ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Afternoon ,
Hope all are safe and well ,
So having solved the cd player issue I've now moved on to the tape deck. I've fitted a new belt (it's the single belt tape deck) cleaned up a sticky mechanism and all is good but its a bit temperamental on fast forward and rewind. I have notice the pinch roller is in slight contact with the tape when in fast forward or rewind and the brakes and very close to the take up and spool reels. I have looked at the service manual for a way to adjust the travel of the heads etc but couldn't see an adjustment procedure .Has any body come across this issue before and would there be a way to adjust this ?
Many thanks
Dave
It would appear I looked for the information poorly , it is clearly in the service manual .
Problem solved
How did you resolve the cd problem in the end Dave?It seemed to be developing into "the tale of the ancient mariner"?
Nick
You got there in the end,better than admitting defeat?
There is a separate motor for wind/rewind(M2,diagram F)but this also drive's the take up in each direction when in play mode.
Does the mech play and auto-reverse normally?
Are all the microswitches contacting ok at the rear of the cassette compartment?
I'd put way too much time and love into the cd mech to give up on it .
Yes I've got the diagram F , and all is good on playback in both directions , the M2 motor is fine on playback , hoping its not a logic problem somwhere .
I did give the micro switches a clean but I'll double check them .
Does the carriage pull back far enough in wind/rewind?
Does auto reverse function normally?
Does it try to drive in wind/rewind?
It's quite common for the turntables to become tight due to "gummy" grease on the spindles?
Did you use one of Martins belts?It's the only replacement one that works properly!
It occasionally works , but mostly doesn't even try , interestingly there is 3.46 vdc at motor 2 on playback but 0 vdc on wind / rewind.
I have cleaned the spindles on both spool and take up reels , and also stripped and cleaned the wind cog spindle ,
Its is indeed one of Martins belts I used .
I'm thinking motor or its power supply , which comes from the psu on the decoder board , but I have rebuilt that so unlikely ?
Ok Dave.
Check the voltage at 20IC28 pin 2 when you select wind,it should increase in voltage.If it doesn't ,check 20TR50 and 51.and 20IC22 pin 5
You probably don't want to go in there again,but I think that you may need to investigate the tape "mecha-state" switch too,which is buried in the mechanism.It tells the computer whereabouts the mechanism is in it's cycle,and may be gummed up or contacts oxidised?It's shown as item 9378 in drawing 4-5.There is another microswitch in the mech too,which is 93S4.
Same principle and culpability as the "mode switch" in a VCR,remember them?
It's a clever tape mech,and has been reliable over the years generally.
Thanks Nick ,
I had the deck out so I went in and cleaned the "mecha state " switch , and S4 ,put back together and ... nothing not even playback from M2 now , hastilly swiched off .
Applied 9v from a battery directly to M2 with no wiring attached and nothing , metered across it and a dead short , so it would seem the motor is at fault here.
Ooh er Dave!!
I don't think I've ever had one of those motor's fail!
It seems as though it didn't like the higher voltage which is applied in wind/rewind ?
I have a spare mech among my treasure trove,but I can't get at it under the present circumstances,alas.
I wonder if you can dismantle the motor(fiddly)to investigate the internal's further?
Ooh eeerr indeed !! ,
However I did get into the motor , I would not recomend it , if you do remove the cog and take the housing off upwards holding the rotor shaft so the magnet does not suck it back in , otherwise , as I did , a washer will merily tear its way through the bushes causing all maner of damage and trouble .
Luckily I manged to repair it , and now have a working motor !! which shows 120 ohms between the terminals , but alas after an initial wind/rewind success we are back to nothing (motor still works when powered externally) , so I will be checking the op amp and transitors Nick suggested .
We are getting function all the way through the circuit , so I am back to thinking it has to be a dodgy motor or maybe the mechanism is still a bit gummed up.
I have checked TR50 and 51 and they are good ,we have dc voltage output on pin 5 of IC22 when wind/rewind selcted , and pin 2 of IC28 , is around 5 vdc on playback and 11vdc on wind / rewind.
The case continues.....
So now I have come to the conclusion that it is an issue with the carriage and brake positions , so something to do with the mecha state switch possibly ? or control of the motor that drives it .
The brakes certainly are not moving out the way of the take up and supply spools at all ....
more cleaning and investigation to do .
This morning I have stripped and cleaned the deck again , but still inconsitent function. I have noticed a pattern though .
It works for a couple of times , then I can hear the M3 motor that operates the carriage and head reverse over running , then the cassette deck shuts down , capstan motor goes off. Turn the system off and on and we can repeat the strange behaviour.
All wiring is good to and from the cassette .
I'm going to poke around the control board to see whats going on there.
If this is the early deck type, did you check the worm gear?They tend to brack along the spindle. Glue with Araldite Standard.
Martin
Yes , early type deck , no I did not check the worm gear , I have now it was no longer attached to the spindle , I have glued .
Will report back once set , but guessing that was the problem .
Many thanks Martin
The deck is better , but still not well . The carriage and brakes are certainly not getting out the way sufficently for forward and rewind , so we are very sluggish.
And now we also have playback in one direction only , wind motor is still checking good when powered externally , capstan motor is good.
The deck does not shut down anymore though , so progress there.
confused ,