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Hello all!
I was recently working to repair my car's cassette deck, but not being an audio person, I'm not entirely sure what might be the problem with it. The car's radio is a '91 Delco, and when a cassette is placed inside, the drive spins too quickly resulting in the audio sounding very high pitched and sped up.
I have cleaned a lot of the internal components carefully with rubbing alcohol and a Q-tip, and have also tried adjusting the potentiometer on the drive motor but it is still out of normal sounding range. I've looked over the electronics and could not find any burnt items or other troubling spots.
Does anyone have any other ideas as to what might be causing this issue? Any input is greatly appreciated!
Pretty sure all cassette motors have a speed adjustment t screw on them. There are a lot of different cassette motors so not all the adjustment screws will look the same and some might be hard to locate,... but there should be one somewhere on the motor itself.
Edit: I didn't verify this screw was this cassette motors adjustment screw before posting the pic,..... picture is for reference !
Last edited by John in RI; 05-10-2018 at 10:52 PM.
Reason: EDIT:
Thanks for the suggestion, John! My adjustment screw is in the same location as the one pictured above and does have an effect on the playing speed for sure, but unfortunately I already tried adjusting it before posting and it will not slow the motor down enough to be in the proper "normal playing" range.
That said, I was surprised to find that I could turn the screw (slowing down the motor) until it suddenly reached a point where it basically jumped up to it's previously fast speed once more, and I'm not sure that is normal?
Haha, I was rather surprised when it happened, as I figured the screw would have a cutoff point where it would no longer turn. The screw also did not have much of an adjustment range, which almost makes me wonder if the motor as a whole might be behind this speed issue...
Good idea. Just went through and checked all of the pulleys, but it looks like the belt is still in the proper groove on each of them. Seems to be narrowing down to a motor/electrical problem. Honestly I'm just surprised as I would've thought an old motor would play tapes slower rather than faster...
Plugged the cassette deck back up to the car today, and while watching it work, noticed that one of the pinch rollers was not making contact with the tape. This very well might be my problem!
Plugged the cassette deck back up to the car today, and while watching it work, noticed that one of the pinch rollers was not making contact with the tape. This very well might be my problem!
Haha, more or less I suppose! Looks like the pinch roller guide is getting caught on a plate under the drive plate, and I don't really understand why or how to adjust this, so I might just have to take it to a repair shop and have them take a look at it. Cassette decks are definitely not my forte, but I'm at least glad to know what's wrong.
The mechanism probably is sticky from the lubes drying out over the years.
You have nothing to lose by squirting some WD-40 into a cup and dip a toothpick
into it and apply small drops at all the sliding and rotating points. Then work the
mechanism to see if things free up.
Thanks guys! Though I'm not entirely sure WD40 will help me out on this one. Sorry these aren't the best photos, but hopefully they will help all the same!
In the first photo, you can see the pinch roller assembly. At the bottom of the assembly, there is a little round wheel on the back pin. As the pinch roller moves toward the cassette when engaged, that bottom wheel contacts an underlying plate which is riveted onto the overall assembly, preventing adjustment of it. When it contacts the plate, the pinch roller begins to angle prematurely and this prevents contact with the tape pin, effectively preventing the pinch roller from "pinching" the tape. This is easier seen in the second photo.
I'm really not sure what is at fault here. Is the wheel supposed to contact that underlying plate and is somehow out of adjustment? Or is it supposed to avoid the plate entirely and just progress forward uninhibited?
What I can tell you is that that pinch roller will be all the way up against the capstan shaft in PLAY mode.
If a cassette was inserted, the tape would be between those 2 parts. The speed of that shaft is your PLAY speed.
When you do a music search (cue, review), that mechanism gets pulled back slightly (as your 2nd pic shows) so that the tape is still up against the tape head, but the tape can now be pulled through there faster by either drive post depending if it's CUE or REVIEW.
For whatever reason, your mechanism is stuck in CUE.
This might be as simple as a dirty or stuck microswitch associated with the cue function.
What I can tell you is that that pinch roller will be all the way up against the capstan shaft in PLAY mode.
If a cassette was inserted, the tape would be between those 2 parts. The speed of that shaft is your PLAY speed.
When you do a music search (cue, review), that mechanism gets pulled back slightly (as your 2nd pic shows) so that the tape is still up against the tape head, but the tape can now be pulled through there faster by either drive post depending if it's CUE or REVIEW.
For whatever reason, your mechanism is stuck in CUE.
This might be as simple as a dirty or stuck microswitch associated with the cue function.
Gotcha there, and good points. What doesn't make sense to me though, is how only that one pinch roller is stuck in CUE mode when playing a cassette, while the rest of the assembly moves forward just fine, making contact with the tape. The spring that applies force to the two rollers seems to work on both rollers just fine. Wouldn't the microswitch you mentioned affect the whole assembly, rather than just that one pinch roller? Sorry if I'm mistaken, just trying to make sense of what I'm seeing.
It's so hard to troubleshoot over the internet. If I had it in my hands, it would be much easier.
Do you have any contact cleaner? If so, clean every switch.
Spray contact cleaner inside the switch, and then work it on & off a bunch of times. Use alcohol and a q-tip to clean all the rubber drives and tape head. Clean any drive belts too.
When the tape is pinched between that rubber roller and capstan in PLAY mode, the two posts that go through the cassette have friction "clutches" in them and they turn faster while slipping to take up the tape. So in PLAY, let's say the right post is driving and the left is freewheeling. Now you activate CUE. The mechanism slightly retracts enough to let the tape's speed to not be slowed by the pinch roller. Also the right post now gets kicked into a higher speed (FF) while the tape is still touching the tape head. CUE works by detecting the blank spots between the songs. When one is detected, the mechanism pops back into PLAY mode.
Something has your unit stuck in CUE mode - I just can't say exactly what IT is.
A tape head cleaner cassette makes troubleshooting easier, but some units may reject it because they need to see tape movement. Work every trip lever you can find in this mechanism. One of them should get it back in PLAY mode.
Something must be out of sync.
It's so hard to troubleshoot over the internet. If I had it in my hands, it would be much easier.
Do you have any contact cleaner? If so, clean every switch.
Spray contact cleaner inside the switch, and then work it on & off a bunch of times. Use alcohol and a q-tip to clean all the rubber drives and tape head. Clean any drive belts too.
When the tape is pinched between that rubber roller and capstan in PLAY mode, the two posts that go through the cassette have friction "clutches" in them and they turn faster while slipping to take up the tape. So in PLAY, let's say the right post is driving and the left is freewheeling. Now you activate CUE. The mechanism slightly retracts enough to let the tape's speed to not be slowed by the pinch roller. Also the right post now gets kicked into a higher speed (FF) while the tape is still touching the tape head. CUE works by detecting the blank spots between the songs. When one is detected, the mechanism pops back into PLAY mode.
Something has your unit stuck in CUE mode - I just can't say exactly what IT is.
A tape head cleaner cassette makes troubleshooting easier, but some units may reject it because they need to see tape movement. Work every trip lever you can find in this mechanism. One of them should get it back in PLAY mode.
Something must be out of sync.
Ohhh my apologies, I see what you are saying now. I'll give those things and try and keep my fingers crossed! Thanks again for helping this clueless audio rookie! Haha.
05-10-2018, 12:51 PM
