Lasonic 975, funny stuff - help if you can!

Skip sent me this video after he rebelted my 975. Tell me anything you can about what it would take to fix it. Thanks!

well just seeing that pic i am already dizzy so i am of no help

well the volume going up remember you have voltage being used up by the amp ,, the motor should have its own regulator but i belive the dual cassette has a seperate board for the motor if the deck has the dubbing feature,, so the first thing is to check powersupply before anything else

Now that is cool!!! It's the first "gain-pitch control" I've seen in my life!!!

Anyone have an idea of what kind of numbers to be looking for when testing the power supply?

The radio and aux-in work 100% and don't loose any power or volume even at full crank.

blu_fuz said:

Anyone have an idea of what kind of numbers to be looking for when testing the power supply?

The radio and aux-in work 100% and don't loose any power or volume even at full crank.

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Maybe a bad resistor before motor Also there is a switch for high/normal speed, make sure its set on normal because it will speed up motor..

Motors that do not have integral speed controllers will have some form of separate speed controller and/or the motor might be driven by a "driver," and/or the motor power rail is sometimes powered by a "voltage regulator." All of functions are performed by or include a semiconductor (transistor). When overheated, a condition called thermal runaway occurs which causes the transistor to pass more current, which further causes it to heat up even more, which of course causes higher operating temperature, etc. etc. etc until it either blows up, or almost blows up. This is worth investigating. All the appurtenant and related circuitry also will need to be checked. Without a schematic or service manual, this is no easy task.

So basically I shouldn't use the cassettes Thanks NORM.

I know this is quite off topic...but does the 975 have a high speed dubbing setting?
Tape 1 plays very too fast on mine and tape B is not working...
I have not seen it inperson yet so I really would like to know if it is something easy to fix...

mmcodomino said:

I know this is quite off topic...but does the 975 have a high speed dubbing setting?
Tape 1 plays very too fast on mine and tape B is not working...
I have not seen it inperson yet so I really would like to know if it is something easy to fix...

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Yes there is a switch on it, high/norm. speed

baddboybill said:

mmcodomino said:

I know this is quite off topic...but does the 975 have a high speed dubbing setting?
Tape 1 plays very too fast on mine and tape B is not working...
I have not seen it inperson yet so I really would like to know if it is something easy to fix...

Click to expand...

Yes there is a switch on it, high/norm. speed

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Thanks Means it just needs new belts and a switch pressed to fix it

blu_fuz said:

So basically I shouldn't use the cassettes Thanks NORM.

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I'm just making a suggestion as to where to look for the problem. Something has failed, or is failing. If I had a schematic here, I could make a suggestion. Because no such schematic exists that I'm aware of, then YOU are the man on the spot and will need to do the tracing to find where the issue might be.

I know, I know, I just need more tools, time, and .... time to get to something like this. It will probably stay the way it is forever or atleast until I can get to it.

Anyone delt with something like this and fixed it? Any help is appreciated. Thanks!

blu_fuz said:

Anyone delt with something like this and fixed it? Any help is appreciated. Thanks!

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Dealing with the same this on my 935. Nope haven't fixed it.

Tape B plays too fast, tape A not at all and tape A is clicking like crazy. I just did belts, but no difference.

I wonder if replacing the PC board behind the deck's would fix it, if that's where the speed controller is?

Yeah, not sure where the speed controller is but I want to find that damn thing and fix it!

blu_fuz said:

Yeah, not sure where the speed controller is but I want to find that damn thing and fix it!

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I forgot but are both decks the same speed? I do know there is only one motor for both decks and maybe there is a problem with the high/ low speed switch

I honestly don't know - I am so stupid when it comes to this kind of thing, sorry

I was going to try to isolate the speed controler. Both the 975 & 935 have a PC board that may be the controler. If so I was going to try to replace it.

I was also wondering i f I could put a single speed motor in there and by pass the speed controler all together. I have no need to do high speed doubing on mine.

Also, on my radio the speed control button does work, but the tapes are already running fast. When I push the button, they just go faster!