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How/where to cross reference diodes

qpagoda

qpagoda

Super Member
I'm trying to find a replacement for a zener diode on the servo board of an Akai GX-280D-ss. The diode on board KD-1096. The part number listed in the service manual is YZ-088A. Closest thing I can find is a WZ-088A on the Vetco Electronics web site. Where can I find a cross reference table of zener diodes?

Thanks.
 
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Well, I guess everyone was at AKFest last week. I'll bump this thread and try again.

How does one find diode substitutions? Are there crossreference substitution tables for diodes? Is it just a matter of finding spec sheets for a particular diode and finding new diodes with similar specs? How close do the specs of the new on have to be to the old one?

My Google searches have turned up exactly zero references to zener diode YZ-088A. I found one reference to WZ-088A. That makes me wonder if the YZ in the Akai manual is a typo. Can anyone out there offer any help?
 
A look at the circuit should be insightful, but normally the '088' would indicate a diode with a nominal value of 8.8V. The physical size should be a strong hint as to its power capabilities.
 
Jan, thanks for the help. With that info, I think I can find a substitution.

EW, schematic for board KD-1096 is attached with the zener outlined in red. Parts list for that board is attached, too. However, since Jan provided the specs for it, I guess the schematic is a moot point. If you were going to figure out the zener from the schematic, would you need the schematic for the entire tape deck, or just the board in question?
 

Attachments

  • KD-1096 parts list.JPG
    KD-1096 parts list.JPG
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  • KD-1096 schematic.jpg
    KD-1096 schematic.jpg
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If it is a 8.8volt zener, there is a error in the schematic, a voltage at 9.3volts are shown at TR253 emitter, so either we are both wrong, or AKAI is :)

(Anyway - i'd scrap the entire circuit and mount a LM7824 instead :)
 
Zeners aren't terribly linear...shove a little more current down its throat and the voltage rises. Also, back then the suffix generally determined a sort of sub-range for a particular zener. In this case the 'A' might mean a nominal zener voltage of something like 9.0 to 9.3 volts, or some such.
 
Wow. And I thought this would be a simple question.

Thanks for providing info about the whys. The repressed engineer in me wants to know how to figure out what to do, not just what to do.
 
qpagoda said:
Wow. And I thought this would be a simple question.

Thanks for providing info about the whys. The repressed engineer in me wants to know how to figure out what to do, not just what to do.
Click to expand...

a true engineer would look at the schematic, note the emitter voltage at TR253 are shown as 9.3 volts. The resistor at top R253 are 2.700 Ohms - that gives a current ~ 0.0054Amps ( 5.4 milliamps )

this current passes the Zener

now add the current from R251 and 252 - my estimate 34volt-25 ~9volt / (r251 + r252) ~ 3000 ohm ~ app. 3milliamps - total app. 9milliamps and a zener voltage at 9.3 would give a powerdissipation at merely 90milliwatts.

any 200mW 9.1 or 9.3 zener should work :)

So a 200mW zener is on the safe side ~
 
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