Need help finding replacement diode for technics TT

[Chris Lauver]

Hey guys, need help finding a replacement diode for my Technics TT. The part number is MA26TO-A. I can't find anything on here or internet. I have attached a pic. Thanks for your help.

 

[nj pheonix]

Do you know for fact that it's bad?
Do you have a schematic showing it in circuit?

 

[Chris Lauver]

Do you know for fact that it's bad?
Do you have a schematic showing it in circuit?

I have pulled it out of the board and tested with multi meter on diode test and it has no continuity no matter which way the leads. Here is a pic of the scematic.

 

[Robisme]

What kind of meter is it? I have heard that some meters can't measure a diode like that. Instead of .6 or .7 volts, it could be 1.8 or 2.1 volts.

Can you measure the voltage across it in circuit with the gear powered up? Also, from ground to each side of it?

Rob

 

[Chris Lauver]

What kind of meter is it? I have heard that some meters can't measure a diode like that. Instead of .6 or .7 volts, it could be 1.8 or 2.1 volts.

Can you measure the voltage across it in circuit with the gear powered up? Also, from ground to each side of it?

Rob

The tester is Klein MM300. I can't check it in circuit currently, as I have the whole board out. Any other way to test? Trying to resurrect an old Technics sl-1600mk2.

 

[Robisme]

You could probably test it with a 9 volt battery and a 1k ohm resistor in a series circuit. Check the voltage drop across the diode. May have to be a 100 ohm.

You may be able to replace that diode with three series 1N4148 diodes. Looks like it's on the output of that IC. What connects to pin 1 of that IC?

Rob

 

[regore]

It's actually three diodes in series. The tester voltage is not high enough to forward bias all three diodes. I'd say D-426 is not your problem.

 

[Chris Lauver]

You could probably test it with a 9 volt battery and a 1k ohm resistor in a series circuit. Check the voltage drop across the diode. May have to be a 100 ohm.

You may be able to replace that diode with three series 1N4148 diodes. Looks like it's on the output of that IC. What connects to pin 1 of that IC?

Rob

Assume you mean IC428. Pin 1 is 12v supply in. I think your saying the multi meter doesn't have enough voltage to test the diode? Looks like it is being supplied with 6v in circuit.

 

[nj pheonix]

Glad I got the ball rolling a bit.
Sorry i can't be more helpful here though

 

[Robisme]

That's interesting. The datasheet shows pin 1 being output 1.

What is the problem with the TT?

Rob

 

[quaddriver]

here:

https://www.datasheetarchive.com/pd...26e51e8467376ecda6b247fa06f&type=M&term=MA26T

It appears to be temp stable with Vf from 1.78-1.94v so measure up 3 1N4148 or 1N914's and get close. Most the 1N4148s I measure go between .550-.565v