Fisher repair in NYC?

Mine was a 12pk of Coca-Cola. In this case the Bronx is a hell of a lot easier on the feet and your backsides than Baltimore is. Go see George. He'll get it figured out.

Wonder if he's got a mismatched quad, or the drivers are just plain worn out. I ran that video at least 10 times and couldn't see any flickering. Lemme turn out the lights in here and watch it again with the audio all th way up on the flat screen TV I'm using as a monitor
 
notdigital said:
Pat:

My bench fee is a 6 pack. Assuming you're willing to hike it to the Bronx I'll take a looksee. I'm gonna be home the 1st 2 weeks in February. If you can work out a day other than the weekend to stop by I'll be happy to check it out for you. Figure on more beer and sushi as your final cost if it leaves my place fixed.

Geo
Click to expand...


George,

Thanks for the kind offer. I am happy to hit up the Bronx and have a little flexibility on times. I will pm you my cell and you can tell me your favorite beer. Much appreciated and thank you.

P
 
larryderouin said:
Mine was a 12pk of Coca-Cola. In this case the Bronx is a hell of a lot easier on the feet and your backsides than Baltimore is. Go see George. He'll get it figured out.

Wonder if he's got a mismatched quad, or the drivers are just plain worn out. I ran that video at least 10 times and couldn't see any flickering. Lemme turn out the lights in here and watch it again with the audio all th way up on the flat screen TV I'm using as a monitor
Click to expand...

Thanks for the offer Larry.

I wonder if youtube down grades the video quality. I will upload another video that I think shows it better.

Thanks!
 
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Patrick -- Unfortunately, there is a strong chance that the output transformer for the problematic channel is bad. You can confirm this by measuring the voltage at pin #9 of both inboard power tubes, which are the ones flickering. Normally, there should be around 400 vdc or more on these pins. If it is missing on one of the tubes (or extremely low compared to the other tube), then you've got your answer. Hopefully you can check this and let us know!

Dave
 
I
dcgillespie said:
Patrick -- Unfortunately, there is a strong chance that the output transformer for the problematic channel is bad. You can confirm this by measuring the voltage at pin #9 of both inboard power tubes, which are the ones flickering. Normally, there should be around 400 vdc or more on these pins. If it is missing on one of the tubes (or extremely low compared to the other tube), then you've got your answer. Hopefully you can check this and let us know!

Dave
Click to expand...


Dave, thanks for the info.

Like I said, I am a neophyte. How should I measure this? Rather my question is where would I place my positive and negative leads on the multimeter. Secondly what would be the dial setting I should put my multimeter on? 500v on the DCV?

Thanks!
 
Patrick_W said:
I



Dave, thanks for the info.

Like I said, I am a neophyte. How should I measure this? Rather my question is where would I place my positive and negative leads on the multimeter. Secondly what would be the dial setting I should put my multimeter on? 500v on the DCV?

Thanks!
Click to expand...
Patrick,

Correct, DC scale Neg lead to chassis ground.
 
Patrick_W said:
I am assuming, tubes out and positive in the hole where the 9 pin on the tube would go. Correct?
Click to expand...
No. Test with tubes in. You will need to remove bottom plate and turn the unit upside down. Pins are all numbered. Numbering is clockwise. Use small alligator clips on your tester leads to prevent mishap accident. Take your time and be safe
 
grindfix said:
No. Test with tubes in. You will need to remove bottom plate and turn the unit upside down. Pins are all numbered. Numbering is clockwise. Use small alligator clips on your tester leads to prevent mishap accident. Take your time and be safe
Click to expand...

Now that wasn't so hard....

Thanks for the detailed instructions.

V9 reads a steady 464.

V10 I get nothing. Zero. No reading whatsoever on the multi.

I have my answer it seems.
 
Patrick -- I was sorry to be the bearer of the potentially bad news, but that model has a history of output transformers letting go. The good news is that because of that, there are often "mates" for sale on the auction site - or Transcendar might just offer an exact clone of the original as well. Always to disheartening to loose a transformer, but it doesn't mean that the unit cannot be fixed -- just that it will take more resolve to achieve that end.

Good luck with it!

Dave
 
dcgillespie said:
Patrick -- I was sorry to be the bearer of the potentially bad news, but that model has a history of output transformers letting go. The good news is that because of that, there are often "mates" for sale on the auction site - or Transcendar might just offer an exact clone of the original as well. Always to disheartening to loose a transformer, but it doesn't mean that the unit cannot be fixed -- just that it will take more resolve to achieve that end.

Good luck with it!

Dave
Click to expand...


Dave,

Thanks for the analysis. I am going to see what can be done. I appreciate the efforts by all on this evolving saga.

Best,

Patrick
 
dcgillespie said:
Patrick -- I was sorry to be the bearer of the potentially bad news, but that model has a history of output transformers letting go. The good news is that because of that, there are often "mates" for sale on the auction site - or Transcendar might just offer an exact clone of the original as well. Always to disheartening to loose a transformer, but it doesn't mean that the unit cannot be fixed -- just that it will take more resolve to achieve that end.

Good luck with it!

Dave
Click to expand...


One more question. Will any of the X-100 series of transformers work? I should try to find documentation for this kit.

Thanks!
 
As a general rule, almost any Fisher output transformer that came from a unit that used either 7868 or 7591 tubes, and will physically fit and mount up acceptably will work. There are always slight changes that might need to be made to accommodate a different transformer, but they are usually minor compared to physically fitting a different transformer to begin with. The thing to watch out for when trying a transformer from the same model series but different version of the model, is that many of Fisher's units started out with smaller output tubes (6BQ5/7189), and then as the model evolved, it changed into using the bigger 7868/7591 output tubes. The X-101 and X-202 series certainly did this, and I believe that the X-100 series did as well.

Dave
 
Patrick;
All of these amps use 7591 or 7868 output tubes.
X-100-b
X-101-b
X-101-c
X-101-d
X-200
X-202-b
X-202-c



If I'm reading Dave right, you could conceivably use the transformers from a 400, 500/800B or 500/800C.

Larry
 
Last edited:
dcgillespie said:
As a general rule, almost any Fisher output transformer that came from a unit that used either 7868 or 7591 tubes, and will physically fit and mount up acceptably will work. There are always slight changes that might need to be made to accommodate a different transformer, but they are usually minor compared to physically fitting a different transformer to begin with. The thing to watch out for when trying a transformer from the same model series but different version of the model, is that many of Fisher's units started out with smaller output tubes (6BQ5/7189), and then as the model evolved, it changed into using the bigger 7868/7591 output tubes. The X-101 and X-202 series certainly did this, and I believe that the X-100 series did as well.

Dave
Click to expand...

The notation on my transformers is T849-116-5B and the one I need is T849-116-6B.

That makes complete sense. I will look for a transformer that uses the same types of power tubes. I know that a Fisher 400 uses the same 7868 tubes so that certainly opens up the possibility.

It seems for newly manufactured transformers I would have to go with the Transcendar transformers you mentioned. Although I don't see them for sale anywhere.
 
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