Something Stinks

I've had my McIntosh MCD7007 for around 20 years now. Although it idled for many years I used it often for the first 3 years or so and recently for about 2-1/2 years. It has always worked and performed flawlessly until now. I was curious what a DAC would do for the performance so I just picked up a used Meridian 563 DAC and within a half hour I smelt a burt odor, like a fried circuit board or transformer smell. It seems to be coming from my CD player. Everything still works and sounds good but something is going on. The digital output on my CD player has never been used until now.
Any thoughts ?
It is possible to fry a capacitor or other circuit and the unit will still work. It won't operate as it is intended by spec, but it can still operate. Problem is, now you face the possibility of something more catastrophic and god forbid, a fire. When electronics burn out at work, that unit does not operate until we've found and fixed whatever the problem was. You should do the same. I'd take it to an electronics store and have it looked over. That is, before you lose your entire investment. It may not be thay severe, but better safe than sorry.
Yes, I understand that I should not use it, and I have not since the smell occured.

Well I just opened the top cover of my CD player and isolated where the “burnt smell” is coming from. There are small heat fins (maybe 3”x4”) with some internal electronics right next to the “Digital Output” connector.The odor is there. Nothing appears to look “burnt”.
Any MCD7007 owners out there know what this heat sink is for? Is it possible this heat sink is in an isolated circuit with the digital output connector and the fact that this connection just got used for the first time in 20 years cause this odor?