Rotel RA-810a issues

[audio amateur]

I bought this 20 year old or so integrated amp off ebay uk in order to replace the Trends TA-10.1 that I fried (Trends is awaiting potential repair).
When I power the Rotel on or off, the speakers pop and the woofers move about half an inch. It's especially bad when turning off, and I notice it happens a couple seconds after I've press the button (at which point the sound also cuts off). I know energy is stored and has to run out after the unit is shut off, hence the delay for the sound to stop (which I believe is normal).
My question is why the pop and is there a connection between the slow power off and the pop?

Also, I've read that the 'output ic's' on this amp are notorious for burning out, what exactly are these and how would I go about replacing them when the time comes?

[poppachubby]

Sounds like the time has arrived. Firstly, are you able/confident to open it up and do some work? Secondly, have you opened it to take a look?

It sounds like a connection or possibly the AC ground. I'm not familiar with this unit, and I'm not sure what you mean by "burn out". It could just be the caps or resistors in the output ciruitry have met their end. This is not unusual for an aged unit.

I have to go out but write back and I'll hit you back later...

http://i6.ebayimg.com/03/i/001/41/64/5bf2_12.JPG

If you really value this item, I would try to get it to an experienced tech. If you got a good deal from Ebay, then consider the cost of a repair as added value to your purchase price. It is definitely fixable...

[audio amateur]

I got it pretty cheap so as a 'temporary' solution it's working very nicely. I've become attached to it, so if I can give it longer life, why not! I hate to see stuff die and if it's fixable I want to give it the attention it deserves.

I need to clarify that currently nothing is wrong with the unit, aside my poor lil' 686's woofers being stretch at power up and power down. This is why I ask if there's anything I should be looking at that may be causing this.

I've little experience in electrics but I have done soldering in the past and know a little about components. If I'm going to learn, it might as well be on this unit.
I have opened it and dusted the interior. There doesn't seem to be anything wrong internally.
As for the burning out, i don't know what that means either. Perhaps someome here does

[Jim Eck]

Sounds like it might be DC coupled, my, Marantz 2235B is DC coupled, did your amp always do this or is it a new development?

Do a search on DC offest, and do a check, you will need a multimeter, in your investigation you will learn about being DC coupled or not.

Jim

[audio amateur]

I'm pretty sure it's done it since I bought it, but bear in mind it is 20 years old approx. and I've only have it for a few months. Could have developed when the previous owner had it.

[harley .guy07]

back before soft start features were added to amps and receiver/int amps they would do this when powering up and shuting down. the power supply inside of amps is at full power when starting up so if there is no mute in the signal it will cause this. Newer amps have a soft start feature added to them which is basically a mute circuit that will mute the audio output for a couple of seconds after you push the power button and allows the signal to unmute after the power supply settles down to an idle current. This has been around a while so I am supprised that your Rotel does not have this. Now it might be that the control circuit for the soft start feature has quit working which would cause your problem. the only way to find out is to study up on your model to see if it came out with the soft start feature or not and if it did then the next step is to figure out if it can and where to get it fixed and most importantly if it is worth the money to fix. now when you shut the amp off the woofer movement is most likely your stiffining capacitors bleeding off their current and there are a lot of amps out there that do it I know My Adcom 545II does it a little bit but not bad enough to hurt anything. I remember my dad had a technics int amp back in the 70's that sounded like you blew the speakers every time you turned it on.

[harley .guy07]

I'm pretty sure it's done it since I bought it, but bear in mind it is 20 years old approx. and I've only have it for a few months. Could have developed when the previous owner had it.

If its 20 years old or so then it was made in the late 80's or early 90's and soft start was almost a standard part of every receiver/int amp or power amp so this would make me believe that the soft start circuit in your Rotel is not working and it probably did have it when it was new. But I might be wrong

[Jim Eck]

You might want to give this a read.

http://www.neufeld.newton.ks.us/electronics/?p=147

Jim

[harley .guy07]

You might want to give this a read.

http://www.neufeld.newton.ks.us/electronics/?p=147

Jim

Makes sense. this could be a problem as well especially if this components did not have the soft start in it. then all of this would shoot directly to the speakers of startup and shutdown.