[KA6UUP]

I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?
Thanks,
Chuck

[Eeyore]

KA6UUP wrote:

I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?

I don't know how old that is but capacitors have shrunk a lot over the years as
the technology to make them has improved.

One of your first concerns will therfore be to make sure the new parts will
physically fit properly.

I wouldn't fret over the brand. 8000 uF is likely to be hard to find (these days
the preferred value is more likely to be 8200uF btw). I'd suggest 10,000 uF. The
value is not that critical.

Graham

[dizzy]

Eeyore wrote:

KA6UUP wrote:

I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?

I don't know how old that is but capacitors have shrunk a lot over the years as
the technology to make them has improved.

One of your first concerns will therfore be to make sure the new parts will
physically fit properly.

I wouldn't fret over the brand. 8000 uF is likely to be hard to find (these days
the preferred value is more likely to be 8200uF btw). I'd suggest 10,000 uF. The
value is not that critical.

digi-key.com is where I get my parts.

[Mark D. Zacharias[_2_]]

"KA6UUP" wrote in message
et...
I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?
Thanks,
Chuck

If they're not badly leaking, open circuit or shorted, they probably don't
need replacing.

Are you having a particular problem with this receiver?

Mark Z.

[KA6UUP]

Mark D. Zacharias wrote:
"KA6UUP" wrote in message
et...
I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?
Thanks,
Chuck

If they're not badly leaking, open circuit or shorted, they probably don't
need replacing.

Are you having a particular problem with this receiver?

Mark Z.


Yes,
Constant hum under all condx.

[Eeyore]

KA6UUP wrote:

Mark D. Zacharias wrote:
"KA6UUP" wrote in message

I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?

If they're not badly leaking, open circuit or shorted, they probably don't
need replacing.

Are you having a particular problem with this receiver?

Yes,
Constant hum under all condx.

Might not be the main PSU caps. In fact I'd go as far as saying likely NOT those
at all unless you're very unlucky. Typically the main PSU caps are the most
generously rated with the best service life.

Possibly the ones filtering power to the preamp stages are to blame.

You need to understand that old equipment may have electrolytic caps that have
'dried out' and lost their capacitance. The small ones are no less likely to do
this than the big ones.

If you had an oscilloscope or microvoltmeter, it would be very simple to find
out.

Graham

[Mark D. Zacharias[_2_]]

"Eeyore" wrote in message
...


KA6UUP wrote:

Mark D. Zacharias wrote:
"KA6UUP" wrote in message

I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt
Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?

If they're not badly leaking, open circuit or shorted, they probably
don't
need replacing.

Are you having a particular problem with this receiver?

Yes,
Constant hum under all condx.

Might not be the main PSU caps. In fact I'd go as far as saying likely NOT
those
at all unless you're very unlucky. Typically the main PSU caps are the
most
generously rated with the best service life.

Possibly the ones filtering power to the preamp stages are to blame.

You need to understand that old equipment may have electrolytic caps that
have
'dried out' and lost their capacitance. The small ones are no less likely
to do
this than the big ones.

If you had an oscilloscope or microvoltmeter, it would be very simple to
find
out.

Graham



Or maybe a ground loop...

mz

[AZ Nomad]

On Thu, 08 Nov 2007 00:39:43 GMT, KA6UUP wrote:
Constant hum under all condx.

How about with no inputs connected?

[Eeyore]

"Mark D. Zacharias" wrote:

Or maybe a ground loop...

Irrelevant in this context.

Graham

[KA6UUP]

AZ Nomad wrote:
On Thu, 08 Nov 2007 00:39:43 GMT, KA6UUP wrote:
Constant hum under all condx.

How about with no inputs connected?
I have checked all electrolytics with a cap tester. The only ones which
failed the test were the two 800 mike 50v caps.
NO inputs just am and fm.

[KA6UUP]

Eeyore wrote:

KA6UUP wrote:

Mark D. Zacharias wrote:
"KA6UUP" wrote in message

I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?
If they're not badly leaking, open circuit or shorted, they probably don't
need replacing.

Are you having a particular problem with this receiver?
Yes,
Constant hum under all condx.

Might not be the main PSU caps. In fact I'd go as far as saying likely NOT those
at all unless you're very unlucky. Typically the main PSU caps are the most
generously rated with the best service life.

Possibly the ones filtering power to the preamp stages are to blame.

You need to understand that old equipment may have electrolytic caps that have
'dried out' and lost their capacitance. The small ones are no less likely to do
this than the big ones.

If you had an oscilloscope or microvoltmeter, it would be very simple to find
out.

Graham

I am using a O'scope. There is 60 cycle om all the boards.

[KA6UUP]

KA6UUP wrote:
AZ Nomad wrote:
On Thu, 08 Nov 2007 00:39:43 GMT, KA6UUP wrote:
Constant hum under all condx.

How about with no inputs connected?
I have checked all electrolytics with a cap tester. The only ones which
failed the test were the two 800 mike 50v caps.
NO inputs just am and fm.
OOPS. make that 8000 mikes

[Eeyore]

KA6UUP wrote:

Eeyore wrote:
KA6UUP wrote
Mark D. Zacharias wrote:
"KA6UUP" wrote in message

I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?
If they're not badly leaking, open circuit or shorted, they probably don't
need replacing.

Are you having a particular problem with this receiver?
Yes,
Constant hum under all condx.

Might not be the main PSU caps. In fact I'd go as far as saying likely NOT those
at all unless you're very unlucky. Typically the main PSU caps are the most
generously rated with the best service life.

Possibly the ones filtering power to the preamp stages are to blame.

You need to understand that old equipment may have electrolytic caps that have
'dried out' and lost their capacitance. The small ones are no less likely to do
this than the big ones.

If you had an oscilloscope or microvoltmeter, it would be very simple to find
out.

I am using a O'scope. There is 60 cycle om all the boards.

That suggests only that your test method is wrong, or you don't know how to
meaningfully interpret the readings.

I'm sorry, but I'm inclined to think you are operating outside your level of
competence.

If you can persuade me otherwise, we may get somewhere.

Graham

[KA6UUP]

New caps installed and it is now working perfectly.
Thanks to all who helped.
Chuck


Eeyore wrote:

KA6UUP wrote:

Eeyore wrote:
KA6UUP wrote
Mark D. Zacharias wrote:
"KA6UUP" wrote in message

I have a Pioneer SX-780 rx and need to replace the 8000 mike 50 volt Caps.
The originals are Elna.
I only need two.
Can anyone recommend a good source who does small quantity orders?
If they're not badly leaking, open circuit or shorted, they probably don't
need replacing.

Are you having a particular problem with this receiver?
Yes,
Constant hum under all condx.
Might not be the main PSU caps. In fact I'd go as far as saying likely NOT those
at all unless you're very unlucky. Typically the main PSU caps are the most
generously rated with the best service life.

Possibly the ones filtering power to the preamp stages are to blame.

You need to understand that old equipment may have electrolytic caps that have
'dried out' and lost their capacitance. The small ones are no less likely to do
this than the big ones.

If you had an oscilloscope or microvoltmeter, it would be very simple to find
out.
I am using a O'scope. There is 60 cycle om all the boards.

That suggests only that your test method is wrong, or you don't know how to
meaningfully interpret the readings.

I'm sorry, but I'm inclined to think you are operating outside your level of
competence.

If you can persuade me otherwise, we may get somewhere.

Graham