Just purchased a Technics twin cassette deck model no RS-X101 off eBay and dropped a right gooly.
I assumed that it plugged into the mains, but it doesn't, it has a very small flat 3pin plug on the back to connect to a lead from the amplifier which I do not have.
I am hoping that someone is able to let me know what the 3 pins are and the orientation so that I can make up a power supply instead of going to the expense of purchasing an amp which I do not really need.
Jim G
If you are prepared to put good money after bad the Technics service manuals are online for about $5 (Tek scope manuals were free elsewhere).
I would be inclined to take a look inside and then make an educated guess about what power it requires. YMMV
Regards, Martin Brown
This place might be worth looking at. I got a couple of DIN cables from them to get my old Goodmans Module 80 receiver working again.
Dtmwfi, but it looks like 12.5v AC centre tapped, the centre pin on the connector helpfully being the centre tap. Check for yourself in case I've read the schem wrong!
Schem for the corresponding amp here:
Lee
Just read that back and it looks ambiguous, I meant 12v-0v-12v ac, hope that's clearer :)
This appears to match the SU-X101 amplifier.
Unfortunately the two on ebay are not, as you may have discovered, cheap. It might be worth setting up a search with email alerts in case one comes up. There's a complete system in Motherwell
I'd be tempted to look inside and see if it actually has a transformer. If its part of a midi system they were quite small and the transformer was in the amp so it did not induce hum into the tape heads. However having said that, I've not ever seen a Technics that had no mains input. Many of them use the old figure of 8 connectors, but there is one from the us market that looks like a figure of 8 with an extra pin slightly above the other two. If its one of those, one might be able to find one as Dell laptops a few years ago had them on their psu mains input. Brian
I've not seen a transistor design which uses this principle - although it was quite common with valve types.
Do you meand a C5/C6?
I don't think so.
I gave one of these systems to the children some years ago. My memory is that the amplifier is the base PSU for the stack of devices and the interconnects for power are proprietary. It gives the advantage that one switch controls the power to all devices.
Thanks Lee, I downloaded the file but can not see where you would think it is a 12.5V AC centre tapped. Could you point me a little closer ?
Jim G
If it is this, then that is easy to sort out. Just put a different connector on rear panel and connect to circuit board.
Jim G
That's what I'd do if it were mains too.
"cloverleaf".
Ok lets see if I can explain this without pictures.... :)
On page 8 of the pdf (actually page 9 of the document) there is a block which says section B Input/Output terminal, just to the right of this it says "Tape power supply" and show pins 1,2 and 3 with legend a,b and c concatenated into one line. If you follow this single line across the document to pdf page 10 (document page 13) the single line again becomes "a,b,c" at the main transformer (pins 3,4,5) which shows 12.5v across each half of the centre tap.
So as long as I'm reading it correctly you should just need a simple
12v-0v-12v transformer. Of course you are going to have to guess at a current rating, because there is no indication of that in the document.Lee
Many thanks Lee, I was looking at wrong part of circuit. Further along page
13..... Yep, just a transformer needed. I don't think it would need more than 2amp, so will go digging in my shed. Thanks again Jim G
If the first components in the tape deck is a bridge rectifier then DC (9/10V) from a wall wart type supply to the outer two pins may also work.
But then you'll be running two of the diodes at 100% duty ratio, and the two will sit idle, rather than all four having a 50% duty ratio, so you might push the rectifier to an early death ...
I can see your reasoning, but I'm fairly certain that this deck is going to want a dual rail supply for the op amps and it's unlikely to work from a single ended supply. Plus 12v ac gives roughly 17v dc once rectified and smoothed so 10v would probably be too low anyway....
Lee
There was a long argument in one of the electronics groups about this very point - I don't think it was resolved for either side....
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