Erukian Posted December 4, 2004 Share Posted December 4, 2004 I have a Yamaha CA-800 Integrated amp, which is really good for my ears, made 1974 .. 30 years old The issue is that when first turn on the amp it's fine, but after 5-15 minutes it does a crackle--POP only on the right channel. Once it starts it'll do it randomly, usually about 1 minute apart though. Since it doesnt do the crackle-pop initially i think it's a heat problem, the amp has a Class A and a class A-B switch, even though class A makes a lot more heat when switched to either it doesnt make the crackle-pop happen. The sound only lasts a second, crackle..pop. I can watch my right mid-woofer on the RB-25 go in and out pretty far when it pops, it's scary. God.. 1812 overture sounds SOO awesome (especially the trumpets) on this Yamaha Amp over my Harman Kardon (vintage 1978). I HAVE to get this amp working again, if i can repair it for under 100 then i'll do it. If not then i might as well buy a working good classic amp off ebay. What part of the amp would cause this corruption of the sound? Thanks for any guesses / suggestions you guys got in advance. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted December 4, 2004 Share Posted December 4, 2004 Hi, Erukian: To avoid possibly damaging other components down stream (loudspeakers), I would suggest taking the amp out of survice until the problem is found and corrected. I have found loud pops such as you describe to be sometimes associated with AC power supply connections -- poorly soldered power transformer or rectifier connections, and so forth. These are generally easy and inexpensive to repair so long as they are OUTSIDE the windings of the transformer, itself. If the opposite is the case, things get both more complicated and lots more expensive. If you don't have experience with this sort of thing, find an electronics technician in your area who could help you out. Good luck, some of those vintage amps from the 70s (I have three!) are really pretty good sounding! Erik Quote Link to comment Share on other sites More sharing options...
djk Posted December 4, 2004 Share Posted December 4, 2004 Replace ALL of the 2SC1345E transistors in this unit. They develop pop corn noise. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted December 4, 2004 Share Posted December 4, 2004 With all due respect, I think it might be prudent to perform some preliminary troubleshooting on the amplifier, preferably done by a qualified or experienced technician, before anything is replaced, thown out, new parts purchased, etc. You may have hit the nail right on the head, but I have to submit that there is the possibility that some other aspects of the unit might be causing the problem. Erik Quote Link to comment Share on other sites More sharing options...
Erukian Posted December 4, 2004 Author Share Posted December 4, 2004 ---------------- On 12/4/2004 7:28:43 AM djk wrote: Replace ALL of the 2SC1345E transistors in this unit. They develop pop corn noise. ---------------- Where have you heard this? Do the transistors do this over time in Yamaha amps? Do I replace it with the same transistors? like buy these? http://mcm.newark.com/NewarkWebCommerce/mcm/en_US/endecaSearch/partDetail.jsp?SKU=2SC1345&N=4 Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted December 4, 2004 Share Posted December 4, 2004 wow, $0.13 apiece. Sounds like something that could go bad. Quote Link to comment Share on other sites More sharing options...
djk Posted December 4, 2004 Share Posted December 4, 2004 I was an authorized Yamaha service center when this amp was new. While it seems like I replaced millions of these transistors, it was probably only thousands. After 30 years it could be another plastic transistor failing too. If it was making noise constantly you could find it with freeze mist. It is easier to just replace them all, they cost very little. Quote Link to comment Share on other sites More sharing options...
Klipsch RF7 Posted December 4, 2004 Share Posted December 4, 2004 I used to know a guy who had a vintage Marantz 2250 Solid state reciever from the 70's, his would do the same exact thing. It would snap and pop out of the Left channel every so often. We cracked it open and used canned air and blew all the dirt and dust off the innards and got basically everything very clean. We put put the cover back on and plugged her in and never heard a pop ever since, you might want to try that as a first step Quote Link to comment Share on other sites More sharing options...
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