Rotel RSP-985 problem

[wgmontgomery]

Hi...I am new to this forum and hope that someone here can help. I lost my "old" system to my ex and am now re-building from stratch and on a tight budget.

I picked-up an old RSP-985 (DD, DTS, THX...) pre/pro that sounds great...except for an ever present hum. I have tried to track down any ground problems, and that doesn't seem to be the case. It isn't the amp; I have done a lot of trouble shooting and it HAS to be the Rotel. Is this a common problem and is there an easy solution?

BTW-all of my gear is plugged into a massive APC, and I have a plasma TV. I have also tried different interconnects. I am grateful for any help anyone can offer, thanks!

[madmac]

could be the Plasma TV causing interference. You could try moving the amp away from it?. You have to change each interconnect one by one (Including speaker wires) to be sure that it is not a wiring problem. Make sure you're power receptacles are all grounded. Are you using a sub?. I've gotten hum from subs that had bad wiring before. Also, blow compressed air into all you're connect ports on your equipement.

[wgmontgomery]

I am using a sub, but I've tried two different ones. One was passive, and I still had the same problem. The APC shows that the ground is fine. The hum is present even with the plasma off; I know that it's still drawing current when off, but I would think that it wouldn't generate interference while off.

I haven't tried compressed air. I did, however, go from RCA interconnects to a shielded (Belkin Pro) DB25 without a change. I am also looking into the internet connection to the BD player as it's a wired conection. It doesn't seem to be the cause, either.

I wonder if anyone else has had this same problem with the Rotel RSP-985? It's an old piece, but it still sounds pretty good and matches my budget. It's a start, anyway.

Thanks for all of your help; I'll try the compressed air. Moving everything away from the TV is a last resort due to space and cable length. Thanks again!

[Glen B]

Do you have CATV connected to your system ? The cable connection can sometimes cause hum problems. The solution is to insert an isolating balun between the cable and your cable box or TV. If you have digital cable, be sure to get an isolator that works with digital signals -- not all do -- or you will have problems.

http://www.hefnerlabs.com/main/cgli-2

[wgmontgomery]

Yes... I have cable conected to the TV. My cable, phone and internet all come in on the same cable; cable AND internet go to the system. I'll try unhooking cable and internet and see what happens. If one of them is causing the problem then I would think that disconnecting them would resolve the problem...or at least point me in the right direction. Thanks...I'll try it and post results. Thanks again!

[madmac]

I agree. ALL connections to the system must be checked, one by one. It is not necessary to change the connections, only to remove them, then turn on the system and see if the hum is gone with that one connection removed. The chances of there being 2 or more bad wires is very slim. At the end of the day, if all your connections are good then I would have to suspect the Rotel. Open it up in that case and give it a good blast of compressed air....inside and out.

[wgmontgomery]

It looks like I'm going to have to try to open the hood anf see what's up. Is there a way to reset the microprocessors? I remember that my Lexicon had a reset feature (bypass and power at the same time...something like that) that ALWAYS fixed problems. I'd have to re-program everything, but it was worth it. There's nothing in the manual about it...

[srb]

Is there a way to reset the microprocessors? I remember that my Lexicon had a reset feature (bypass and power at the same time...something like that) that ALWAYS fixed problems. I'd have to re-program everything, but it was worth it. There's nothing in the manual about it...

You can do a factory reset from the ON SCREEN MENU.

SYSTEM SETUP > FACTORY DEFAULT (Page 23)

Steve

[petewill]

I'd say disconnect everything except for the preamp, power amp(s) and speakers. Still have a hum? Then disconnect the preamp and see if you have hum with amp(s) and speakers only.

[wgmontgomery]

Power and and speakers=no hum. Everyhting off EXCEPT amp, speakers, Rotel= hum, so the hum is generated by the Rotel. I will try plugging other units into another outlet, but I figured that the APC should take care of that problem...who knows. I'll try anything at this point.

I should actually have some time this weekend to devote fully to fixing this problem. I saw the reset in the menu, but I wondered if it reset the pre/pro to factory defaults (as described in the manual) or was an actual reset.

I want to say thanks to everyone....thanks! *-)

[petewill]

I sent you a private message sent via email, wgmontgomery.

[wgmontgomery]

Thanks petewill; I got your message and have responded. I have tried everything short of popping open the cover and blowing it out with compressed air; I will go pick up a can of air (lol) and try that...the hum is driving me crazy.

A few things that I have noticed about the Rotel vs. "my" Lexicon MC-1. On DD and DTS material, they are very close. On pro-logic the Lexicon is MUCH better. I must admit that it's not a fair comparison as I have also went from B&W Nat. speakers to Kef 2005.2 with a NHT passive sub and Kef PSW2500. ONE of the B&W Nat. 802s cost more than what I have in my whole system right now. (sigh) I have to start somewhere.

Well...I plan to spend the day tracking down the hum. Thanks to all; if I figure it out I'll be sure to post the solution as it may help someone else. I did the reset in the menu, but it did not help.

[wgmontgomery]

I have spent all weekend attempting to track down the source of this problem. I have tried everything and have found no solution. Perhaps I have a defective unit? My fiscal situation behing what it is perhaps I'll have to live with it for now. IF I find the solution I'll be sure to post it in case someoen else has the same problem. Thanks to all!

[Rotel4Life]

Did you recently (Dec 2012) sell this 985 on eBay? If you did.... I bought it! lol. The hum in mine isn't too bad, but if it's on w/o a source there is a definite hum. Can't notice when sound is coming thru so I can live with it.

[Rotel4Life]

Just fixed my hum. Replaced the DB25 with RCAs. Tried 2 different db25 cables, both had hum. DB25 worked great (no hum) with a rtc965. Hum with everything unplugged (except rsp985 and amp). So 100% the problem is in the db25 output of my 985. If you're using RCAs I guess that ain't your fix, but it was mine..

[Vanhalino]

Hi everyone, guys!

I am also new to the forum, and I have resumed this topic because I am in great difficulty with the Rotel RSP-985.

Suddenly, I found some slowdowns in the response of the selection keys of the various audio output channels coupled with a more serious problem that is definitely related to the first one: no sound source from any channel is heard anymore.

I have already sent the unit to the assistance, but the problem was initially attributed to capacitors that needed to be discharged by a disconnection of the power cable for 48 hours.
Actually, the amplifier has resumed working properly.

After a year or so, the same problem reappeared, but this time the procedure did not have any positive effect.

Now I'm with an aesthetically perfect device, but unfortunately I can't use it anymore.
I wanted to ask you if you have any solution, or if you have already heard of this problem in relation to the Rotel RSP-985.

I hope there is some of you who can give me some precious suggestions, because I'm really desperate: I would not have to sell it, and above all sell it as "not working" at a ridiculous price.

Thank you

[wkhanna]

realistically, the cost & effort for repair may not justify the value of this unit.....

a used replacement may be the best alternative....