Steve Snow 12 Posted July 29, 2023 Share Posted July 29, 2023 Hello All, I have owned a Sunfire HRS-8 Sub for about 4 years. I was so impressed with it's performance that when a Sunfire True Subwoofer MKIV came up for sale on the Goodwill auction site I had to take a chance on it. Unfortunately when I plugged it in it has a very loud hum. After spending some time searching the internet for repair help I came across this site. I already have several of the electrolytic caps on order. But I have not had much luck finding a schematic for this beast. I would very much appreciate any help from anyone that has gone down this road before. 9 1 Link to comment Share on other sites More sharing options...
Sk1Bum 9,888 Posted July 29, 2023 Share Posted July 29, 2023 Hello Steve, and welcome to thecarversite.com. We're glad you're hear. There is a lot of information here, much technical know how, and a pretty good bunch of folks that are happy to help. I have no experience with Sunfire subs, but hopefully someone here that does will chime in. There are some threads regarding Sunfire sub repair, so maybe this link will help: https://thecarversite.com/search/?q="sunfire subs"&quick=1&updated_after=any&sortby=relevancy Once you get to Novice status, please consider uploading some pics of your gear in the Members Systems area. We all like pics of all kinds of audio gear. In the meantime, kick your shoes off, turn up the music, and welcome aboard. 3 Link to comment Share on other sites More sharing options...
itchitch 3,997 Posted July 30, 2023 Share Posted July 30, 2023 Welcome to the site! There are few members that have dug deep in to the Sunfire subs. Keep searching the site. Be patient for someone to respond... it's summer 2 Link to comment Share on other sites More sharing options...
Receiver2000 2,465 Posted July 30, 2023 Share Posted July 30, 2023 Hi Steve Welcome to the site!!!! Great to have you. 2 Link to comment Share on other sites More sharing options...
wrf 3,829 Posted July 30, 2023 Share Posted July 30, 2023 Unfortunately we don't have a schematic for the TS MK IV. We have them for the TS EQ and the TS Junior, but no MkIV. Here's a thread that offers several tips. In general, the TS MK "X" subs are full of bad capacitors. Problems with hum, auto on/off, strange pops and clicks are common. A good policy is to replace them all except the two big ones mounted to the front panel. If you want to cherry pick, a good place to start are the low voltage power supply caps in the corner of the bottom board, mounted next to all the hot resistors. There are also four smaller caps clustered together on the preamp board, that are among the first to go. BE CAREFUL. The big high voltage supply caps hold a charge for a VERY long time. Best to check them and discharge them before touching anything. They can and will deliver a serious shock that can blow the tips off screw drivers, burn body parts and leave you with numb hands or fingers. Here's a post that may help. There are other, look around. 7 Link to comment Share on other sites More sharing options...
Ar9Jim 6,056 Posted July 30, 2023 Share Posted July 30, 2023 Hi Steve, Welcome to TCS.. Enjoy! 3 Link to comment Share on other sites More sharing options...
Community Admin AndrewJohn 8,184 Posted July 30, 2023 Community Admin Share Posted July 30, 2023 Welcome, @Steve Snow, glad you found us. That's a good sub - and worth fixing, if it is not catastrophically damaged. Hang around a while, and add some content. We love pictures! 3 Link to comment Share on other sites More sharing options...
Rob 4,306 Posted July 30, 2023 Share Posted July 30, 2023 Hello and welcome to the site. I had a MK4 Sunfire that was fine in my house but when plugged into a friend of mine he had a bad hum. Try different rooms on different circuits and see if it makes a difference. He eventually found a circuit that was quiet. 3 Link to comment Share on other sites More sharing options...
Kurt 1,390 Posted July 30, 2023 Share Posted July 30, 2023 Welcome to the Carver Site! 1 1 Link to comment Share on other sites More sharing options...
Zenith4me 1,386 Posted July 31, 2023 Share Posted July 31, 2023 Welcome to The Carver Site! 1 1 Link to comment Share on other sites More sharing options...
Cring08 149 Posted August 1, 2023 Share Posted August 1, 2023 Welcome! 1 1 Link to comment Share on other sites More sharing options...
Steve Snow 12 Posted September 15, 2023 Author Share Posted September 15, 2023 Thanks for all of the welcomes and repair tips. Sorry I have been busy with other things haven't had a chance to check back on this board.(One of them being repairing an old Franklin Ace computer) Now I can get back to working on the sub. So far I have only replaced the two 2200 uf capacitors. That seems to have gotten rid of the hum. But now when I try to drive it with an audio signal I only get loud pops every now and then. I'm going to read through the tips that wrf posted. The sub appears to be in good physical condition and I would say I am the first one to have opened it since it was new. Like wrf suggested, I think I'll start replacing all of the low voltage caps. 3 Link to comment Share on other sites More sharing options...
halfbaked 167 Posted September 15, 2023 Share Posted September 15, 2023 Welcome, you came to a great place for Carver gear. Definitely replace those old caps and good luck with your Carver gear. 2 Link to comment Share on other sites More sharing options...
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