Microcassette M-450 Will Not Play Back Cannot Hear Anything

Was working fine. I placed the Sony Microcassette Recorder M-450 on the entertainment wooden holder that houses our tv to record a VHS video onto the Sony tape. I checked it and it appeared to play fine. Now, several months later I tried to play tapes and cannot hear anything other than an occasional noise when I start it. I'm wondering whether I accidentally contaminated it by placing it too close to another source (TV)Question: can I still use the tapes that were so contaminated, or will I need to discard them?Has this likely damaged the microcasette recorder itself, or only ruined the tapes?Can this be fixed? Would appreciate any help. My microcassette recorder still appears to work but no sound. I have not tried with brand new unsused tapes yet because I dont have any. Will microcassette recorder likely work OK with brand new tapes, or is a problem that could have affected the microcassette recorder itself? Are there any other possibilites? I have never cleaned the inside of this unit and have had it for year. Could the problem be that? or other? Microcassette was working fine a few months ago. Haven't used it. Now, appears to work but no playback sound. Also unable to record my voice over the tapes. The tapes themselves could be the problem but I'm concerned I may have inadvertently damaged the microcassette player by placing it too close to the TV and VCR (there are other things which wre turned off that are also within the same entertainment unit such as Playstation 3 and 4. The TV was on and the VCR on to attempt to record a VCR recording playing on the TV onto the microcassette recorder. I checked all microsette tapes and they were fine immediately after recording onto them. That was about 6 monrhs ago. Now I went to play them and there is no sound at all but I can hear the tape attempting to make a sound at the very beginning. It's not on pause and I checked the other things. If I had any new tapes available I would try them.Thanks!