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 Post subject: Fisher X-100-c amp
PostPosted: Jun Mon 04, 2018 12:04 pm 
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I have a fisher X-100-c amp. The schematic shows two diodes but I only see one in amp.
Could the other be in the transformer. My serial # is in-between the numbers stated on schematic.
Thanks Hunter.


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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Mon 04, 2018 1:59 pm 
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Location: Fernandina Beach, FL
Often, Fisher used a voltage doubler in their power supplies. They are usually silicon and should still be good. The other one should be there.

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Mon 04, 2018 2:08 pm 
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Does the underside look like this? This is a similar model and the diodes are the silver items. Tied together at the terminal strip and one goes to ground; the other one goes to the filter capacitor near the long green resistor.


Attachments:
100C.jpg
100C.jpg [ 63.2 KiB | Viewed 1783 times ]

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Fri 08, 2018 5:39 pm 
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Only have one near Ww resistor.
tried to insert pic but wouldn't let me do it


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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Fri 08, 2018 6:07 pm 
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I'll try to insert pic when I get home. One thing I noticed from your pic and mine is that I have 3 bias pots where you only have two.
My diode is on a terminal strip and connects from wire wound resistor to the capacitor which I believe is C28 .01


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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Fri 08, 2018 6:58 pm 
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Don't get hung up on the picture. It is a different but similar model. I was only showing that it had two diodes. When you get a picture up, hopefully one of us can help. We would like to be of assistance.

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Fri 08, 2018 7:15 pm 
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Joined: May Sat 06, 2006 4:03 am
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Location: ZIP 23831 South of Richmond, VA 25 miles down the pike.
Here's couple pictures of x-100-c I used to have.

Bill J.


Attachments:
FISHER X-100-C 01.JPG
FISHER X-100-C 01.JPG [ 208.49 KiB | Viewed 1682 times ]
FISHER X-100-C 12.JPG
FISHER X-100-C 12.JPG [ 251.75 KiB | Viewed 1682 times ]
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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Fri 08, 2018 7:29 pm 
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NumberMaj 1 wrote:
Here's couple pictures of x-100-c I used to have.

Bill J.

Bill, thanks for the photos, that should help the original poster. I see two diodes.


Attachments:
FISHER X-100-C 12.JPG
FISHER X-100-C 12.JPG [ 252.05 KiB | Viewed 1680 times ]

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Sat 09, 2018 3:25 am 
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[img]C:\Users\hunter\Pictures\Saved%20Pictures[/img]

This my x-100-c. My Dad owned an Electronics shop where he worked on Radar. He sold and installed high end Fisher receivers and amplifiers on the side. This one was installed in my cousins house. Cuz gave it to me later on. So I feel the amp has never been worked on. Looks like the wire wound resistor has gotten a little hot. I turned it on and was able to here music albeit volume was a little low. I don't see the diode that goes to ground. Thanks for the help.


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IMG_3389.JPG
IMG_3389.JPG [ 171.33 KiB | Viewed 1668 times ]
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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Sat 09, 2018 12:55 pm 
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Interesting...

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Sun 10, 2018 3:01 am 
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Did you try to de-oxidize the rocker switches or just left them as is?? Mine look the same.
I'm wanting to correctly install the new yellow axial capacitors with the foil side
oriented in the right direction but first I have to build the checker. Most of my
parts have come in. Do you take the time to find the foil side to your capacitors??
Guess I'll have to make a decision on the diode when the time comes. Hehehe.
Thanks.


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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Mon 11, 2018 3:09 am 
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AntiquePaperboy wrote:
[img]C:\Users\hunter\Pictures\Saved%20Pictures[/img]

This my x-100-c. My Dad owned an Electronics shop where he worked on Radar. He sold and installed high end Fisher receivers and amplifiers on the side. This one was installed in my cousins house. Cuz gave it to me later on. So I feel the amp has never been worked on. Looks like the wire wound resistor has gotten a little hot. I turned it on and was able to here music albeit volume was a little low. I don't see the diode that goes to ground. Thanks for the help.


I wouldn't be so sure. That giant wirewound resistor is definitely NOT stock. Something's very strange there. The large cap has an insulator, (which you would expect in a doubler setup) but then its can has been grounded to the chassis. I'm pretty sure this thing has been modded somewhere along the way. And it definitely should have 2 diodes.

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Mon 11, 2018 1:40 pm 
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AntiquePaperboy wrote:
...Do you take the time to find the foil side to your capacitors??
Guess I'll have to make a decision on the diode when the time comes. Hehehe. Thanks.

Capacitors manufactured today do not have an outer foil marker because it really doesn't matter. You can install them either way.

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Mon 11, 2018 3:38 pm 
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Don Cavey wrote:
AntiquePaperboy wrote:
...Do you take the time to find the foil side to your capacitors??
Guess I'll have to make a decision on the diode when the time comes. Hehehe. Thanks.

Capacitors manufactured today do not have an outer foil marker because it really doesn't matter. You can install them either way.


Don..I think he's referring to this youtube video: https://www.youtube.com/watch?v=BnR_DLd1PDI&t=1s. The author of the video may have a point, but the real world impact of this is highly questionable. The owner of the amp would be much better off first figuring out why someone pulled out one of the diodes and rewired the power supply.

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Antique Radio Club of Illinois


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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Tue 12, 2018 12:22 pm 
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jmsent wrote:
Don Cavey wrote:
AntiquePaperboy wrote:
...Do you take the time to find the foil side to your capacitors??
Guess I'll have to make a decision on the diode when the time comes. Hehehe. Thanks.

Capacitors manufactured today do not have an outer foil marker because it really doesn't matter. You can install them either way.


Don..I think he's referring to this youtube video: https://www.youtube.com/watch?v=BnR_DLd1PDI&t=1s. The author of the video may have a point, but the real world impact of this is highly questionable. The owner of the amp would be much better off first figuring out why someone pulled out one of the diodes and rewired the power supply.

John, I am sure that you are correct on every account. Thanks for your comment.

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Tue 12, 2018 6:09 pm 
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In response to the wire wound(R65) I believe mine says dale on it so It might be original, not sure let me look again. I'm talking about the one near the diodes. Now on the other side of the chassis I see what I believe to be a brown glass high watt resistor. Looking at another pic of an x-100-c, not just the ones above, there looks like a capacitor might need to go along with that high watt resistor. What I need to do first is parts recognition, find out what goes where, and find out what needs to go and what needs to be put back in. When I put the diode(CR2) in I was thinking of connecting to the ground of C28 .01 uf. Thanks guys, I'll know more when I get home.


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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Tue 12, 2018 10:42 pm 
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AntiquePaperboy wrote:
In response to the wire wound(R65) I believe mine says dale on it so It might be original, not sure let me look again. I'm talking about the one near the diodes. Now on the other side of the chassis I see what I believe to be a brown glass high watt resistor. Looking at another pic of an x-100-c, not just the ones above, there looks like a capacitor might need to go along with that high watt resistor. What I need to do first is parts recognition, find out what goes where, and find out what needs to go and what needs to be put back in. When I put the diode(CR2) in I was thinking of connecting to the ground of C28 .01 uf. Thanks guys, I'll know more when I get home.


You need to look at the wiring for that entire power supply, especially around that single section electrolytic can. The outer tabs should not ground to the chassis. I also suspect that one of the electrolytic capacitors may have gone south or a diode shorted, and that this mod that was done may have been a shortcut to get the amplifier limping along. You can certainly use Don's photo as a reference, as his is wired correctly. As for the big brown resistor, given one side is connected to ground, I'm guessing it's not part of the power supply circuit. It may be a replacement for R61 or R62 which is part of the speaker circuit. You've got a job ahead of you there! Nothing worse than a piece of gear that's been modded like this. You should be able to get it back to stock, but I'm hoping you've included new filter caps in your rebuild.

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Antique Radio Club of Illinois


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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Wed 13, 2018 12:09 am 
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jmsent wrote:
... I also suspect that one of the electrolytic capacitors may have gone south or a diode shorted, and that this mod that was done may have been a shortcut to get the amplifier limping along. You can certainly use Don's photo as a reference, as his is wired correctly. As for the big brown resistor, given one side is connected to ground, I'm guessing it's not part of the power supply circuit. It may be a replacement for R61 or R62 which is part of the speaker circuit. You've got a job ahead of you there! Nothing worse than a piece of gear that's been modded like this. You should be able to get it back to stock, but I'm hoping you've included new filter caps in your rebuild.


The more I read this thread, the more I agree. It looks like someone jacklegged it just to get it back "working". Certainly you know that Fisher designed it correctly and if you were to put back the parts that are supposed to be there, connected as they should be, you may be back in business. That amplifier is too nice to suffer this mangling (if that is what has happened).

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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Mon 18, 2018 6:37 pm 
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Thanks. Any chance posting a picture of the underside chassis opposite side of the one shown above. I believe I'm missing C29 100 micro farad electrolytic which ties in with R76 500 ohm ceramic resistor. Thanks. Still plugging away.


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 Post subject: Re: Fisher X-100-c amp
PostPosted: Jun Tue 19, 2018 2:41 am 
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Joined: May Sat 06, 2006 4:03 am
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Location: ZIP 23831 South of Richmond, VA 25 miles down the pike.
More pictures.

Bill J.


Attachments:
FISHER X-100-C 06.JPG
FISHER X-100-C 06.JPG [ 222.46 KiB | Viewed 1419 times ]
FISHER X-100-C 07.JPG
FISHER X-100-C 07.JPG [ 247.68 KiB | Viewed 1419 times ]
FISHER X-100-C 08.JPG
FISHER X-100-C 08.JPG [ 252.88 KiB | Viewed 1419 times ]
FISHER X-100-C 09.JPG
FISHER X-100-C 09.JPG [ 250.35 KiB | Viewed 1419 times ]
FISHER X-100-C 10.JPG
FISHER X-100-C 10.JPG [ 249.46 KiB | Viewed 1419 times ]
FISHER X-100-C 11.JPG
FISHER X-100-C 11.JPG [ 244.39 KiB | Viewed 1419 times ]
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