recording time per track was rubbish and the mechanics were designed
to wear out by the looks of it.

Quite how you cleaned things is hard to see.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"thanatoid" wrote in message
...
Hi all,

I have an old Sharp AM/FM receiver with an 8-track player. Made
in Japan ca. 1975 or something. It had a BSR turntable which was
broken. I removed the seized turntable, cleaned the whole unit,
sprayed all the pots, replaced the three little 6V bulbs behind
the black/green tuner window, and it is fabulous. It's built
like a tank and weighs a ton. The pots feel like military grade
stuff. The function switches are simply unbelievable. The front
panel is white (OK, bone now) with black controls, the box is
all wood with the then-standard "vinyl wood veneer".

I have a spare turntable which works perfectly. I intended to
connect it to the phono preamp of this receiver. I did, but I am
not getting sound. I am getting low-frequency pink noise, but no
audio signal. What is even stranger is that I hear one of the
channels "pop" when I dis/connect ONE of the two RCA audio
cables going into the phono preamp of the receiver. I tested all
the cables after extending them, and they are OK (see below).

I tried connecting the turntable signal to the line input, and
it DOES work. Of course, the signal is VERY low, but you CAN
hear the LP playing with the volume full up. So either I DID
somehow **** up the audio cable assembly (it tests OK though!)
or the phono preamp is partially or totally NG, in which case
there is probably nothing that can be done.

The line inputs can be used for a CD/DVD player, the receiver
works as a 4-speaker unit or 2 main/2 remote speakers, and it
sounds great. AM and line in are loud as hell, FM volume is
about 30% of that, but still usable.

Does anyone have any idea what I should do first? I want to
determine exactly /what/ in the chain from the *turntable audio
cables/cable extensions/original RCA plugs and cable/circuit
board* is NG.

(The phonograph audio cables were only long enough to reach the
bottom of the turntable, which was 3 inches above the main
circuit board, now they have to reach to the back and out of the
unit, so I had to add about 8 inches of cable - but I tested the
cables, both channels, live /and/ ground, and I made NO mistakes
- everything was connected/soldered correctly.

If the phono preamp is dead, it's dead. The unit is still a
/great/ AM (and decent FM) receiver and line-in amplifier,
handles TWO sets of stereo speakers, and it will outlast all of
us. I have yet to find an 8-track cartridge, but the mechanism
and all the belts seem fine. Plus I don't think anyone needs an
8-track deck, while /quite/ a few people might enjoy having a
receiver with a phono preamp. Unless the phono preamp IS dead,
of course. But maybe someone can help me determine if it
actually IS dead...

I /tried/ to make this short, really!

Any advice will be greatly appreciated.

--
Any mental activity is easy if it need not be subjected to
reality.

"Brian Gaff" wrote in
:

Thanks for replying.

Well, it is most unlikely that both the channels woold go
down together now I'd imagine.

Right.

Firstly, if you do not get a buzz when you touch the live
of these connections, then something is not as expected.
Sharp did tend to do stuff in funny ways though, and as
has been said
elsewhere you need to find out what the turntable actually
did. Was there, for example, as I found on an old Teleton
unit of similar vintage, a little extra cable from the
turntable to the circuit board?

No, there are two (grey and brown, thankfully labeled L and R)
RCA cables which plugged into the bottom of the BSR turntable
where the 4 wires from the cartridge were soldered to the other
side of the 2 RCA connector. I cut them and extended them. And
something went wrong, see below.

This little line appeared
to mute the pick up input in some way, presumably via a
switch on the pick up bearing or similar. I got the
impression it used an optical switch, but as the unit blew
a power amp module shortly afterwards, I never investigated
further..

No, someone else suggested the muting device, but I do not think
this unit had that... It is an amazing piece of vintage quality
TODAY but it was a cheapish thing in its day...

As for 8 track carts, most have seized up by now I'd
imagine as the tape was lubricated. Akai used to make an 8
track recorder which sounded quite good, but the recording
time per track was rubbish and the mechanics were designed
to wear out by the looks of it.

I am curious to see what the deal is here, IF I can find an 8-
track cart. (About 15 yrs ago I knew a guy who had an 8-track of
Lou Reed's "Metal Machine Music" !!!!)

Quite how you cleaned things is hard to see.

I am good at cleaning stuff, and I have a pro circuit board
cleaner. I did not use WD-40 - although I /have/ done so in the
past, with perfect results.

-- Update (very long, I apologize!) --

First of all, many thanks to all who replied. It is very much
appreciated.

Now for the /bad/ part.

Something one person mentioned in his reply made me remember a
rather *crucial* detail which I had forgotten (I am not
completely senile yet, but I have been /incredibly/ busy for the
last few weeks, and my brain is running out of RAM).

It is this: BEFORE I removed the BSR turntable, I DID check to
see whether there was AUDIO SIGNAL coming from it. There was,
loud and clear - when I touched the stylus, it sounded like an
earthquake. Very little "system noise", too.

The turntable itself was "seized" - after I have (with some
violence) managed to take it apart, I saw that the 2 main cog
wheels of the belt-less motor were practically frozen together
at a bizarre angle and would NOT budge. I have NO idea how that
happened - and the 4" screwdriver shaft, 2 children's plastic
letters with magnets, and assorted bits of 30+ year old food I
found inside the receiver could NOT have had anything to do with
it, either, since the BSR motor was fairly well enclosed within
the /incredibly/ complicated mechanical design (a changer).

Now that I have remembered this, it is obvious I screwed
something up. I have never seen a ceramic cartridge, but I am
99.99% positive that BOTH the BSR and the Sony (ca. 1990)
turntable carts are magnetic. So, since I have no signal but
weird pink noise, I must have screwed up the cables. Or do you
think I may have destroyed the preamp?

(This may be a good moment to mention that I am using the term
"phono preamp" in a generic sense. I always thought a phono
preamp might be/would be a small enclosed piece of electronics,
but in this receiver, it appears to be a part of the main
circuit board - the two original (and now extended) cables from
the BSR turntable stylus/arm are soldered right onto the circuit
board, and go who-knows-where - presumably, into components
which make up this receiver's "phone preamp" section.)

(THIS may /also/ be a good moment to mention that while I have
had some disastrous luck with simple things and astoundingly
good luck with complicated things, I am NOT a technician, and do
not own an oscilloscope - I check connections with two gator
clips connected to a 1.5V battery with a flashlight bulb, and
after over 30 years of "considering it", I finally bought a five
dollar "voltmeter" which /appears/ to work - I found out a cheap
110V/22V AC/DC adapter outputs 25VDC when set to 12V output
[when the input voltage is set to 110V] and 12.5VDC from its 9V
setting [when the input voltage is set to 110V (it is 110V
here)]. The Sony turntable (originally a component of a system,
with a tiny power connector which plugs into the back of the
main system unit and where I found out 12VDC is output) is
running on a supposedly "regulated" fancy Radio Shack AC/DC
adapter which puts out 11.8V DC. (When I reverse the polarity,
the turntable spins backwards.)

If anyone has read this far, please accept my deep thanks for
your patience. I can't write more concisely - I realize it's an
illness.

Anyway - the question now is WHAT did I do to mess things up?
Since I consider the receiver largely indestructible, I do not
think I have *destroyed* anything, not to mention the voltages
involved are totally minuscule and it being a solid state unit -
as the front panel proudly states ;-) - there is little danger
of blowing it up. Plus everything else works.

My plan is as follows:

1. Cut the original "BSR cartridge/turntable to the main circuit
board" cables, strip ends.
2. Attach gator clips to them and connect to the Sony turntable
output cable.
3. Hopefully, hear sound. Extend cables again, making SURE I
don't screw up this time.

If I hear no sound, I will connect the 4 very thin cables from
the original BSR cartridge (I saved the cart assembly and cables
before I saw the turntable was connected to the circuit board
with 2 standard cables with RCA plugs) to the cut cables leading
to the circuit board and see if I hear anything. If I do, I will
post for more advice.

But for now, my question is:

If after doing all this, I still get the /same/ pink noise (NOT
hum - strange, huh?) and get NO audio, WHAT do I do?

Thank you /very much/ for your patience, and my apologies for
having forgotten a crucial part of the puzzle. Further help will
be greatly appreciated. If anyone wants to see pix of the 2
cartridges or the circuit board where the phono audio cables are
soldered into it, I can post them to photobucket or something,
OR a binary group if you have binaries access.

The replies are different in every one of the 5 groups, so I
will post this followup to each group separately. I don't really
understand how crossposting works, since I never do it, and
eternal september /may/ be "funny" about crossposting to boot.


--
Any mental activity is easy if it need not be subjected to
reality.

Pink or some noise is possible if high sensitivity inputs are terminated
incorrectly. One needs to be careful in case the transistors here are a bit
on the sensitive side. I had Riaa amp transistors go crackly on thePioneer I
had, but a cheap Tandy replacement soldered in was fine.
Like we said, its odd that neither channel gives anything but hiss, as
lighteneing does not usually strike twice.

I guess you could have shorted the inputs out in some way though. Its a pity
you don't have the circuit as this might help.
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"thanatoid" wrote in message
...
"Brian Gaff" wrote in
:

Thanks for replying.

Well, it is most unlikely that both the channels woold go
down together now I'd imagine.

Right.

Firstly, if you do not get a buzz when you touch the live
of these connections, then something is not as expected.
Sharp did tend to do stuff in funny ways though, and as
has been said
elsewhere you need to find out what the turntable actually
did. Was there, for example, as I found on an old Teleton
unit of similar vintage, a little extra cable from the
turntable to the circuit board?

No, there are two (grey and brown, thankfully labeled L and R)
RCA cables which plugged into the bottom of the BSR turntable
where the 4 wires from the cartridge were soldered to the other
side of the 2 RCA connector. I cut them and extended them. And
something went wrong, see below.

This little line appeared
to mute the pick up input in some way, presumably via a
switch on the pick up bearing or similar. I got the
impression it used an optical switch, but as the unit blew
a power amp module shortly afterwards, I never investigated
further..

No, someone else suggested the muting device, but I do not think
this unit had that... It is an amazing piece of vintage quality
TODAY but it was a cheapish thing in its day...

As for 8 track carts, most have seized up by now I'd
imagine as the tape was lubricated. Akai used to make an 8
track recorder which sounded quite good, but the recording
time per track was rubbish and the mechanics were designed
to wear out by the looks of it.

I am curious to see what the deal is here, IF I can find an 8-
track cart. (About 15 yrs ago I knew a guy who had an 8-track of
Lou Reed's "Metal Machine Music" !!!!)

Quite how you cleaned things is hard to see.

I am good at cleaning stuff, and I have a pro circuit board
cleaner. I did not use WD-40 - although I /have/ done so in the
past, with perfect results.

-- Update (very long, I apologize!) --

First of all, many thanks to all who replied. It is very much
appreciated.

Now for the /bad/ part.

Something one person mentioned in his reply made me remember a
rather *crucial* detail which I had forgotten (I am not
completely senile yet, but I have been /incredibly/ busy for the
last few weeks, and my brain is running out of RAM).

It is this: BEFORE I removed the BSR turntable, I DID check to
see whether there was AUDIO SIGNAL coming from it. There was,
loud and clear - when I touched the stylus, it sounded like an
earthquake. Very little "system noise", too.

The turntable itself was "seized" - after I have (with some
violence) managed to take it apart, I saw that the 2 main cog
wheels of the belt-less motor were practically frozen together
at a bizarre angle and would NOT budge. I have NO idea how that
happened - and the 4" screwdriver shaft, 2 children's plastic
letters with magnets, and assorted bits of 30+ year old food I
found inside the receiver could NOT have had anything to do with
it, either, since the BSR motor was fairly well enclosed within
the /incredibly/ complicated mechanical design (a changer).

Now that I have remembered this, it is obvious I screwed
something up. I have never seen a ceramic cartridge, but I am
99.99% positive that BOTH the BSR and the Sony (ca. 1990)
turntable carts are magnetic. So, since I have no signal but
weird pink noise, I must have screwed up the cables. Or do you
think I may have destroyed the preamp?

(This may be a good moment to mention that I am using the term
"phono preamp" in a generic sense. I always thought a phono
preamp might be/would be a small enclosed piece of electronics,
but in this receiver, it appears to be a part of the main
circuit board - the two original (and now extended) cables from
the BSR turntable stylus/arm are soldered right onto the circuit
board, and go who-knows-where - presumably, into components
which make up this receiver's "phone preamp" section.)

(THIS may /also/ be a good moment to mention that while I have
had some disastrous luck with simple things and astoundingly
good luck with complicated things, I am NOT a technician, and do
not own an oscilloscope - I check connections with two gator
clips connected to a 1.5V battery with a flashlight bulb, and
after over 30 years of "considering it", I finally bought a five
dollar "voltmeter" which /appears/ to work - I found out a cheap
110V/22V AC/DC adapter outputs 25VDC when set to 12V output
[when the input voltage is set to 110V] and 12.5VDC from its 9V
setting [when the input voltage is set to 110V (it is 110V
here)]. The Sony turntable (originally a component of a system,
with a tiny power connector which plugs into the back of the
main system unit and where I found out 12VDC is output) is
running on a supposedly "regulated" fancy Radio Shack AC/DC
adapter which puts out 11.8V DC. (When I reverse the polarity,
the turntable spins backwards.)

If anyone has read this far, please accept my deep thanks for
your patience. I can't write more concisely - I realize it's an
illness.

Anyway - the question now is WHAT did I do to mess things up?
Since I consider the receiver largely indestructible, I do not
think I have *destroyed* anything, not to mention the voltages
involved are totally minuscule and it being a solid state unit -
as the front panel proudly states ;-) - there is little danger
of blowing it up. Plus everything else works.

My plan is as follows:

1. Cut the original "BSR cartridge/turntable to the main circuit
board" cables, strip ends.
2. Attach gator clips to them and connect to the Sony turntable
output cable.
3. Hopefully, hear sound. Extend cables again, making SURE I
don't screw up this time.

If I hear no sound, I will connect the 4 very thin cables from
the original BSR cartridge (I saved the cart assembly and cables
before I saw the turntable was connected to the circuit board
with 2 standard cables with RCA plugs) to the cut cables leading
to the circuit board and see if I hear anything. If I do, I will
post for more advice.

But for now, my question is:

If after doing all this, I still get the /same/ pink noise (NOT
hum - strange, huh?) and get NO audio, WHAT do I do?

Thank you /very much/ for your patience, and my apologies for
having forgotten a crucial part of the puzzle. Further help will
be greatly appreciated. If anyone wants to see pix of the 2
cartridges or the circuit board where the phono audio cables are
soldered into it, I can post them to photobucket or something,
OR a binary group if you have binaries access.

The replies are different in every one of the 5 groups, so I
will post this followup to each group separately. I don't really
understand how crossposting works, since I never do it, and
eternal september /may/ be "funny" about crossposting to boot.


--
Any mental activity is easy if it need not be subjected to
reality.

"Brian Gaff" wrote in
:

snip

I guess you could have shorted the inputs out in some way
though. Its a pity you don't have the circuit as this might
help. Brian

There are service manuals listed on the web, but they are $15
and up. I am fixing this Sharp to sell it - I do not need it,
although it is probably a better 20-30W/side power amp than
anything you can buy now for under $100 or so. And it has
outputs for 2 sets of speakers - very nice feature. I doubt I
will get much - if ANYTHING - for it, but I hate throwing nice
old stuff away. OTOH, people just do NOT appreciate treasures
like this. Someone just GAVE it to me.

I may end up keeping it, it is cute as hell, and works great as
AM radio or line-in amplifier.

I have another (better than the Sony) turntable plugged into a
perfectly good stereo which I am using to transfer old vinyl to
mp3. (My old ears can't hear the difference much anymore.)

Thanks for your comments.



--
Any mental activity is easy if it need not be subjected to
reality.

"thanatoid" wrote in message
...
Hi all,

I have an old Sharp AM/FM receiver with an 8-track player. Made
in Japan ca. 1975 or something. It had a BSR turntable which was
broken. I removed the seized turntable, cleaned the whole unit,
sprayed all the pots, replaced the three little 6V bulbs behind
the black/green tuner window, and it is fabulous. It's built
like a tank and weighs a ton. The pots feel like military grade
stuff. The function switches are simply unbelievable. The front
panel is white (OK, bone now) with black controls, the box is
all wood with the then-standard "vinyl wood veneer".

I have a spare turntable which works perfectly. I intended to
connect it to the phono preamp of this receiver. I did, but I am
not getting sound. I am getting low-frequency pink noise, but no
audio signal. What is even stranger is that I hear one of the
channels "pop" when I dis/connect ONE of the two RCA audio
cables going into the phono preamp of the receiver. I tested all
the cables after extending them, and they are OK (see below).

I tried connecting the turntable signal to the line input, and
it DOES work. Of course, the signal is VERY low, but you CAN
hear the LP playing with the volume full up. So either I DID
somehow **** up the audio cable assembly (it tests OK though!)
or the phono preamp is partially or totally NG, in which case
there is probably nothing that can be done.

The line inputs can be used for a CD/DVD player, the receiver
works as a 4-speaker unit or 2 main/2 remote speakers, and it
sounds great. AM and line in are loud as hell, FM volume is
about 30% of that, but still usable.

Does anyone have any idea what I should do first? I want to
determine exactly /what/ in the chain from the *turntable audio
cables/cable extensions/original RCA plugs and cable/circuit
board* is NG.

(The phonograph audio cables were only long enough to reach the
bottom of the turntable, which was 3 inches above the main
circuit board, now they have to reach to the back and out of the
unit, so I had to add about 8 inches of cable - but I tested the
cables, both channels, live /and/ ground, and I made NO mistakes
- everything was connected/soldered correctly.

If the phono preamp is dead, it's dead. The unit is still a
/great/ AM (and decent FM) receiver and line-in amplifier,
handles TWO sets of stereo speakers, and it will outlast all of
us. I have yet to find an 8-track cartridge, but the mechanism
and all the belts seem fine. Plus I don't think anyone needs an
8-track deck, while /quite/ a few people might enjoy having a
receiver with a phono preamp. Unless the phono preamp IS dead,
of course. But maybe someone can help me determine if it
actually IS dead...

I /tried/ to make this short, really!

Any advice will be greatly appreciated.

--
Any mental activity is easy if it need not be subjected to
reality.


Perhaps the stylus on the replacement turntable is not quite seated
properly. This would produce your symptom. No sound when plugged into the
(ceramic) phono input, hear a pop w/ unplug, hear low sound on another
input.

I'm presuming your original turntable had a ceramic cartridge, but it would
help to know if this is true; also what kind of cartridge is in your
replacement table.

Mark Z.

Mark Z.

"Mark Zacharias" wrote in
:

Thanks for the reply.

snip

Perhaps the stylus on the replacement turntable is not
quite seated properly.

It works perfectly with its original system (see below).

This would produce your symptom. No
sound when plugged into the (ceramic) phono input, hear a
pop w/ unplug, hear low sound on another input.

Hmm. The two cartridges, while different, both appear to be
magnetic. I can post photos (see below).

I'm presuming your original turntable had a ceramic
cartridge, but it would help to know if this is true; also
what kind of cartridge is in your replacement table.

I am 99.99% sure both are magnetic, but I can post photos.

Please take the time to read the following.

-- Update (very long, I apologize!) --

First of all, many thanks to all who replied. It is very much
appreciated.

Now for the /bad/ part.

Something one person mentioned in his reply made me remember a
rather *crucial* detail which I had forgotten (I am not
completely senile yet, but I have been /incredibly/ busy for the
last few weeks, and my brain is running out of RAM).

It is this: BEFORE I removed the BSR turntable, I DID check to
see whether there was AUDIO SIGNAL coming from it. There was,
loud and clear - when I touched the stylus, it sounded like an
earthquake. Very little "system noise", too.

The turntable itself was "seized" - after I have (with some
violence) managed to take it apart, I saw that the 2 main cog
wheels of the belt-less motor were practically frozen together
at a bizarre angle and would NOT budge. I have NO idea how that
happened - and the 4" screwdriver shaft, 2 children's plastic
letters with magnets, and assorted bits of 30+ year old food I
found inside the receiver could NOT have had anything to do with
it, either, since the BSR motor was fairly well enclosed within
the /incredibly/ complicated mechanical design (a changer).

Now that I have remembered this, it is obvious I screwed
something up. I have never seen a ceramic cartridge, but I am
99.99% positive that BOTH the BSR and the Sony (ca. 1990)
turntable carts are magnetic. So, since I have no signal but
weird pink noise, I must have screwed up the cables. Or do you
think I may have destroyed the preamp?

(This may be a good moment to mention that I am using the term
"phono preamp" in a generic sense. I always thought a phono
preamp might be/would be a small enclosed piece of electronics,
but in this receiver, it appears to be a part of the main
circuit board - the two original (and now extended) cables from
the BSR turntable stylus/arm are soldered right onto the circuit
board, and go who-knows-where - presumably, into components
which make up this receiver's "phone preamp" section.)

(THIS may /also/ be a good moment to mention that while I have
had some disastrous luck with simple things and astoundingly
good luck with complicated things, I am NOT a technician, and do
not own an oscilloscope - I check connections with two gator
clips connected to a 1.5V battery with a flashlight bulb, and
after over 30 years of "considering it", I finally bought a five
dollar "voltmeter" which /appears/ to work - I found out a cheap
110V/22V AC/DC adapter outputs 25VDC when set to 12V output
[when the input voltage is set to 110V] and 12.5VDC from its 9V
setting [when the input voltage is set to 110V (it is 110V
here)]. The Sony turntable (originally a component of a system,
with a tiny power connector which plugs into the back of the
main system unit and where I found out 12VDC is output) is
running on a supposedly "regulated" fancy Radio Shack AC/DC
adapter which puts out 11.8V DC. (When I reverse the polarity,
the turntable spins backwards.)

If anyone has read this far, please accept my deep thanks for
your patience. I can't write more concisely - I realize it's an
illness.

Anyway - the question now is WHAT did I do to mess things up?
Since I consider the receiver largely indestructible, I do not
think I have *destroyed* anything, not to mention the voltages
involved are totally minuscule and it being a solid state unit -
as the front panel proudly states ;-) - there is little danger
of blowing it up. Plus everything else works.

My plan is as follows:

1. Cut the original "BSR cartridge/turntable to the main circuit
board" cables, strip ends.
2. Attach gator clips to them and connect to the Sony turntable
output cable.
3. Hopefully, hear sound. Extend cables again, making SURE I
don't screw up this time.

If I hear no sound, I will connect the 4 very thin cables from
the original BSR cartridge (I saved the cart assembly and cables
before I saw the turntable was connected to the circuit board
with 2 standard cables with RCA plugs) to the cut cables leading
to the circuit board and see if I hear anything. If I do, I will
post for more advice.

But for now, my question is:

If after doing all this, I still get the /same/ pink noise (NOT
hum - strange, huh?) and get NO audio, WHAT do I do?

Thank you /very much/ for your patience, and my apologies for
having forgotten a crucial part of the puzzle. Further help will
be greatly appreciated. If anyone wants to see pix of the 2
cartridges or the circuit board where the phono audio cables are
soldered into it, I can post them to photobucket or something,
OR a binary group if you have binaries access.

The replies are different in every one of the 5 groups, so I
will post this followup to each group separately. I don't really
understand how crossposting works, since I never do it, and
eternal september /may/ be "funny" about crossposting to boot.


--
Any mental activity is easy if it need not be subjected to
reality.

Hello,

while I don't know your specific Sharp receiver (you did not specify
the model number) many 'compact systems' with BSR changers used ceramic
cartridges that give a line level output, so this receiver may not have
a phono preamp at all.

Regards,
Tim Schwartz
Bristol Electronics


On 9/8/2010 7:12 PM, thanatoid wrote:
Hi all,

I have an old Sharp AM/FM receiver with an 8-track player. Made
in Japan ca. 1975 or something. It had a BSR turntable which was
broken. I removed the seized turntable, cleaned the whole unit,
sprayed all the pots, replaced the three little 6V bulbs behind
the black/green tuner window, and it is fabulous. It's built
like a tank and weighs a ton. The pots feel like military grade
stuff. The function switches are simply unbelievable. The front
panel is white (OK, bone now) with black controls, the box is
all wood with the then-standard "vinyl wood veneer".

I have a spare turntable which works perfectly. I intended to
connect it to the phono preamp of this receiver. I did, but I am
not getting sound. I am getting low-frequency pink noise, but no
audio signal. What is even stranger is that I hear one of the
channels "pop" when I dis/connect ONE of the two RCA audio
cables going into the phono preamp of the receiver. I tested all
the cables after extending them, and they are OK (see below).

I tried connecting the turntable signal to the line input, and
it DOES work. Of course, the signal is VERY low, but you CAN
hear the LP playing with the volume full up. So either I DID
somehow **** up the audio cable assembly (it tests OK though!)
or the phono preamp is partially or totally NG, in which case
there is probably nothing that can be done.

The line inputs can be used for a CD/DVD player, the receiver
works as a 4-speaker unit or 2 main/2 remote speakers, and it
sounds great. AM and line in are loud as hell, FM volume is
about 30% of that, but still usable.

Does anyone have any idea what I should do first? I want to
determine exactly /what/ in the chain from the *turntable audio
cables/cable extensions/original RCA plugs and cable/circuit
board* is NG.

(The phonograph audio cables were only long enough to reach the
bottom of the turntable, which was 3 inches above the main
circuit board, now they have to reach to the back and out of the
unit, so I had to add about 8 inches of cable - but I tested the
cables, both channels, live /and/ ground, and I made NO mistakes
- everything was connected/soldered correctly.

If the phono preamp is dead, it's dead. The unit is still a
/great/ AM (and decent FM) receiver and line-in amplifier,
handles TWO sets of stereo speakers, and it will outlast all of
us. I have yet to find an 8-track cartridge, but the mechanism
and all the belts seem fine. Plus I don't think anyone needs an
8-track deck, while /quite/ a few people might enjoy having a
receiver with a phono preamp. Unless the phono preamp IS dead,
of course. But maybe someone can help me determine if it
actually IS dead...

I /tried/ to make this short, really!

Any advice will be greatly appreciated.

Tim Schwartz wrote in
:

Thanks for your reply.

while I don't know your specific Sharp receiver (you
did not specify
the model number) many 'compact systems' with BSR changers
used ceramic cartridges that give a line level output, so
this receiver may not have a phono preamp at all.

AHA! This WOULD explain /everything/! (Including WHY there does
NOT appear to be an identifiable "phone preamp", just the 2
cables going into the circuitry.)

The model number is SG-164U.
Can you confirm the ceramic cart thing?

And is there ANYTHING I can do to make a magnetic cartridge work
with this unit? (Buying a phono preamp is OOTQ, it would cost
more than a new DVD player, but perhaps I could make one? Would
you happen to have a schematic/link to one?)

For /all/ the gory details:

-- Update (very long, I apologize!) --

First of all, many thanks to all who replied. It is very much
appreciated.

Now for the /bad/ part.

Something one person mentioned in his reply made me remember a
rather *crucial* detail which I had forgotten (I am not
completely senile yet, but I have been /incredibly/ busy for the
last few weeks, and my brain is running out of RAM).

It is this: BEFORE I removed the BSR turntable, I DID check to
see whether there was AUDIO SIGNAL coming from it. There was,
loud and clear - when I touched the stylus, it sounded like an
earthquake. Very little "system noise", too.

The turntable itself was "seized" - after I have (with some
violence) managed to take it apart, I saw that the 2 main cog
wheels of the belt-less motor were practically frozen together
at a bizarre angle and would NOT budge. I have NO idea how that
happened - and the 4" screwdriver shaft, 2 children's plastic
letters with magnets, and assorted bits of 30+ year old food I
found inside the receiver could NOT have had anything to do with
it, either, since the BSR motor was fairly well enclosed within
the /incredibly/ complicated mechanical design (a changer).

Now that I have remembered this, it is obvious I screwed
something up. I have never seen a ceramic cartridge, but I am
99.99% positive that BOTH the BSR and the Sony (ca. 1990)
turntable carts are magnetic. So, since I have no signal but
weird pink noise, I must have screwed up the cables. Or do you
think I may have destroyed the preamp?

(This may be a good moment to mention that I am using the term
"phono preamp" in a generic sense. I always thought a phono
preamp might be/would be a small enclosed piece of electronics,
but in this receiver, it appears to be a part of the main
circuit board - the two original (and now extended) cables from
the BSR turntable stylus/arm are soldered right onto the circuit
board, and go who-knows-where - presumably, into components
which make up this receiver's "phone preamp" section.)

(THIS may /also/ be a good moment to mention that while I have
had some disastrous luck with simple things and astoundingly
good luck with complicated things, I am NOT a technician, and do
not own an oscilloscope - I check connections with two gator
clips connected to a 1.5V battery with a flashlight bulb, and
after over 30 years of "considering it", I finally bought a five
dollar "voltmeter" which /appears/ to work - I found out a cheap
110V/22V AC/DC adapter outputs 25VDC when set to 12V output
[when the input voltage is set to 110V] and 12.5VDC from its 9V
setting [when the input voltage is set to 110V (it is 110V
here)]. The Sony turntable (originally a component of a system,
with a tiny power connector which plugs into the back of the
main system unit and where I found out 12VDC is output) is
running on a supposedly "regulated" fancy Radio Shack AC/DC
adapter which puts out 11.8V DC. (When I reverse the polarity,
the turntable spins backwards.)

If anyone has read this far, please accept my deep thanks for
your patience. I can't write more concisely - I realize it's an
illness.

Anyway - the question now is WHAT did I do to mess things up?
Since I consider the receiver largely indestructible, I do not
think I have *destroyed* anything, not to mention the voltages
involved are totally minuscule and it being a solid state unit -
as the front panel proudly states ;-) - there is little danger
of blowing it up. Plus everything else works.

My plan is as follows:

1. Cut the original "BSR cartridge/turntable to the main circuit
board" cables, strip ends.
2. Attach gator clips to them and connect to the Sony turntable
output cable.
3. Hopefully, hear sound. Extend cables again, making SURE I
don't screw up this time.

If I hear no sound, I will connect the 4 very thin cables from
the original BSR cartridge (I saved the cart assembly and cables
before I saw the turntable was connected to the circuit board
with 2 standard cables with RCA plugs) to the cut cables leading
to the circuit board and see if I hear anything. If I do, I will
post for more advice.

But for now, my question is:

If after doing all this, I still get the /same/ pink noise (NOT
hum - strange, huh?) and get NO audio, WHAT do I do?

Thank you /very much/ for your patience, and my apologies for
having forgotten a crucial part of the puzzle. Further help will
be greatly appreciated. If anyone wants to see pix of the 2
cartridges or the circuit board where the phono audio cables are
soldered into it, I can post them to photobucket or something,
OR a binary group if you have binaries access.

The replies are different in every one of the 5 groups, so I
will post this followup to each group separately. I don't really
understand how crossposting works, since I never do it, and
eternal september /may/ be "funny" about crossposting to boot.


--
Any mental activity is easy if it need not be subjected to
reality.

"thanatoid" wrote

And is there ANYTHING I can do to make a magnetic cartridge work
with this unit? (Buying a phono preamp is OOTQ, it would cost
more than a new DVD player, but perhaps I could make one? Would
you happen to have a schematic/link to one?)


Low-cost phono pre-amps are readily available. As you appear to live in the
US could I suggest looking at what Radio Shack has to offer? You should be
able to get a simple phono pre-amp on a small PCB (no case, connectors or
power supply) for a *lot* less than the cost of a DVD player and for little
more than the retail cost of the components.

David.

"Peter Larsen" wrote in
k:

snip

Are you sure the original turntable had a magnetic
cartridge? - and if so, did it contain a preamp for it?

Thanks for replying.

I'm /not at all/ sure now.

Someone in another group just said he is almost certain the
Sharp units of that vintage used
ceramic cartridges, which would explain /everything/.

Also, please see below (heavily edited for you ;-) :

(...)

Something one person mentioned in his reply made me remember a
rather *crucial* detail which I had forgotten (I am not
completely senile yet, but I have been /incredibly/ busy for the
last few weeks, and my brain is running out of RAM).

It is this: BEFORE I removed the BSR turntable, I DID check to
see whether there was AUDIO SIGNAL coming from it. There was,
loud and clear - when I touched the stylus, it sounded like an
earthquake. Very little "system noise", too.

Now that I have remembered this, it is obvious I screwed
something up. I have never seen a ceramic cartridge, but I am
99.99% positive that BOTH the BSR and the Sony (ca. 1990)
turntable carts are magnetic. So, since I have no signal but
weird pink noise, I must have screwed up the cables. Or do you
think I may have destroyed the preamp?

(This may be a good moment to mention that I am using the term
"phono preamp" in a generic sense. I always thought a phono
preamp might be/would be a small enclosed piece of electronics,
but in this receiver, it appears to be a part of the main
circuit board - the two original (and now extended) cables from
the BSR turntable stylus/arm are soldered right onto the circuit
board, and go who-knows-where - presumably, into components
which make up this receiver's "phone preamp" section.)

(...)



--
Any mental activity is easy if it need not be subjected to
reality.