Fisher X-101B Woes ahead.....

Oerets

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Picked up a "As is untested" Fisher X-101B in a convoluted trade a good while ago.
When tested by me there be silence. No humming just plain nothing at all.
Chassis and front panel in great shape. Tested all the tubes to find pretty much all the tubes were bad. The were mostly Fisher tubes loaded.
Replaced with good ones and still no sound.
Really wanting it to sing again and knowing a very qualified nationally known local tube guy give it a look see. Prior to taking it to "Doc" I ordered the cans from Hayseed beforehand.

Well he informed me that BOTH output transformers and the power are bad!
No joy in hearing this. Figured someone powered it on and forgot....

So my question is,
What are my options?
What other models use the same parts?
Look for a donor X-101B?
Give up and sell the parts? This would be the last resort as to the cans are installed along with recapped signal path.....

I will be picking up the unit on Saturday.

Barney
 
Man, that's disappointing. :( I've actually never heard of all the transformers being DOA and would want to do the resistance measurements for myself, just to be sure. It's a tough lesson in showing that checks need to begin with the transformers.

Depending on your needs (do you need a Fisher X-101B or similar?) and what you've got in it, you could get a new PT made up and the OPTs rewound, or keep a lookout for replacements. Why not start with a request for transformers in the Fisher forum to see if anyone can help?

If you don't need another amp and you've not got much in it, part it out. The parts may let another X-101B live another day. It's good that the front panel is clean and crisp.
 
Phew, all the trannies are bad! That's not good news. I'd try to save it but for many that can be a bridge too far.

The experts will come along to help with cross-referencing parts from other models soon. Maybe the X100B/KX100 might have the same or similar parts, but I can't say for sure. You might also want to get a second opinion on the state of the trannies just in case. If they really are all bad you can replace from the big auction site, open and see if the break is accessible/repairable (I saved one OT this way), or get them rebuilt. The experts will point you to who can rebuild them (Heyboer I think). Alternatively, you can look for another parts unit that does have good trannies.

Also, you might get more support by moving this thread to the Fisher section. Lotsa help there.

Also.........

:needpics:
 
Very unusual that a Fisher transformer goes bad. Replacements are out there though, check the auction site or have them re wound... Again, Fisher transformers are very stout. Take the amp to a tech and have it checked. AL
 
Don't go by hear say. Check the outputs with a meter. The power transformer is probably fine as it powers up with no smoke or blown fuses.

I'd be checking the rectifier tube (if it has one) or the diodes or bridge rectifier. Sounds like it is getting no B+.
 
The Tech builds and sells his own brand of tube guitar amps. Has for many years and I trust his judgment.
Yes will double check once the unit is back in my position again.
I will have a more detailed description of issues then. He has been battling health issues so letting him go at a pace comfortable with.

Wanting to know what other units or part number to be on the look out for....

EDIT>>> He did replace the power transformer and was then able to see the other problem manifest.Voltages not right, replace resistors and rewired. Distortion in outputs persists .


Barney
 
I've never heard of so many failures. Although I've resurrected a lot of units that weren't economically viable, I think I'd throw in the towel on this one. I think you'd be much better off finding another one to rebuild, and using this one for parts (front panel; switches; potentiometers; etc.)
 
EDIT>>> He did replace the power transformer and was then able to see the other problem manifest.Voltages not right, replace resistors and rewired. Distortion in outputs persists .
But has he disconnected and measured the resistances of each of the OPTs? Like others who have commented, I wonder if the OPTs are bad--especially now that you report distorted output, rather than no output.

Was there any work done on the amp before you took it to the tech? If so, what? If not, how can you be sure it's the transformers if all the passive components are still original?
 
Barney; Another option. Heyboer may have the X-101-B in their books. Check with them for the Power Transformer and possibly the output's. As for the output's, you can use about any of the transformers that FISHER used on 7591/7868 units. Stay away from the late (serial # 48001 and up) transformer. It's impedance is 10K where it should actually be about 6.8K. The 500c and 800c output's are probably the best for it as they are the largest FISHER had made for 7591 use. Heyboer may even be able to make them too. So that is an option.

If you have or have access to a SAM's Photofact, the power transformer specs are on the sheet, for sections, voltage and amps. It's better if you have this when you call or email them. Turn around is usually about 3 weeks. And their prices are fairly good (certainly better than Transcendar or Edcor or Hammond.)

If you run into any more problems suggest having the thread brought over to the FISHER Forum by an admin.

Make sure that the "DUMMY PLUG" in the center of the unit is actually making contact. If not, no sound. Check the wiring around it underneath. The output coupling caps are squashed in around the drivers, not the output's. It's really tight in there so the smallest physical sized caps you can get in there helps a lot with your sanity, not to mention wire insulation burns, scraped knuckles, and burned fingers. It's one of their better amps IMO, and a good sounding one too. There is a "Phase switch" next to the 5AR4. That's for speaker phasing. DeOxit that one and work the hell out of it. The Phono input's are a bit too close to the outputs and are poorly shielded. Make a sheet metal angle that fits around them from the side wall to the back wall, and solder it in at multiple points. It will lower the phono noise at least 75% (did on mine). See the bottom of page one (1) on this link. Quieted it down quite nicely. http://audiokarma.org/forums/index....q-10khz-phono-squeal-volume-dependent.732992/

Larry
 
All this info will be a great help once the unit is back in my possession. When picking it up will attempt to get a detailed breakdown on issues. Once he called and informed me was giving up much after that was lost in thought of what to do now.

No Sams but an original paper SM on hand.

Yes I agree this would better be if moved to The Fisher forum. Will try and notify the appropriate person.

Plan on getting the unit on Saturday.

Barney
 
Very unusual that a Fisher transformer goes bad. Replacements are out there though, check the auction site or have them re wound... Again, Fisher transformers are very stout. Take the amp to a tech and have it checked. AL

Actually, I have heard the opposite in that there seem to be an unusual number of failures. I can back that up with my own X100B/KX100 output trannie that was bad. I was able to open it and find the break and repair it, but man the wire in them is super fine. No wonder they fail so easily. Do some research and look at what others are reporting on the Fisher tube output trannies - particularly for the integrated amps. I can't speak to the power trannies.
 
My condolences on the bad trannys. I have never had an experience where all of them crapped out. That seems like a one in a million occurrence. Was the unit struck by lightning?
 
My condolences on the bad trannys. I have never had an experience where all of them crapped out. That seems like a one in a million occurrence. Was the unit struck by lightning?


Have no idea as to history of the unit. Came in a multiple trade, told it came from an estate of someone I knew. No history known and was offered as is untested.
I'm in no way going to have a score on this one........ But it happens, just try and not let it happen often!
We will see once I have it back once again.



Barney
 
Hey.......I think Saturday has come and gone, March 2018. How bout an update?


It has been sitting on the shelve since getting it back. The tech who was looking it over and trying to repair passed away around this time. The power transformer was pulled and a generic one installed, then removed wires cut. Old one never wired back up by the tech.
So figure time will lesson the wound some. Started a few times trying to figure out what's what made notes then something shiny catches my attention....
Been busy with other projects and life in general.
 
Hi and thanks for the update. This is very unfortunate that the person who was doing the repair has passed, sorry to read that.
 
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