Sanyo M9935k Cassette sound distortion

Status
Not open for further replies.

OsmiumTetroxide

Member (SA)
I'm new to the forum, but I can feel myself quickly becoming a collector.

I picked up an M9935k at an estate sale for $5 last year, and since then it has traveled everywhere with me, and gotten many compliments. It was in excellent condition, however I was devastated when it got dropped a couple of feet while someone was helping me move back from college.

A couple of the internal mounting pillars sheared off, but not enough that boards were completely loose. However, about a month later, I noticed issues with the audio coming from the cassette player.

Only the bass part of the audio is playing, so I can't hear the lyrics section of the track. Also, it seems that only the right speaker is playing any audio. I have checked the wires going directly to the speakers. However, when I play audio from the tuner, it sounds fine. The speakers are just as good as they were before. The issue stems only from the tape player. I use a tape player aux cord to play music from my phone, so I tend to use it quite a bit.

Any idea where the problem could be? I haven't been able to find any broken solder joints, and nothing looks out of the ordinary. I have yet to remove the main board and check underneath, but I had thought that I would be able to tell. Is it most likely in a joint that isn't obvious, in the board, or maybe in the tape pickup?

Thanks, any advice is much appreciated.
 

Fatdog

Well-Known Member
Staff member
Welcome aboard!

Most of the M9935s have issues with the volume potentiometer. No sound, sound out of only one speaker, huge fluctuations in volume, muffled sound, and high sensitivity could be (but not necessarily) symptoms of a wonky volume potentiometer. Member jaetee disassembled and cleaned his volume pot and has had no further issues.

Also, since it seems to be localized to the cassette player, check to see if the player head is loose. Is it still properly aligned? When was the last time it was properly cleaned and demagnetized? It probably wouldn't hurt to spray some contact cleaner in the record bar and move it back and forth a few times too.

Record Bar Switch
 

OsmiumTetroxide

Member (SA)
Thanks very much for the response! I've tried mucking around with the record bar and the player head. However, that hasn't changed the muffled sound quality or the fact that it only plays the bass track. I'm using a tape player aux adapter in it, and that is where I'm getting the problem. With a real tape, it sounds odd because the speed is too slow, and I can't really tell but it seems to also have the same issue. I'm leaning towards just doing what was done in this post:

https://boomboxery.com/forum/index.php/topic/9207-sanyo-9935k-restoration-and-line-in/?hl=m9935#entry115893
 
Status
Not open for further replies.