drsickstrings 3 Posted September 17, 2016 Author Share Posted September 17, 2016 Welcome to the site! Here is my thread for a M500t recap....... http://thecarversite.com/yetanotherforum/default.aspx?g=posts&t=25877 Dadvw Thank you for the thread. I am thinking of recapping mine. Some leakage in mine. There isn't a ton of work to do. Just curious....do you have any pictures of the bottom of the board prior to the rebuild? Mine has handful of small caps and resistors soldered to the bottom. I'm not sure if they are supposed to be there. Link to comment Share on other sites More sharing options...
drsickstrings 3 Posted September 17, 2016 Author Share Posted September 17, 2016 Ok....I got it fixed. Nothing wrong with the Preamp. I plugged it into My HK 870 amp. It sounded great. I knew the amp was the problem. One channel was a lot louder than the other but sounded like a transistor radio. I got the shop manual and started doing some tests. Looking for 6mv at the test points. One channel was around 3mv and the other channel was around 77mv or some ridiculous number. Got them balanced around 6.6mv and plugged it in. THe amp sounds great. I also noticed that I can calibrate the meters. I don't have any equipment to give me a signal at 100w. I ordered new terminals, and I still plan on recapping it...some of the big caps have leaked a bit. I am also replacing the lamps with blue led bulbs. Does anybody know any way to calibrate them reasonably well without a scope and signal generator? Link to comment Share on other sites More sharing options...
B-Man 4,763 Posted September 18, 2016 Share Posted September 18, 2016 I doubt the caps have leaked - there is a glue present on the caps in most Carver amps that was used to hold the caps to the board during the wave soldering process. If the caps were in that bad shape, I would bet the amp would sound like it had issues. I know of no way to calibrate meters without proper test gear. To properly calibrate something requires using test gear with operating specs that are better than the gear you are trying to calibrate. Link to comment Share on other sites More sharing options...
Dadvw 2,803 Posted September 18, 2016 Share Posted September 18, 2016 Ok....I got it fixed. Nothing wrong with the Preamp. I plugged it into My HK 870 amp. It sounded great. I knew the amp was the problem. One channel was a lot louder than the other but sounded like a transistor radio. I got the shop manual and started doing some tests. Looking for 6mv at the test points. One channel was around 3mv and the other channel was around 77mv or some ridiculous number. Got them balanced around 6.6mv and plugged it in. THe amp sounds great. I also noticed that I can calibrate the meters. I don't have any equipment to give me a signal at 100w. I ordered new terminals, and I still plan on recapping it...some of the big caps have leaked a bit. I am also replacing the lamps with blue led bulbs. Does anybody know any way to calibrate them reasonably well without a scope and signal generator? Great to hear you got it fixed! I think Dr. Z uses his phone and an RCA headphone jack to dual RCA with some tone generation software. You set the freq for 1KHz and adjust the meters for 100W indication. Correct me if I am wrong Dr. Z......grin Link to comment Share on other sites More sharing options...
zumbini 6,138 Posted September 18, 2016 Share Posted September 18, 2016 Ok....I got it fixed. Nothing wrong with the Preamp. I plugged it into My HK 870 amp. It sounded great. I knew the amp was the problem. One channel was a lot louder than the other but sounded like a transistor radio. I got the shop manual and started doing some tests. Looking for 6mv at the test points. One channel was around 3mv and the other channel was around 77mv or some ridiculous number. Got them balanced around 6.6mv and plugged it in. THe amp sounds great. I also noticed that I can calibrate the meters. I don't have any equipment to give me a signal at 100w. I ordered new terminals, and I still plan on recapping it...some of the big caps have leaked a bit. I am also replacing the lamps with blue led bulbs. Does anybody know any way to calibrate them reasonably well without a scope and signal generator? Great to hear you got it fixed! I think Dr. Z uses his phone and an RCA headphone jack to dual RCA with some tone generation software. You set the freq for 1KHz and adjust the meters for 100W indication. Correct me if I am wrong Dr. Z......grin A cell phone with a test tone app is just one of many ways to generate the 1kHz test tone. When Zack is home I use Audio Test Bench software on his laptop to generate the 1kHz tone. More recently I used an mp3 player loaded with track 4 of the Carver Sonic Holography test disc. Irregardless, I run the test tones into the preamp aux inputs, and adjust gain to provide a 1v output. For an M-500t I adjust the meter calibration pots (SRV601/602) until the meters read 100w. Link to comment Share on other sites More sharing options...
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