Is that a Shotzzkey in your pocket? Sansui D-90

BarryJ

New Member
My story.

Over the last couple of days a friend asked me to look at his garage sale purchased Sansui D-90 tape deck. He's had it for five years and it's never ran. I found a misaligned leaf switch, the kind that has two flat pieces of flexible copper foil that are separated but when the "play" button is pressed, make contact and things run. I had a look, repositioned the switch, and it was all good! I returned the deck to my friend who was thrilled.

24 hours later he reports something happened and the magic smoke left the machine and now it powers up but nothing else. He brought it back to me.

Immediately I saw that that funky switch had somehow slipped and made contact with the metal body of the deck's chassis. The only damage I could see was to diode ZD601. It has markings IR 10E on the body. It was toast but there was no other obvious damage to anything I could see... no burn marks, no heat damage indications.

So I replaced it with an IN4007. So now what happens is when the "play" button is pressed the motor turns half a turn and stops. I measured voltage at the switch. It should be 14v DC... what I saw was a voltage that was building up from 0 to 14 and then when "play" is pressed... back to 0 - only to start to build up again again when the stop button is pressed.

Now the diode in question is a Shotzzkey. My question is... where do I find one of those suckers and would fitting that diode solve the voltage issue?

Any thoughts or suggestions would be appreciated.

Barry
 
Greetings from RojoLand!

The fact that the IR10E diode is marked "ZD601" makes me believe it's a Zener. But I couldn't find anything online about an IR10E (should be an International Rectifier part given that number). A 1N4007 (not "IN," by the way) will not properly substitute for any Zener diode. Not sure I've ever heard of a Schottky Zener diode either (not "Shotzzkey"—Walter Schottky was a physicist involved with transistor research), but that doesn't mean much. If that is in fact a Zener diode, be aware that the banded end of the diode should go to the more positive of the two terminals; in other words, it's backwards.

Could you please post the relevant part of the schematic? Thanks!

Take care,

J. E. Knox "The Victor Freak"
 
I'll reply to my own post.

I just go my head out of that deck again. It's not a Shotzzkey diode after all. The confusion came from the schematic. There are two diodes with the same number 601. I happened to be looking at ZD601 which is a Shotzzkey. It's fine. The diode I replaced is indeed labled IR 10E. I replaced it with the IN4007. But the charging voltage still has me confused.

Sorry about my mascinations.

Again... any thoughts are appreciated.

Barry
 
Greetings from RojoLand!

Could you please post the relevant part of the schematic? Thanks!

Take care,

J. E. Knox "The Victor Freak"

Thanks so much.... I did a screen grab of the area I've been looking at.
 

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Greetings from RojoLand!

Thanks for the schematic! Unfortunately, it's not high enough resolution for me to clearly read the parts list. Basically, you're saying diode D601 (as opposed to ZD601) is the one you replaced. If I'm seeing the parts list correctly, it states 10E-2 for diode D601. I did find a datasheet for that part number, and a 1N4007 is OKeh to use in its place. The 10E-2 is a 200 PIV (peak inverse voltage) 1 A rectifier diode with non-repetitive PIV of 400. The 1N4007 is rated at 1 kV PIV. No problems there. As long as you installed it with the banded end in the same position as the original, you should be OKeh. I'm at a loss to explain the deck symptom though. It's just too hard for me to read the schematic. Sorry!

The symbol shown on the schematic for ZD601 is that of a Zener diode, which is logical. There is no such thing as a Schottky Zener diode, as it turns out. That Zener appears to be part of a voltage-regulator circuit.

Take care,

J. E. Knox "The Victor Freak"
 
Greetings from RojoLand!
I'm at a loss to explain the deck symptom though. It's just too hard for me to read the schematic. Sorry!

Take care,

J. E. Knox "The Victor Freak"


Yeah, it is just so strange. It is like a capacitor is charging but looses that charge when the play switch is hit. If you wish, you can connect with me by PM... and I can send that part layout in higher resolution. However, I do appreciate your comments and thoughts.

Barry
 
It is clear that it is a Zener diode from the service manual.

A 10 second Google search give the specs.

upload_2017-11-15_19-51-30.png

RD 10E-C is what is listed in the service manual.

Here it is in the schematic (BTW what you posted is the board layout, not the schematic).

It shows it as a Zener diode and a regular diode such as you tried will not work. The Zener diode establishes the output voltage of TR601.

upload_2017-11-15_19-55-52.png

BTW, ZD601 is just the schematic reference number not the device part number, much like TR601 is not the part of of the transistor.
 
It is clear that it is a Zener diode from the service manual.

BTW, ZD601 is just the schematic reference number not the device part number, much like TR601 is not the part of of the transistor.

Man, I am not doing well tonight. You have the schematic! Amazing. Thank you. I'm off to see if I can find a Zener with those specs!
 
Greetings from RojoLand!

I'm a bit confused now — didn't the OP state it was D601, NOT ZD601, that he subbed with a 1N4007?

Take care,

J. E. Knox "The Victor Freak"
 
Greetings from RojoLand!

I'm a bit confused now — didn't the OP state it was D601, NOT ZD601, that he subbed with a 1N4007?

Take care,

J. E. Knox "The Victor Freak"

I can understand the confusion. Yes, I replaced D601 with a 1N4007. I've attached a portion of the schematic to show you. The clip will also show ZD601.

You suggested the 1N4007 would not work and that a Zener would be required. I'm in the process of looking for that Zener and a Leaf switch for the deck.

Thanks

Barry
 

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As I look at the schematic, I wonder if when switch 701 went to ground, could that have damaged cap 602?
 
So it was not ZD601 that was damaged as you said?

First you have to be clear about which diode was damaged and replaced. You can see the difference in the section of the schematic that I posted.

ZD601 is a zener.

D601 is not.

No, the capacitor would not likely damaged.
 
You are right! Look at this!

The burnt bit, really burnt bit was on the bottom of the resistor. You are amazing Thanks.
 

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Finally managed to find a resistor. Made the repair and it is all good again! Many thanks to all who helped with this.

Barry
 
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