Proton am-30

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Hi Antonello,

Attached is a schematics not exactly AM-30's but close to it. In red the actual designation and type of transistors of AM-30's.
Mine had the right channel blown. I fixed it by changing output transistors and their drivers and Q509 too.
Note that I replaced output transistors 2SC3281 and 2SA1302 by MJL3281 and MJL1302 and it works fine.
You said you always burnt a driver; make sure to replace insulating stuff as the driver heatsink can get in contact with the main heatsink.

Before powering on the amp, try to disconnect the final stage power (unplug the connector the closest to the main heatsink), power on it and check the various voltages. You can compare with the other channel voltages. This check can help you find issues with less risk to blown again the final stages. If this check looks correct, plug again the connector and cross the fingers ;)

Laurent.
 

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Hi Antonello,

Attached is a schematics not exactly AM-30's but close to it. In red the actual designation and type of transistors of AM-30's.
Mine had the right channel blown. I fixed it by changing output transistors and their drivers and Q509 too.
Note that I replaced output transistors 2SC3281 and 2SA1302 by MJL3281 and MJL1302 and it works fine.
You said you always burnt a driver; make sure to replace insulating stuff as the driver heatsink can get in contact with the main heatsink.

Before powering on the amp, try to disconnect the final stage power (unplug the connector the closest to the main heatsink), power on it and check the various voltages. You can compare with the other channel voltages. This check can help you find issues with less risk to blown again the final stages. If this check looks correct, plug again the connector and cross the fingers ;)

Laurent.
_________________________________________________________________


Hello thanks for the pattern just saw him today
but in between I had already burned more transistors ..
Cable ... not foot the first time that this had a hand I found the 2 MJL 21194/21193 short equity and its drivers
I replaced them and it worked well ... then in an Italian forum, but one said that the transistors were not so original tarot
So I ordered them from milano (I live in Sardinia) I get them to return and this time I'm in this mess
wrong position of the first pilots
Then I did not realize that a transistor was shorted
Last time I burned because the transistors were wrong position
Once again I am blown because I forgot the mica insulation
I finally found myself with no more spare parts and are still at a standstill
I also replaced the various bc 550/556 / and more ... I checked the resistors and diodes, comparing them with the good channel ... I also replaced the trimmer with the same value of what is working in the channel ...
but I have not solved ...
Now I have to go to Rome for the holidays when we return to meddle ...
Thanks Laurent for the scheme
Antonello
 
Hi Antonello,

Attached is a schematics not exactly AM-30's but close to it. In red the actual designation and type of transistors of AM-30's.
Mine had the right channel blown. I fixed it by changing output transistors and their drivers and Q509 too.
Note that I replaced output transistors 2SC3281 and 2SA1302 by MJL3281 and MJL1302 and it works fine.
You said you always burnt a driver; make sure to replace insulating stuff as the driver heatsink can get in contact with the main heatsink.

Before powering on the amp, try to disconnect the final stage power (unplug the connector the closest to the main heatsink), power on it and check the various voltages. You can compare with the other channel voltages. This check can help you find issues with less risk to blown again the final stages. If this check looks correct, plug again the connector and cross the fingers ;)

Laurent.

_____________________________
Hello thanks for the pattern just saw him today
but in between I had already burned more transistors ..
Cable ... not foot the first time that this had a hand I found the 2 MJL 21194/21193 short equity and its drivers
I replaced them and it worked well ... then in an Italian forum, but one said that the transistors were not so original tarot
So I ordered them from milano (I live in Sardinia) I get them to return and this time I'm in this mess
wrong position of the first pilots
Then I did not realize that a transistor was shorted
Last time I burned because the transistors were wrong position
Once again I am blown because I forgot the mica insulation
I finally found myself with no more spare parts and are still at a standstill
I also replaced the various bc 550/556 / and more ... I checked the resistors and diodes, comparing them with the good channel ... I also replaced the trimmer with the same value of what is working in the channel ...
but I have not solved ...
Now I have to go to Rome for the holidays when we return to meddle ...
Thanks Laurent for the scheme
Antonello
 
Hello,

I received a Proton AM-30 today but I burnt two resistors when I turned on the power.
White smoke! Section Q510,resistors R532/RX2 (?).these are totally blown up.
I also saw some transparent/yellow-ish liquid on the base of two little capacitors. Could it be glue? (which I doubt of because of the well finished work on this cardboard) Maybe a leak?
I'm not so good at electronic,so I dont know if I could do it on my own.
Maybe I could find the resistors/capa values on the scheme and replace them.
Any advice would be welcome,since there is not much data on this amp on the web.

Thanks
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.