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Mx110z selenium rectifier replacement

Mcintosh N said:
I did check again after 3 minutes and ..,
Fantastic!, thanks again
Click to expand...
Looks good! Now that you've done that, you might want to consider re-routing the signal cable from the 6D10 tube. (Hi-lighted in the attached image) I did not have to do this, as my 110 is from 1963.
Might want to start a new thread on this at this point.
Here's a worthwhile thread on the subject:

MX-110Z: A Simple Modification for Reducing Hum

If @monkboughtlunch is anything, he is relentlessly persistent. For nearly 4 years he has contacted me at various times regarding a hum in his MX-110Z, over which time we discussed virtually every aspect of resolving it save throwing the kitchen sink at it. It was particularly problematic when...
audiokarma.org
routing.jpg
 
Just so you know a bad run of selenium rectifiers were installed in C-20's which all failed and started Davie Obrien going out and having Mcintosh amp and pre-amp clinics.
 
Anyone has any idea, the 110z works perfectly except the phono, aux, tuner works nicely but Phono 1 and 2 nothing, I changed the 2 12ax7 from ph1 and 2, and still nothing,
Where should I narrow my search?
Thanks
 
Mcintosh N said:
Anyone has any idea, the 110z works perfectly except the phono, aux, tuner works nicely but Phono 1 and 2 nothing, I changed the 2 12ax7 from ph1 and 2, and still nothing,
Where should I narrow my search?
Thanks
Click to expand...
Make sure the phono 1 and 2 black potentiometers on top of the unit are fully clockwise.
 
Mcintosh N said:
I suspect the two 6u8 are dead, could that be the problem?
Click to expand...
If the tubes are not verified, then yes. Phono 1 and 2 eventually pass through V16 and V17. The tuner passes through V11, so you could tube swap here to see if you get left or right phono.
 
When adding a series resistor after a bridge rectifier what would you suggest as a starter resistor to compensate for added voltage what ohms and watts should I try when first bringing the system to power
 
Hello AK members

Just a silly question but why do you want to replace the selenium bridge by a silicon bridge if it still work perfectly ?
If it is just in case of , this is not the best way to act in my point of view , and the sound will change because the voltage will change with the silicon bridge.(you need to make adaptation in the unit )
There is also a very important fact is that your power transfomer start to be very hot and at least will burn (whatever you are in 120V or 240V)
The most important detail is to realize that the secondary winding in this unit (MX110Z) is direct connected , not fused and if (one day) this selenium bridge start to be bad (not shorted but really bad ) you can not ear it and will destroy this power transformer winding .
The better way in my point of view will be to fuse this winding (high voltage coil ) fuse a fuse of 200mA Fast acting , this way if your selenium bridege is going bad you will see your MX110Z stay in ON but no more sound is produced at the output
This is the proove that your fuse burned because of the bad senium bridge need to replaced at this moment .
I have produced many power transformers for shorted high voltage winding because of the selenium bridge out.

You can leave your comment I am ready to read them
 
While it is
clinic-audio said:
Hello AK members

Just a silly question but why do you want to replace the selenium bridge by a silicon bridge if it still work perfectly ?
If it is just in case of , this is not the best way to act in my point of view , and the sound will change because the voltage will change with the silicon bridge.(you need to make adaptation in the unit )
There is also a very important fact is that your power transfomer start to be very hot and at least will burn (whatever you are in 120V or 240V)
The most important detail is to realize that the secondary winding in this unit (MX110Z) is direct connected , not fused and if (one day) this selenium bridge start to be bad (not shorted but really bad ) you can not ear it and will destroy this power transformer winding .
The better way in my point of view will be to fuse this winding (high voltage coil ) fuse a fuse of 200mA Fast acting , this way if your selenium bridege is going bad you will see your MX110Z stay in ON but no more sound is produced at the output
This is the proove that your fuse burned because of the bad senium bridge need to replaced at this moment .
I have produced many power transformers for shorted high voltage winding because of the selenium bridge out.

You can leave your comment I am ready to read them
Click to expand...
an interesting suggestion and method to keep the seleniums the long term fact is they'll eventually give out and need replacing anyways
 
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