funkenaround
Active Member
thanks for the tip info!
Mc2155 Output Driver Help
- Thread starter funkenaround
- Start date
clinic-audio
all on YAMAHA untill 1990
You are playing a game that I don't play !
Using a "touched" driver board on a working channel is the best way to damage the output section of this (previous working) channel !
I don't undertand why your meter will be " maybe toast" !
It is too bad to touch this kind of unit with the necessary knowledge for that !
I hope that you will be successfull in your investigations :scratch2:
funkenaround
Active Member
gonna look at it again tomorrow
move it from the carpet to the table top
move it from the carpet to the table top
Last edited:
funkenaround
Active Member
although I haven't really had much time to give to the amp this week, I have been in contact with Mcintosh for the replacement bits
I spoke with digikey, searcherd mouser and some others, too much of a pain in the as for some small bits
as I was about to order from mac, they informed me of a NO DROP SHIP policy so that f'd up my plans on that order
Yesterday I figured if all I couldn't get readily at my local supplier was the NSDu57/NTE50 , then I would get the caps and the last transistor I did from them and see how things turned out
well last night I soldered in the 2 caps and installed the 132-203/nte280 and put the beast back together
held my breath and voila---no real improvement other than the left channel had some audible garble/distortion/no amplification
before I lay my head I thought I would do the unthinkable as I have before, SWAP DRIVE BOARDS!!!!!!!!!!!! SCARY!!!!!!!!!!!
so I just did and voila the "AFFECTED" "WORKED ON BOARD" drives the right channel beautifully now
so I have achieved some great information here, the issue now resides outside of the board
this being said, and I have replaced all the power and transistors in the heat sink for the left channel except for 132-204 which tested identical to the one in the right channel, where else can my issue be arising from?
anybody?
I spoke with digikey, searcherd mouser and some others, too much of a pain in the as for some small bits
as I was about to order from mac, they informed me of a NO DROP SHIP policy so that f'd up my plans on that order
Yesterday I figured if all I couldn't get readily at my local supplier was the NSDu57/NTE50 , then I would get the caps and the last transistor I did from them and see how things turned out
well last night I soldered in the 2 caps and installed the 132-203/nte280 and put the beast back together
held my breath and voila---no real improvement other than the left channel had some audible garble/distortion/no amplification
before I lay my head I thought I would do the unthinkable as I have before, SWAP DRIVE BOARDS!!!!!!!!!!!! SCARY!!!!!!!!!!!
so I just did and voila the "AFFECTED" "WORKED ON BOARD" drives the right channel beautifully now
so I have achieved some great information here, the issue now resides outside of the board
this being said, and I have replaced all the power and transistors in the heat sink for the left channel except for 132-204 which tested identical to the one in the right channel, where else can my issue be arising from?
anybody?
clinic-audio
all on YAMAHA untill 1990
Hello
Many questions to ask :
-did you replace the bias TR 132090 ?
-did you check or replace the fuse resistor in the heatsink 22 OHM Fire proof type ?
- did you check with an accurate meter all the emiter resistors ( non inductive type) ?
waiting for your report
Many questions to ask :
-did you replace the bias TR 132090 ?
-did you check or replace the fuse resistor in the heatsink 22 OHM Fire proof type ?
- did you check with an accurate meter all the emiter resistors ( non inductive type) ?
waiting for your report
funkenaround
Active Member
132-090 yes
Fuse resistor checked and appeared OK
Using an analog meter, I trust it
Fuse resistor checked and appeared OK
Using an analog meter, I trust it
kevzep
Its all about the Music
Test all the emitter resistors and output transistors......
funkenaround
Active Member
I've replaced all the transistors but one and that one tests identically to the same as in the right channel
I didn't test the transistor resistors, I thought and forgot
I will pop out the heatsink again and check
What is the function on the fuse resistor?
Is this the one that is riveted to the heatsink?
Ty
I didn't test the transistor resistors, I thought and forgot
I will pop out the heatsink again and check
What is the function on the fuse resistor?
Is this the one that is riveted to the heatsink?
Ty
funkenaround
Active Member
removed the heatsink to investigate the emitter resistors
if both my analog and digital meters are correct, all 4 of the resistors are toast
all 4 open circuit
if this is the case and it seems to be, then tomorrow I'll have the amp up and running
I thought and meant to test them before putting the sink back in last night, just didn't, all I was thinking about was whether the networking adapter I installed in my sailboat yesterday would have all the electronics talking to each other, and today they did
anyhow, will pick up some resistors in the morning, install them and report hopefully of positive results
if both my analog and digital meters are correct, all 4 of the resistors are toast
all 4 open circuit
if this is the case and it seems to be, then tomorrow I'll have the amp up and running
I thought and meant to test them before putting the sink back in last night, just didn't, all I was thinking about was whether the networking adapter I installed in my sailboat yesterday would have all the electronics talking to each other, and today they did
anyhow, will pick up some resistors in the morning, install them and report hopefully of positive results
funkenaround
Active Member
Was just at the electronics supplier for the emiter resistors
Apparently 5watt .15 ohm is not common and they have none
I made a trip down the road to a very high end parts supplier and they have the resistors,
But they are different style , not the classic ceramic/sandcast rectangular , but they have the ppill type that resembles more of a cap
Is their any concern with devaluing ??? The replacement j can get is of superior quality
While I was there, I had the teck check the sample I had and indeed its pooched as will be the other three
New resistor or stick with the classic past???
Apparently 5watt .15 ohm is not common and they have none
I made a trip down the road to a very high end parts supplier and they have the resistors,
But they are different style , not the classic ceramic/sandcast rectangular , but they have the ppill type that resembles more of a cap
Is their any concern with devaluing ??? The replacement j can get is of superior quality
While I was there, I had the teck check the sample I had and indeed its pooched as will be the other three
New resistor or stick with the classic past???
funkenaround
Active Member
executive decision made
out with old school and in with 1% high quality new school
out with old school and in with 1% high quality new school
funkenaround
Active Member
just installed the resistors and have both good and bad news to report
good news:
once the heat sink was connected back and the amp powered on, both channels operating
bad news:
after a minute or two the channel in question cutout, I nearly had a coronary!
the heat sink was super hot----something is not right here
must pull the heat sink check and see if anything is blown, visually there aren't any exploded transistors, resistors or capacitors
any ideas?
good news:
once the heat sink was connected back and the amp powered on, both channels operating
bad news:
after a minute or two the channel in question cutout, I nearly had a coronary!
the heat sink was super hot----something is not right here
must pull the heat sink check and see if anything is blown, visually there aren't any exploded transistors, resistors or capacitors
any ideas?
kevzep
Its all about the Music
Did you set the bias?
You have replaced semiconductors in the output section and other components critical in the current flow of said output section, so you need to return the bias setting to zero, and go through the procedure in the manual for setting quiescent current.
The thermal cutout would have shut it down.....
You are playing with fire here just flicking the switch without checking all this.
It takes microseconds for things to go bad and take out all the hard work you have just done......
funkenaround
Active Member
I'm a little grasshopper
Just did some reading on the bias setting
wish I new beforehand,
the bias adjust is on the driver board, the two blue adjusting pots, correct?
need some guidance on procedure and voltages
thanks much!
Just did some reading on the bias setting
wish I new beforehand,
the bias adjust is on the driver board, the two blue adjusting pots, correct?
need some guidance on procedure and voltages
thanks much!
clinic-audio
all on YAMAHA untill 1990
must pull the heat sink check and see if anything is blown, visually there aren't any exploded transistors, resistors or capacitors
any ideas?
As you don't follow my advise , we are now in front of one amplifier with x components inside but no more a MCINTOSH
I have explain you to buy original spare parts to avoid any problem , you don't mind and buy the first resistor you found .
I explain you to use 0,15 ohm non inductive resistor . You buy a resistor with 1% , yes but not dedicated for this application .
You know why your heatsink is very hot now .
I do perfect service MCINTOSH since 35 years and never use cheap components for refix hem .
Again , do what you want , this is your unit but is it necessary to spend more time to help you if you don't care about what we told you to do .
:thumbsdn:
any ideas?
As you don't follow my advise , we are now in front of one amplifier with x components inside but no more a MCINTOSH
I have explain you to buy original spare parts to avoid any problem , you don't mind and buy the first resistor you found .
I explain you to use 0,15 ohm non inductive resistor . You buy a resistor with 1% , yes but not dedicated for this application .
You know why your heatsink is very hot now .
I do perfect service MCINTOSH since 35 years and never use cheap components for refix hem .
Again , do what you want , this is your unit but is it necessary to spend more time to help you if you don't care about what we told you to do .
:thumbsdn:
kevzep
Its all about the Music
Get the service manual and follow the instructions. I dont have the manual for this amplifier, so I can't help you with that.
But Yes, since the amplifier shut down you will have to go through and check everything again......
The emitter resistors need to be Non inductance, VERY important.
I'm not sure why you keep going for the most convenient and cheapest fix, its false economy, because you will have these problems if you keep going like this.
Just get the right parts and wait for them to turn up, and while you are waiting, get the service manual and when everything arrives, you can put it together and have it working first time.
funkenaround
Active Member
yes, I got NON INDUCTIVE resistors.......
Mcintosh wasn't any help to me, no big deal
I've got all that I need
NOBODY MENTIONED BIASING
now whats more important, biasing or buying Mcintosh, Mouser or Digikey direct?
what I've purchased has been of equal or SUPERIOR quality to the original
I'll figure out the biasing on my own
it ain't rocket science, I've done it before on my tube amps, just dont know where to take the reading from,
Mcintosh wasn't any help to me, no big deal
I've got all that I need
NOBODY MENTIONED BIASING
now whats more important, biasing or buying Mcintosh, Mouser or Digikey direct?
what I've purchased has been of equal or SUPERIOR quality to the original
I'll figure out the biasing on my own
it ain't rocket science, I've done it before on my tube amps, just dont know where to take the reading from,
clinic-audio
all on YAMAHA untill 1990
NOBODY MENTIONED BIASING
Yes, because biasing is the last step ! we adjust bias once everything works !
You will not be able to adjust bias because the components you have choosen are not appropriate .
But if you think that any kind of resistor (of the same value) will fit and all transistor will work the same , I have nothing more to explain ...
Yes, because biasing is the last step ! we adjust bias once everything works !
You will not be able to adjust bias because the components you have choosen are not appropriate .
But if you think that any kind of resistor (of the same value) will fit and all transistor will work the same , I have nothing more to explain ...
funkenaround
Active Member
who said I used cheap components or the first I found????
read as I have written
1% tolerance v.s 5% tolerance that Mcintosh used at the factory
the spec is same .15 ohm 5 watt
what the heck are you saying here? I put cheap crap in this amp??
I say 5% tolerance is CHEAP CRAP! and that's what Mac used
I respect what you guys say, but you have to read what I say and not put words in my mouth, I may go about things haphazardly, but I haven't put one cheapy part in
If re Biasing is necessary, then that indication would have been nice before I fired it up again
and by the way , Mcintosh doesn't make transistors, resistors, etc, they are outsourced,
so if you feel the need to buy your battery or oil from your local VW, BMW, MB, or Volvo dealer, then go right ahead
I appreciate the help, but I don't need to be bashed because I didn't buy factory direct
so can I get some help on biasing? I read it in the Mcintosh service manual, I know the procedure, just not the test points
peace
read as I have written
1% tolerance v.s 5% tolerance that Mcintosh used at the factory
the spec is same .15 ohm 5 watt
what the heck are you saying here? I put cheap crap in this amp??
I say 5% tolerance is CHEAP CRAP! and that's what Mac used
I respect what you guys say, but you have to read what I say and not put words in my mouth, I may go about things haphazardly, but I haven't put one cheapy part in
If re Biasing is necessary, then that indication would have been nice before I fired it up again
and by the way , Mcintosh doesn't make transistors, resistors, etc, they are outsourced,
so if you feel the need to buy your battery or oil from your local VW, BMW, MB, or Volvo dealer, then go right ahead
I appreciate the help, but I don't need to be bashed because I didn't buy factory direct
so can I get some help on biasing? I read it in the Mcintosh service manual, I know the procedure, just not the test points
peace
clinic-audio
all on YAMAHA untill 1990
who said I used cheap components or the first I found????
This is what I feel when I read your words
1% tolerance v.s 5% tolerance that Mcintosh used at the factory
Sorry but this is not a problem of tolerance
the spec is same .15 ohm 5 watt NO ! that's your reason of your problem ! this is not a rocket science but your rocket will not work !
I say NON INDUCTIVE this is not without specific reason . I advise you to buy original (like for transistors) because you will save time and money (your amp will work immediately )
You will not spend a week (or more ) to find a place where these resistors are available that's why buying original is more fast and SAFE
If re Biasing is necessary, then that indication would have been nice before I fired it up again
You will not be successfull with the wrong resistors your amp will oscillate and draw too much current and bias will not be ajustable ,that why your heatsink goes very very hot and make your thermal protection working (lucky man you are )
and by the way , Mcintosh doesn't make transistors, resistors, etc, they are outsourced,
this is right but there is something that you don't know , MCINTOSH is not the only manufacturer to use sorted components or sorted semi-conductors .
If you replace original (damaged) transistor by one of radioshack you have 95% probability this will not work like it should because it is not sorted and for example the Beta is not the same at all !
Try to use 1N4148 coming from your local dealer in one Audio Resarch instead the original diode , your AR will not work at all because AR make specific sort for their semi-conductors !
This is not a rocket science but it is not the mess where any component will be fine ...
And last very important point : do you know why MCINTOSH use their own mark on transistors ?
This is to avoid you to use any other output transistor not sorted not selected who will make your favorite amp not working for a long time !
I appreciate the help, but I don't need to be bashed because I didn't buy factory direct
I wanted to help you by indicating you the right way to act . I don't mind that you buy direct a the factory or not this is not my amp and this is your money . I don't have any money in MCINTOSH Lab but it was the fastest and safe solution to your trouble .
so can I get some help on biasing? I read it in the Mcintosh service manual, I know the procedure, just not the test points
Change your resistors and then, you will be able to bias your amp , I am sure .
This is what I feel when I read your words
1% tolerance v.s 5% tolerance that Mcintosh used at the factory
Sorry but this is not a problem of tolerance
the spec is same .15 ohm 5 watt NO ! that's your reason of your problem ! this is not a rocket science but your rocket will not work !
I say NON INDUCTIVE this is not without specific reason . I advise you to buy original (like for transistors) because you will save time and money (your amp will work immediately )
You will not spend a week (or more ) to find a place where these resistors are available that's why buying original is more fast and SAFE
If re Biasing is necessary, then that indication would have been nice before I fired it up again
You will not be successfull with the wrong resistors your amp will oscillate and draw too much current and bias will not be ajustable ,that why your heatsink goes very very hot and make your thermal protection working (lucky man you are )
and by the way , Mcintosh doesn't make transistors, resistors, etc, they are outsourced,
this is right but there is something that you don't know , MCINTOSH is not the only manufacturer to use sorted components or sorted semi-conductors .
If you replace original (damaged) transistor by one of radioshack you have 95% probability this will not work like it should because it is not sorted and for example the Beta is not the same at all !
Try to use 1N4148 coming from your local dealer in one Audio Resarch instead the original diode , your AR will not work at all because AR make specific sort for their semi-conductors !
This is not a rocket science but it is not the mess where any component will be fine ...
And last very important point : do you know why MCINTOSH use their own mark on transistors ?
This is to avoid you to use any other output transistor not sorted not selected who will make your favorite amp not working for a long time !
I appreciate the help, but I don't need to be bashed because I didn't buy factory direct
I wanted to help you by indicating you the right way to act . I don't mind that you buy direct a the factory or not this is not my amp and this is your money . I don't have any money in MCINTOSH Lab but it was the fastest and safe solution to your trouble .
so can I get some help on biasing? I read it in the Mcintosh service manual, I know the procedure, just not the test points
Change your resistors and then, you will be able to bias your amp , I am sure .