Vintage Car Stereo (Drive Belt)
Discussion
Hi,
Not sure I'm in the right forum, but here goes.
I'm trying to re-commission a Blaupunkt Boston SQM27 (circa early eighties) for my classic car.
The cassette drive belt has come off and I'm not exactly sure what it used to go around (which Pulleys tensioners etc) is there anywhere I can find out?
(I've googled the model/type - no luck)
Regards Jim.
Not sure I'm in the right forum, but here goes.
I'm trying to re-commission a Blaupunkt Boston SQM27 (circa early eighties) for my classic car.
The cassette drive belt has come off and I'm not exactly sure what it used to go around (which Pulleys tensioners etc) is there anywhere I can find out?
(I've googled the model/type - no luck)
Regards Jim.
TonyRPH said:
I used to fix that stuff many moons ago - if you post a picture of the mechanism I can try and help..
A picture of the underside where the belt goes that is.
Oh! OK thank you, I'm a bit busy tonight, I'll have a go tomorrow.A picture of the underside where the belt goes that is.
I've not posted pictures on PH before, I take it it's just the same as any other forum from a photobucket account??
Sorry - I forgot about this.
I have uploaded your image with where I think the belt needs to go - it does look to be a relatively simple mechanism, unless I'm missing something!!!
If the belt doesn't go around the perimeter of the capstan (the large silver flywheel thingy) - it is possible that there is a grooved section underneath (I've highlighted possible size in red).
Please excuse the crude drawing.
To remove the capstan; you will find a split plastic washer on the top side of the mechanism, one you have removed that, the capstan will simply drop out.
Do watch out for any small gears though!!!
I would try to see it in situ first, rather than dropping it out if you can.
ETA:
Here's an example of a capstan that has a smaller pulley underneath it (but still part of the capstan).
You can clearly see that the belt goes around a smaller part beneath the capstan flywheel.
I have uploaded your image with where I think the belt needs to go - it does look to be a relatively simple mechanism, unless I'm missing something!!!
If the belt doesn't go around the perimeter of the capstan (the large silver flywheel thingy) - it is possible that there is a grooved section underneath (I've highlighted possible size in red).
Please excuse the crude drawing.
To remove the capstan; you will find a split plastic washer on the top side of the mechanism, one you have removed that, the capstan will simply drop out.
Do watch out for any small gears though!!!
I would try to see it in situ first, rather than dropping it out if you can.
ETA:
Here's an example of a capstan that has a smaller pulley underneath it (but still part of the capstan).
You can clearly see that the belt goes around a smaller part beneath the capstan flywheel.
Edited by TonyRPH on Friday 8th February 16:02
Hi Tony - thanks for the reply.
I kinda figured the belt went between the motor pulley and capstan (your yellow marking)
Here is the full story, I hope it makes sense!
The stereo was working fine until I 'fixed it' by spraying the whole cassette mech with electrical cleaner - it was very dusty and dirty. When I powered it up after cleaning I noticed that the tape player did not work and deduced that the belt was not driving the spools. I took it all apart and found the drive belt completely off. When I put the drive belt back on it was way to loose between the motor pulley and capstan (no tension whatsoever)I could not figure how it had become stretched??? That is why I thought did it go around something else as well???
So I ordered a load of various drive belts of e-bay and have tried a few between the motor pulley and capstan, these are shorter in length than the original that came off. It does work put plays the tape too slowly.It never played slowly prior to cleaning...
Is it time to stop mucking about and settle for modern stereo?
I kinda figured the belt went between the motor pulley and capstan (your yellow marking)
Here is the full story, I hope it makes sense!
The stereo was working fine until I 'fixed it' by spraying the whole cassette mech with electrical cleaner - it was very dusty and dirty. When I powered it up after cleaning I noticed that the tape player did not work and deduced that the belt was not driving the spools. I took it all apart and found the drive belt completely off. When I put the drive belt back on it was way to loose between the motor pulley and capstan (no tension whatsoever)I could not figure how it had become stretched??? That is why I thought did it go around something else as well???
So I ordered a load of various drive belts of e-bay and have tried a few between the motor pulley and capstan, these are shorter in length than the original that came off. It does work put plays the tape too slowly.It never played slowly prior to cleaning...
Is it time to stop mucking about and settle for modern stereo?
Some cleaning agents and oils will cause a rubber drive belt to soften and subsequently stretch.
A tin of compressed air is your friend here.
The only things I can suggest are to check the voltage on the motor itself - anything above 12v is fine, as IIRC those motors have a built in speed control, which brings me on to my next point.
Does the motor have a hole on the back of it, with a rubber cover? It's tiny hole, about 5mm in diameter. There is a preset resistor behind that hole, to adjust the motor speed - but don't fiddle with this until you have verified you have 12v on the motor.
Also - there is a switch (usually on the side of the mechanism somewhere, but sometimes at the rear - try spraying some contact cleaner into this switch if the voltage to the motor isn't 12v. These switches were known to get dirty contacts and go high resistance, sometimes preventing the motor from turning at all, but often causing slow / speed variations.
If you do have 12v on the motor - then you can spray a little contact cleaner into the hole mentioned above - and then carefully (with a fully insulated flat blade screwdriver) - I used to use a jeweller's screwdriver with insulation tale wrapped around the blade - one layer will do - try and adjust the speed.
Here is a full mechanism with the kind of motor I'm talking about - you can clearly see the hole.
And this should be identical to your capstan - I can see that the belt does indeed run along the outside edge. (I know you have already verified that)
A tin of compressed air is your friend here.
The only things I can suggest are to check the voltage on the motor itself - anything above 12v is fine, as IIRC those motors have a built in speed control, which brings me on to my next point.
Does the motor have a hole on the back of it, with a rubber cover? It's tiny hole, about 5mm in diameter. There is a preset resistor behind that hole, to adjust the motor speed - but don't fiddle with this until you have verified you have 12v on the motor.
Also - there is a switch (usually on the side of the mechanism somewhere, but sometimes at the rear - try spraying some contact cleaner into this switch if the voltage to the motor isn't 12v. These switches were known to get dirty contacts and go high resistance, sometimes preventing the motor from turning at all, but often causing slow / speed variations.
If you do have 12v on the motor - then you can spray a little contact cleaner into the hole mentioned above - and then carefully (with a fully insulated flat blade screwdriver) - I used to use a jeweller's screwdriver with insulation tale wrapped around the blade - one layer will do - try and adjust the speed.
Here is a full mechanism with the kind of motor I'm talking about - you can clearly see the hole.
And this should be identical to your capstan - I can see that the belt does indeed run along the outside edge. (I know you have already verified that)
Jim H said:
I'm 'powering' the stereo off an old Model Train Set Tranformer so - maybe less than 12V?
That could well be the problem.Model train transformers tend to supply 'raw' DC (e.g. unsmoothed) so it's likely to be on the low side, with a lot of ripple.
Are you getting much hum through your speakers?
Also - that radio could well be drawing more current than your transformer can supply - what is the amp rating of your transformer?
Many thanks for all your advice Tony.
So happy it's working again! I hooked it up to a decent battery and that did the trick.
Now if I can ask one final piece of advice? what will be the best way of making something like this I Pod compatible? are these tape-like devices which are ten-a-penny on flea bay any good?
So happy it's working again! I hooked it up to a decent battery and that did the trick.
Now if I can ask one final piece of advice? what will be the best way of making something like this I Pod compatible? are these tape-like devices which are ten-a-penny on flea bay any good?
The tape like devices work (I used to have one myself) but the sound quality wasn't that good. If this doesn't matter to you, then get one.
There are other modifications you could do, but these will require some fairly competent electronics knowledge.
One option is a discreet switch somewhere on the unit, and tapping into the volume control - and then you can switch to an external input.
I seem to recall from my classic car magazines that there are specialists who do these kind of modifications - but I've no idea how much it costs.
There are other modifications you could do, but these will require some fairly competent electronics knowledge.
One option is a discreet switch somewhere on the unit, and tapping into the volume control - and then you can switch to an external input.
I seem to recall from my classic car magazines that there are specialists who do these kind of modifications - but I've no idea how much it costs.
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