Yamaha MX-1000 repair

The 4.3v zenner is probably gone. A bunch of those 1/4w resistors will also be gone.
Search previous posts on this issue and you will find many answers. Good luck!
 
an update and some questions

rottalpha said:
The 4.3v zenner is probably gone.
Click to expand...
I measure with my multimeter which has a diode stand, this zener measures both way's so I think you are right. Anyway I will replace this one.

A bunch of those 1/4w resistors will also be gone.
Click to expand...
So far I found R384 (with the modification capacitor of 2,2 nF) of the 1/4W resitors was burned.
The power-transistors base resistors R352,356,358,360.
R368 which has been shorted by Q318.

Search previous posts on this issue and you will find many answers. Good luck!
Click to expand...
Which post do you mean in particular?



avionic said:
With that kind of damage. There is bound to be a handful of burnt up resistors , diodes and even capacitors.
Click to expand...

This is the list of damaged parts I found till now:

Q310 2SA970
Q312 2SC2240
Q316 2SA1306(B)
Q318 2SC3280
Q322 2SC3280
Q324 2SA1301
Q326 2SC3280
Q330 2SA1145

R372 0.22
R376 0.22
R378 0.22
R380 0.22
R352 2.2
R356 2.2
R358 2.2
R360 2.2
R368 68
R384 4700

D334 RD4.3FB

I did search this forum and other sites and made this list of replacements. Do you think these are the good types?

Original --> Replacement
2SA970 --> KSA992
2SA1145 -->KSA1013YTA
2SC2240 --> KSC1845
2SC2705 --> KSC2383YTA
2SA1306(B) --> 2SA1837
2SC3298(B) -->2SC4793
2SA1358 --> 2SC3902T
2SC3421 --> BD139?
2SA1301 --> 2SA1943
2SC3280 --> 2SC5200
2SA1302 --> MJL1302
2SC3281 --> MJL3281

I read that I should replace all the end- and power-transistors, what about the others that seem to be oké?

Thanks in advance!
 
RichWare said:
I measure with my multimeter which has a diode stand, this zener measures both way's so I think you are right. Anyway I will replace this one.



So far I found R384 (with the modification capacitor of 2,2 nF) of the 1/4W resitors was burned.
The power-transistors base resistors R352,356,358,360.
R368 which has been shorted by Q318.


Which post do you mean in particular?





This is the list of damaged parts I found till now:

Q310 2SA970
Q312 2SC2240
Q316 2SA1306(B)
Q318 2SC3280
Q322 2SC3280
Q324 2SA1301
Q326 2SC3280
Q330 2SA1145

R372 0.22
R376 0.22
R378 0.22
R380 0.22
R352 2.2
R356 2.2
R358 2.2
R360 2.2
R368 68
R384 4700

D334 RD4.3FB

I did search this forum and other sites and made this list of replacements. Do you think these are the good types?

Original --> Replacement
2SA970 --> KSA992
2SA1145 -->KSA1013YTA
2SC2240 --> KSC1845
2SC2705 --> KSC2383YTA
2SA1306(B) --> 2SA1837
2SC3298(B) -->2SC4793
2SA1358 --> 2SC3902T
2SC3421 --> BD139?
2SA1301 --> 2SA1943
2SC3280 --> 2SC5200
2SA1302 --> MJL1302
2SC3281 --> MJL3281



I read that I should replace all the end- and power-transistors, what about the others that seem to be oké?



Thanks in advance!
Click to expand...

The zenner is suppose to show resistance both ways, with one direction showing resistance in the megaohm range. If resistance is low in both directions, then is gone. I would be really surprised if it is still good. i would replace it.



Change them in pairs (drivers) If the others are good, I would leave them alone.

Most parts are available at Mouser.

2sa3280, 2sa3281; 2sa1301, 2sa1302 could be replaced by MJL3281/MJL1302 or as suggested by Avionic, by MJL4281/MJL4302

Search my previous post on this issue. I went through some of the same pain.
http://www.audiokarma.org/forums/showthread.php?t=602776&highlight=yamaha+mx-1000&page=3
 
Last edited:
rottalpha said:
The zenner is suppose to show resistance both ways, with one direction showing resistance in the megaohm range. If resistance is low in both directions, then is gone. I would be really surprised if it is still good. i would replace it.
Click to expand...
This 4.3 V 1 W zenerdiode is showing in both directions about 1.6 kΩ, it's in the I-AMP circuit so no big supprise it's gone. The original type RD4.3FB isn't available, do you think I could replace it with a regular one like BZX85C4V3?


@Avionic, do you think the replacement of Q310 2SA970 --> KSA992, Q312 2SC2240 --> KSC1845, Q316 2SA1306(B) --> 2SA1837 and Q330 2SA1145 --> KSA1013YTA is a good choice?
 
RichWare said:
The original type RD4.3FB isn't available, do you think I could replace it with a regular one like BZX85C4V3?
Click to expand...

Yes, you will have no problem. I fixed a M80 a few months ago, and shares some references with your amplifier. If it helps, these are the replacements I used.
 
Last edited:
parts ordered

Hello,

I did order the available original transistors from B+D.
I ordered replacements for the following transistors:
2SA1306(B) --> 2SA1606
2SC3298(B) --> 2SC4159
2SA1301 --> MJL1302
2SC3280 --> MJL3281
2SA1302 --> MJL1302
2SC3281 --> MJL3281

I'm going to replace all zeners and electrolytic capacitors and some of the resistors.
Now waiting for the shipment arrives...
 
For the capacitors that aren't in the audio path I used Panasonic FM, cheap and reliable.
 
I gotta ask. Where in the work are we to get 47000uf 63v caps or the 40000uf 50v caps? My 1000 is running fine but I think I see about a 1/16 in bulge at the top. Or is a very slight bulge normal on the massive caps. Sorry to hijack. :)
 
Crazeehorse said:
I gotta ask. Where in the work are we to get 47000uf 63v caps or the 40000uf 50v caps? My 1000 is running fine but I think I see about a 1/16 in bulge at the top. Or is a very slight bulge normal on the massive caps. Sorry to hijack. :)
Click to expand...

Push in on the bulge. Its likely just plastic shrinkage from internal amplifier heat. If the plastic pushes in to a flat surface ,your still good to go. If you have several hundred dollars for a couple cases of caps you can most likely special order them.
 
Hi,

I've just bought a MX-1000, it seems to be working fine, except the LCD and Leds, all up and freezed. (Photo 1).

help!!!

Thx,

Edu
 

Attachments

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@Edubra

Check the front display panel circuit board over real good for cracks or breakage. Especially around the mounting fasteners.
 
Nice! I have the Service Manual, I will check the front display panel circuit board with attention and let you know.

Thank you all!
 
Edubra said:
Hi,

I've just bought a MX-1000, it seems to be working fine.....
Click to expand...

Welcome to AK!

Avionic is allways on the money, most likely something shifted during shipping, albeit, it is the first time I see an MX do this.

one question: did you actually listen to some tunes already?

if not,

try to see what AC voltage you have at the terminals..before you connect a set of speakers.

good luck!
 
rottalpha said:
Welcome to AK!

Avionic is allways on the money, most likely something shifted during shipping, albeit, it is the first time I see an MX do this.

one question: did you actually listen to some tunes already?

if not,

try to see what AC voltage you have at the terminals..before you connect a set of speakers.

good luck!
Click to expand...

I will receive it soon,... AC Voltage,...hummnn,..
I will have to check. Thank you.
 
May even be and easier fix.. Check the " Peak Hold" front panel button. See if its engaged.
 
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