Pioneer sx-727 radio dead

[[email protected]]

I have a pioneer sx-727 receiver, I'm the original owner (33 years).
Recently the radio stopped working.
Everything else works great.
FM, AM no difference does NOT work.
The tuning meter does not move as I turn the tuning dial.
If I turn the volume up, I can hear some static thru the speakers.
Occasionally the radio will spontaneously work for a while,
and then return to this dead mode.
All the other inputs cd, turntable work fine.
Any ideas what the problem might be?
Thanks.

 

[Bob Shuman]

Sounds like something is intermittent in the radio section (assumes
amplifier/auxiliary input/tape/etc. all are still working fine). I'd start
by looking for cold/broken solder connections under a magnifying. Or
alternatively, if that does not work and you can get at the board safely
while the unit is powered up, you can try pushing at various points with a
wooden dowel or similar non-conductive item. This may help you isolate the
area to take a closer look.

If these do not help, then you'll either need a schematic, a volt meter,
scope, and some troubleshooting skills to check the power supply voltages at
key points and then follow the signal through the radio section or take it
to someone to do the work for you.

Bob

 

[[email protected]]

OK I took the thing apart and sure enough, there was a sanyo 313E
mounted on a V shaped piece of metal(heatsink?). When I tapped
gently on the metal, everything now works fine.
The small board in question is AWR-011A, which according
to the schematic is the power supply unit.
I would think that if this was the roblem it would effect
everything, not just the radio.
Anyway I will run it for awhile with the case open,
and see if the problem recurs.

 

[Mark D. Zacharias]

OK I took the thing apart and sure enough, there was a sanyo 313E
mounted on a V shaped piece of metal(heatsink?). When I tapped
gently on the metal, everything now works fine.
The small board in question is AWR-011A, which according
to the schematic is the power supply unit.
I would think that if this was the roblem it would effect
everything, not just the radio.
Anyway I will run it for awhile with the case open,
and see if the problem recurs.

Sounds like something is intermittent in the radio section (assumes
amplifier/auxiliary input/tape/etc. all are still working fine). I'd start
by looking for cold/broken solder connections under a magnifying. Or
alternatively, if that does not work and you can get at the board safely
while the unit is powered up, you can try pushing at various points with a
wooden dowel or similar non-conductive item. This may help you isolate the
area to take a closer look.

If these do not help, then you'll either need a schematic, a volt meter,
scope, and some troubleshooting skills to check the power supply voltages
at
key points and then follow the signal through the radio section or take it
to someone to do the work for you.

Bob






- Show quoted text -

Resolder the 313 regulator.

Mark Z.

 

[Mr. Land]

I have a pioneer sx-727 receiver, I'm the original owner (33 years).
Recently the radio stopped working.
Everything else works great.
FM, AM  no difference does NOT work.
The tuning meter does not move as I turn the tuning dial.
If I turn the volume up, I can hear some static thru the speakers.
Occasionally the radio will spontaneously work for a while,
and then return to this dead mode.
All the other inputs cd, turntable work fine.
Any ideas what the problem might be?
Thanks.

I worked on a bunch of these in a previous life.

It has been a long time, but I seem to remember a common problem of a
voltage regulator in the power supply section becoming thermally/
mechanically/whateverly intermittent. If the entire tuner section is
going dead, this might be worth looking for. Seems a reasonable
candidate if the tuner works occasionally as you stated.

Look for a 3-pin voltage regulator in a TO-220 case - might not even
be on a heatsink. Try tapping it with something non-conductive, or
heating it, or freezing it, or, you might actually measure its output
voltage. Worth a quick look, I suppose.

 

[Mr. Land]

I worked on a bunch of these in a previous life.

It has been a long time, but I seem to remember a common problem of a
voltage regulator in the power supply section becoming thermally/
mechanically/whateverly intermittent.  If the entire tuner section is
going dead, this might be worth looking for.  Seems a reasonable
candidate if the tuner works occasionally as you stated.

Look for a 3-pin voltage regulator in a TO-220 case - might not even
be on a heatsink.  Try tapping it with something non-conductive, or
heating it, or freezing it, or, you might actually measure its output
voltage.  Worth a quick look, I suppose.

Whoops, sorry, I missed the last reply or two. I guess mine was
redundant/unnecessary.

 

[Chuck]

OK I took the thing apart and sure enough, there was a sanyo 313E
mounted on a V shaped piece of metal(heatsink?). When I tapped
gently on the metal, everything now works fine.
The small board in question is AWR-011A, which according
to the schematic is the power supply unit.
I would think that if this was the roblem it would effect
everything, not just the radio.
Anyway I will run it for awhile with the case open,
and see if the problem recurs.

The 2SD313 transistor itself was know for going intermittent. Replace
the transistor. A NTE198 or 2SD613 works fine. Chuck

 

[[email protected]]

I have left the case open, and have the thing sitting on a shelf
vertically.
It worked flawlessly for about 3 days, then spontaneouslt the radio
went dead again.
I ever so gently tapped the heatsink that this transistor is on, and
once
again everything is fine. I have not lifted the board yet to look at
the solder
underneath. However I'm beginning to think that it is the transistor
itself
that is the problem. Can I find the exact replacement at radio shack?
If I'm going to lift the board, I'm thinking it's probably makes sense
to replace the
device.

Thanks

 

[Mark D. Zacharias]

I have left the case open, and have the thing sitting on a shelf
vertically.
It worked flawlessly for about 3 days, then spontaneouslt the radio
went dead again.
I ever so gently tapped the heatsink that this transistor is on, and
once
again everything is fine. I have not lifted the board yet to look at
the solder
underneath. However I'm beginning to think that it is the transistor
itself
that is the problem. Can I find the exact replacement at radio shack?
If I'm going to lift the board, I'm thinking it's probably makes sense
to replace the
device.

Thanks

I strongly suggest you find and fix the cold solder connection that
caused the fault. Or if the transistor is intermittant, replace it.

--

JANA
_____


OK I took the thing apart and sure enough, there was a sanyo 313E
mounted on a V shaped piece of metal(heatsink?). When I tapped
gently on the metal, everything now works fine.
The small board in question is AWR-011A, which according
to the schematic is the power supply unit.
I would think that if this was the roblem it would effect
everything, not just theradio.
Anyway I will run it for awhile with the case open,
and see if the problem recurs.





- Show quoted text -

Just resolder the transistor. You will see that the solder connections there
have ring cracks from age and heating / cooling over the course of time.
Common problem.

Mark Z.

 

[[email protected]]

I have left the case open, and have the thing sitting on a shelf
vertically.
It worked flawlessly for about 3 days, then spontaneouslt theradio
went dead again.
I ever so gently tapped the heatsink that this transistor is on, and
once
again everything is fine. I have not lifted the board yet to look at
the solder
underneath. However I'm beginning to think that it is the transistor
itself
that is the problem. Can I find the exact replacement atradioshack?
If I'm going to lift the board, I'm thinking it's probably makes sense
to replace the
device.

  Thanks






Just resolder the transistor. You will see that the solder connections there
have ring cracks from age and heating / cooling over the course of time.
Common problem.

Mark Z.- Hide quoted text -

- Show quoted text -

Hi ,

I decided to lift the board and look at the solder for the device
sanyo 313e.
Before I could do anything the V shaped metal (heatsink?) attached to
the
device just fell off. The plastic screw holding it had just cracked in
half.
There also is a thin piece of plastic between the device and the
heatsink.
I'm assuming that they do want the device to touch the metal.
I could not find a another plastic screw, so I use a metal one with
an
insulating washer. I hope that is ok. Why does the device need to be
insulated from the metal heatsink. Is it strictly pecautionary, in
case
the heatsink comes in contact with something else. Would it be ok
to put some cpu grease between the device and the plastic insulator?
Anyway after all this the solder looked ok, so I did not resolder.
I wonder if my problem all along was that the heatsink
was just hanging on by a thread.
Anyway it seems to work ok. I'll run it for a while with the case
open
as a precaution.

Thanks

 

[[email protected]]

Hi ,

I decided to lift the board and look at the solder for the device
sanyo 313e.
Before I could do anything the V shaped metal (heatsink?) attached to
the
device just fell off. The plastic screw holding it had just cracked
in
half.
There also is a thin piece of plastic between the device and the
heatsink.
I'm assuming that they do want the device to touch the metal.
I could not find a another plastic screw, so I use a metal one with
an
insulating washer. I hope that is ok. Why does the device need to be
insulated from the metal heatsink. Is it strictly pecautionary, in
case
the heatsink comes in contact with something else. Would it be ok
to put some cpu grease between the device and the plastic insulator?
Anyway after all this the solder looked ok, so I did not
resolder.
I wonder if my problem all along was that the heatsink
was just hanging on by a thread.
Anyway it seems to work ok. I'll run it for a while with the case
open
as a precaution.


Thanks

 

[Jamie]

Hi ,

I decided to lift the board and look at the solder for the device
sanyo 313e.
Before I could do anything the V shaped metal (heatsink?) attached to
the
device just fell off. The plastic screw holding it had just cracked in
half.
There also is a thin piece of plastic between the device and the
heatsink.
I'm assuming that they do want the device to touch the metal.
I could not find a another plastic screw, so I use a metal one with
an
insulating washer. I hope that is ok. Why does the device need to be
insulated from the metal heatsink. Is it strictly pecautionary, in
case
the heatsink comes in contact with something else. Would it be ok
to put some cpu grease between the device and the plastic insulator?
Anyway after all this the solder looked ok, so I did not resolder.
I wonder if my problem all along was that the heatsink
was just hanging on by a thread.
Anyway it seems to work ok. I'll run it for a while with the case
open
as a precaution.

Thanks

The metal back plane of the component most likely has connection to one
of the electrical pins which can not be shorted to the case.
this is common.


http://webpages.charter.net/jamie_5"

 

[Mark D. Zacharias]

Hi ,

I decided to lift the board and look at the solder for the device
sanyo 313e.
Before I could do anything the V shaped metal (heatsink?) attached >to
the
device just fell off. The plastic screw holding it had just cracked >in
half.
There also is a thin piece of plastic between the device and the
heatsink.
I'm assuming that they do want the device to touch the metal.
I could not find a another plastic screw, so I use a metal one with <an
insulating washer. I hope that is ok. Why does the device need to >be
insulated from the metal heatsink. Is it strictly pecautionary, in
case
the heatsink comes in contact with something else. Would it be ok
to put some cpu grease between the device and the plastic >insulator?
Anyway after all this the solder looked ok, so I did not resolder.
I wonder if my problem all along was that the heatsink
was just hanging on by a thread.
Anyway it seems to work ok. I'll run it for a while with the case
open

as a precaution.

Thanks

If the solder is really OK, which I doubt. Then the transistor is failing.
On this TO-220 case transistor this most commonly happens from a
base-emitter junction opening up internally.

If you were to look very closely at the solder connections ( I recommend a
magnifying glass) I believe you will see the ring-cracks around the
transistor leads.

In this particular case the heat sink has no other electrical connection,
but you are still going to need another screw and nut. Another mica
insulator and some silicon grease would be good, although as I say, in this
case I think you could dispense with the mica.

Alternatively you could use a newer style TO-220PL plastic case transistor
such as a 2SC4793 which requires no insulator.

It's unfortunate in a way that your skills and experience don't seem to
quite be up to the task. I don't say that as a put-down, but this whole
thing should have been over long ago.

If you decide to replace the transistor, you'll need a source for the part,
and most suppliers have 15.00 to 20.00 minimum orders.

You might consider OEQuotefix to fix your problem with Outlook Express
making messy looking posts. It's a free download.


Mark Z.

 

[[email protected]]

<SNIP>

 >  I decided to lift the board and look at the solder for the device




 >  Anyway it seems to work ok. I'll run it for a while with the case>open

as a precaution.


If the solder is really OK, which I doubt. Then the transistor is failing.
On this TO-220 case transistor this most commonly happens from a
base-emitter junction opening up internally.

If you were to look very closely at the solder connections ( I recommend a
magnifying glass) I believe you will see the ring-cracks around the
transistor leads.

In this particular case the heat sink has no other electrical connection,
but you are still going to need another screw and nut. Another mica
insulator and some silicon grease would be good, although as I say, in this
case I think you could dispense with the mica.

Alternatively you could use a newer style TO-220PL plastic case transistor
such as a 2SC4793 which requires no insulator.

It's unfortunate in a way that your skills and experience don't seem to
quite be up to the task. I don't say that as a put-down, but this whole
thing should have been over long ago.

If you decide to replace the transistor, you'll need a source for the part,
and most suppliers have 15.00 to 20.00 minimum orders.

You might consider OEQuotefix to fix your problem with Outlook Express
making messy looking posts. It's a free download.

Mark Z.- Hide quoted text -

- Show quoted text -

No need to be nasty.
The solder looked ok to me.
The board is very old, so the plan is to proceed cautiously.
I have attached the device properly to the heatsink.
If the problem recurrs, I will reheat the solder joints.
If that does not solve the problem then I will replace the device.
I'm assuming that a 2sd613 will be an adequate replacement, correct?

 

[Mark D. Zacharias]

as a precaution.


If the solder is really OK, which I doubt. Then the transistor is failing.
On this TO-220 case transistor this most commonly happens from a
base-emitter junction opening up internally.

If you were to look very closely at the solder connections ( I recommend a
magnifying glass) I believe you will see the ring-cracks around the
transistor leads.

In this particular case the heat sink has no other electrical connection,
but you are still going to need another screw and nut. Another mica
insulator and some silicon grease would be good, although as I say, in
this
case I think you could dispense with the mica.

Alternatively you could use a newer style TO-220PL plastic case transistor
such as a 2SC4793 which requires no insulator.

It's unfortunate in a way that your skills and experience don't seem to
quite be up to the task. I don't say that as a put-down, but this whole
thing should have been over long ago.

If you decide to replace the transistor, you'll need a source for the
part,
and most suppliers have 15.00 to 20.00 minimum orders.

You might consider OEQuotefix to fix your problem with Outlook Express
making messy looking posts. It's a free download.

Mark Z.- Hide quoted text -

- Show quoted text -

No need to be nasty.
The solder looked ok to me.
The board is very old, so the plan is to proceed cautiously.
I have attached the device properly to the heatsink.
If the problem recurrs, I will reheat the solder joints.
If that does not solve the problem then I will replace the device.
I'm assuming that a 2sd613 will be an adequate replacement, correct?

*****************************
A 2SD 613 would be fine.

I'm not sure why the > marks aren't showing in the quoted sections, I had to
add them manually last time.

I don't feel I was being nasty before, even said so:

I don't say that as a put-down, but this whole
thing should have been over long ago.

I was watching as several other responders were telling you to replace the
transistor and a lot of back-and-forth when as I say this coulda / shoulda
been over with long ago.

mz

 

[[email protected]]

No need to be nasty.
The solder looked ok to me.
The board is very old,  so the plan is to proceed cautiously.
I have attached the device properly to the heatsink.
If the problem recurrs, I will reheat the solder joints.
If that does not solve the problem then I will  replace the device.
I'm assuming that a 2sd613 will be an adequate replacement, correct?

*****************************
A 2SD 613 would be fine.

I'm not sure why the > marks aren't showing in the quoted sections, I had to
add them manually last time.

I don't feel I was being nasty before, even said so:


I was watching as several other responders were telling you to replace the
transistor and a lot of back-and-forth when as I say this coulda / shoulda
been over with long ago.

mz- Hide quoted text -

- Show quoted text -

OK thanks sounds good.
One more question.
In the process of lifting the board to examine underneath,
the plastic tabs that hold the board in place are very brittle.
One broke and the others half broke off. Can I pull these out
from the side that the power supply board is on?
I'm thinking that mayb I can replace these with some
computer mainboard ones that I have lying around?

Thanks

 

[Mark D. Zacharias]

No need to be nasty.
The solder looked ok to me.
The board is very old, so the plan is to proceed cautiously.
I have attached the device properly to the heatsink.
If the problem recurrs, I will reheat the solder joints.
If that does not solve the problem then I will replace the device.
I'm assuming that a 2sd613 will be an adequate replacement, correct?

*****************************
A 2SD 613 would be fine.

I'm not sure why the > marks aren't showing in the quoted sections, I had
to
add them manually last time.

I don't feel I was being nasty before, even said so:


I was watching as several other responders were telling you to replace the
transistor and a lot of back-and-forth when as I say this coulda / shoulda
been over with long ago.

mz- Hide quoted text -

- Show quoted text -

OK thanks sounds good.
One more question.
In the process of lifting the board to examine underneath,
the plastic tabs that hold the board in place are very brittle.
One broke and the others half broke off. Can I pull these out
from the side that the power supply board is on?
I'm thinking that mayb I can replace these with some
computer mainboard ones that I have lying around?

Thanks

Yes, if the area to be soldered can only be accessed by pulling the board
up - it's been a long time since I've worked on a 727. I was thinking the
board could be accessed from underneath.


Mark Z.

 

[dBc]

Greetings TX7123 & others..

Regarding:
"If you decide to replace the transistor, you'll need a source for the
part, and most suppliers have 15.00 to 20.00 minimum orders."

Consider:
http://www.electronix.com/catalog/product_info.php/products_id/3545
http://www.mcmelectronics.com/content/ProductData/Catalog50/section16.pdf
http://www.rcetronics.com/transist.htm
( "No order is too small." )

For the datasheet on a 2SD613:
http://www.littlediode.com/components/product.php?productid=46727&cat=287&page=209
( click on, Click Here, at the page - make sure you have Adobe
Reader )

Incidentally, Mouser does not have a minimum order however, they do
not show stock on a 2SD613. Needless to say shipping has gone way up
for *everyone.*
http://www.mouser.com/

At 1490 pages, Mouser [typically] has what you need. I don't doubt
that they have an equivalent to the 2SD613 in stock. However, with
the above actual transistors, you have alternatives.

Regarding the 2SC4793:
http://www.mouser.com/Search/Refine...&OriginalKeyword=2SC4793&Ntk=Mouser_Wildcards

Cheers,
Mr. Mentor




|
|
| On May 3, 5:19 pm, "Mark D. Zacharias" <[email protected]>
| wrote:
| >Hi ,
|
| <SNIP>
|
| > I decided to lift the board and look at the solder for the device
| >sanyo 313e.
| >Before I could do anything the V shaped metal (heatsink?) attached

to

| >the
| >device just fell off. The plastic screw holding it had just cracked

in

| >half.
| >There also is a thin piece of plastic between the device and the
| >heatsink.
| >I'm assuming that they do want the device to touch the metal.
| >I could not find a another plastic screw, so I use a metal one
with
| <an
| >insulating washer. I hope that is ok. Why does the device need to

be

| >insulated from the metal heatsink. Is it strictly pecautionary, in
| >case
| >the heatsink comes in contact with something else. Would it be ok
| >to put some cpu grease between the device and the plastic

insulator?

| > Anyway after all this the solder looked ok, so I did not
resolder.
| >I wonder if my problem all along was that the heatsink
| >was just hanging on by a thread.
| > Anyway it seems to work ok. I'll run it for a while with the case
| >open
| as a precaution.
|
| >Thanks
|
| If the solder is really OK, which I doubt. Then the transistor is
failing.
| On this TO-220 case transistor this most commonly happens from a
| base-emitter junction opening up internally.
|
| If you were to look very closely at the solder connections ( I
recommend a
| magnifying glass) I believe you will see the ring-cracks around the
| transistor leads.
|
| In this particular case the heat sink has no other electrical
connection,
| but you are still going to need another screw and nut. Another mica
| insulator and some silicon grease would be good, although as I say,
in this
| case I think you could dispense with the mica.
|
| Alternatively you could use a newer style TO-220PL plastic case
transistor
| such as a 2SC4793 which requires no insulator.
|
| It's unfortunate in a way that your skills and experience don't seem
to
| quite be up to the task. I don't say that as a put-down, but this
whole
| thing should have been over long ago.
|
| If you decide to replace the transistor, you'll need a source for
the part,
| and most suppliers have 15.00 to 20.00 minimum orders.
|
| You might consider OEQuotefix to fix your problem with Outlook
Express
| making messy looking posts. It's a free download.
|
|
| Mark Z.
|
|

 

[[email protected]]

Well just when I thought everything was fixed...
The receiver had worked flawlessly for over 3 weeks.
Then suddenly today the radio went dead again.
I took it apart and this time reheated one of the solder
joints on the questionable transistor (d313e).
Anyway everything is back together and working.
Hopefully this will permanently fix the problem.
The plastic tabs that hold the board in place are disintegrating.
Anybody know where I can get similar tabs?
Thnaks.

 

[Jamie]

Well just when I thought everything was fixed...
The receiver had worked flawlessly for over 3 weeks.
Then suddenly today the radio went dead again.
I took it apart and this time reheated one of the solder
joints on the questionable transistor (d313e).
Anyway everything is back together and working.
Hopefully this will permanently fix the problem.
The plastic tabs that hold the board in place are disintegrating.
Anybody know where I can get similar tabs?
Thnaks.

You mean nylon stand offs?
places like Mouser, Digikey etc.. have hard things like that.


--
"I'd rather have a bottle in front of me than a frontal lobotomy"

"Daily Thought:

SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT
THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.
http://webpages.charter.net/jamie_5"