Bought it cheap because of this noise. Right channel only. When
cold, noise is infrequent and as it warms up gets to be an
intermittent scratching with occasional louder pops. Anyone with any
experience on this unit or someone who can offer an idea as to the
culprit? It is beyond the balance control as the noise is unaffected
by it's use. What's the most likely component to be doing this? Any
suggestions appreciated. Thanks!

powerdoc wrote in message
...
Bought it cheap because of this noise. Right channel only. When
cold, noise is infrequent and as it warms up gets to be an
intermittent scratching with occasional louder pops. Anyone with any
experience on this unit or someone who can offer an idea as to the
culprit? It is beyond the balance control as the noise is unaffected
by it's use. What's the most likely component to be doing this? Any
suggestions appreciated. Thanks!


electrolytic


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

"N_Cook" wrote in message
...
powerdoc wrote in message
...
Bought it cheap because of this noise. Right channel only. When
cold, noise is infrequent and as it warms up gets to be an
intermittent scratching with occasional louder pops. Anyone with any
experience on this unit or someone who can offer an idea as to the
culprit? It is beyond the balance control as the noise is unaffected
by it's use. What's the most likely component to be doing this? Any
suggestions appreciated. Thanks!


electrolytic



Possibly. I'm leaning more towards bad solder connections or a bad
differential transistor pair.

Mark Z.

I have had bad electrolytic capacitors and sometimes semiconductor
type devices cause noise. With a scope you can trace through the audio
signal path and determine where the noise is being generated.
Sometimes finding intermittant noise problems can be tricky. An
experienced tech should be able to fix this for you.

Jerry G.

__

On Jan 29, 8:49*pm, powerdoc wrote:
Bought it cheap because of this noise. *Right channel only. *When
cold, noise is infrequent and as it warms up gets *to be an
intermittent scratching with occasional louder pops. *Anyone with any
experience on this unit or someone who can offer an idea as to the
culprit? *It is beyond the balance control as the noise is unaffected
by it's use. *What's the most likely component to be doing this? *Any
suggestions appreciated. *Thanks!

powerdoc wrote:
Bought it cheap because of this noise. Right channel only. When
cold, noise is infrequent and as it warms up gets to be an
intermittent scratching with occasional louder pops. Anyone with any
experience on this unit or someone who can offer an idea as to the
culprit? It is beyond the balance control as the noise is unaffected
by it's use. What's the most likely component to be doing this? Any
suggestions appreciated. Thanks!


Hello,

Below is a reply I sent to someone else a few weeks ago. While the
first paragraph does not apply to your complaint, the second one does.
These units should have at least 4 inches of open air above them, as
they tend to run hot.

Regards,
Tim Schwartz
Bristol Electronics



This unit was a 'customized' (for Carver) version of Marantz SR-92
receiver. Carver issued a bulletin suggesting changing R902 in the
power supply to a 47 ohm 2W flame proof resistor, and at the same time
change the 'hologram relay' to their part number LY20240400, what ever
that is. I would at least find R902 and make sure that it is not open.

These amps also run very hot and sometimes the small driver transistors
in the front amps need to be resoldered and/or replaced. As I recall,
look at Q701 and 703 in the left channel, and Q702 and 704 in the right.
Q701 and 702 are 2SA1145, and Q703 and 704 are 2SC2705. If the area of
the PC board looks cooked, you might want to replace them. I'd check
them with an ohm meter first to see if they are still functional. The
transistors can be ordered from many suppliers, among them (in the US)
MCM Electronics (www.mcmelectronics.com) . You should check over the
soldering of that area of the PC board while you are there.