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
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.
__
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
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.