Another Fisher 800B Rebuild

**Warning - extremely long personal recounting of the 50 year history of a Fisher 800B - Read at your own risk!**

I have just embarked on the rebuild of my 800B. This one is special to me since it was originally purchased new by my uncle back in 1963. He purchased the 800B along with a Thorens TD124 TT with SME3009 arm, Tandberg Reel to Reel and Wharfedale W70 speakers. Sadly, only the Fisher 800B remains since the rest of the gear was lost to Katrina on the gulf coast. (I'll get to that in a minute.)
This Fisher has always been part of my life. Having owned this terrific system for a couple of years back in the early 1960's, my uncle took a job working for NASA at a satellite tracking station in Madrid. He left the system in my parent's care and it sat in our formal dining room for years. My parents never appreciated music very much, so I often snuck into the formal dining room and played the set - I remember being 6 years old and walking up the Fisher and turning it on - the stereo beam tubes would slowly light up and converge - as if the stereo was waking up (that's what it looked like to a six year old, anyway.) I sat and played my parent's records many times - The Ink Spots, the Goldfinger movie soundtrack (with Shirley Bassey) and the the movie soundtrack from 2001:A Space Odyssey. Definitely some strange music for a grade schooler!

Anyway, fast forward ten years to me becoming a teenager - my uncle had stayed living in Europe for many years and returned to live in Colorado. He wasn't interested in getting the system back, so I was able to take it and move it into my bedroom. I was fourteen and had this Fisher/Thorens/Tandberg/Warfedale system - to most folks back in 1979, it was just old equipment - to me it sounded great. I expanded my record collection and used the Fisher and the Thorens turntable daily all through my teenage years.
Finally, when I left to go to college, my uncle had moved closer to home and I made a point to return his system to him - still in perfect shape (except for a couple extra thousand hours of usage on the tubes!) The system sat in his home, used only occasionally (he preferred playing live music himself - trumpet and trombone - he played Jazz with Al Hirt in New Orleans for a time in the 1960's.) So the system sat, in a nice old home in southern Mississippi. Occasionally dusted, maybe occasionally played, but always cared for.
Fast forward again another 15 years, and my uncle's son reached his teenage years. He promptly commandeered the system (as I did 20 years before) and made it his own. Finally, after about 45 years on the original tubes, the Fisher gave up the ghost and refused to play any longer. My cousin left the Fisher, but took the rest of the system to his new apartment in Biloxi, right on the Gulf Coast. It wasn't long after that when Katrina hit and tore through the coast - there was nothing left of my cousin's apartment, not to mention the Thorens table and Warfedale speakers - all ruined by the salty seawater and exposure.

Forward again another six years. My uncle passed away and during a conversation with his family, I mentioned the old Fisher system and reminisced about how much I used to enjoy it. My aunt mentioned that the old Fisher received was still there - it didn't work any more, and I was welcome to have it if I wanted it. Fortunately, the fact that it didn't work any more is what saved it from the same fate as the rest of the system. It sat peacefully in a small cellar while Katrina ravaged the coast and annihilated the rest of the gear.
So I brought it home and here it sits - bringing it back to life with new tubes and a rebuild kit from Jim McShane.
I will be posting photos and descriptions of the process - mostly learned from the great folks on this forum who have already been down this road and gave great advise.

Stay Tuned!!

Fun Read

I like the history- thanks. Look forward to the rebuild.

It was meant to be yours! After all those years, it came back. Makes it that much more valuable to you.

Getting started

Aside from pouring over the AK forums for the treasure trove of information, here are some things I did to prepare:

I read the "How to deep clean a tube amp" sticky by Audiodon (http://www.audiokarma.org/forums/showthread.php?t=406997) and followed his invaluable advice on cleaning fifty years worth of grime from my precious family heirloom. Thanks Audiodon for such a great forum thread!!


Prior to beginning any repair work, I took all the tubes to Austin Stereo and the fellow there tested each one of them for me for a buck a tube. I can't recall his name, but he was very professional and took the time to check each one. Fortunately, most of the 12AX7's were fine. The 7591's and many of the AM/FM tubes were complete worn out.

I contacted Jim McShane regarding a rebuild kit and he worked with me to custom tailor a kit to my needs, including all of the replacement tubes I needed:



I took this picture after having already started on the rebuild, but as you can see, it included all of the power supply caps, important resistors and the coupling, cathode and signal path caps. I also purchased the bias adjustment mod with the single pot and required resistors.

Next up was to take inventory and highlight the parts on the schematic that needed replacement:

Jim was nice enough to send along a PDF of the service manual (also found in the AK database) and I blew up the schematics on 11x17 paper.


I then built a dim bulb tester and purchased a used Variac from Ebay:



It is a 5 amp Variac from General Radio Company, model W5MT3. It was in decent shape when it arrived. Case was a little bent and the strain relief grommet on the power cord was missing. Easy fix.
The dim bulb tester was $6 worth of parts from the local hardware store and a 75 watt and 200 watt bulb.

Here's the 800B on the work bench after slowly and carefully powering up with new tubes:


I had to determine a baseline from which to work. Fortunately, everything worked right off the bat. That made my job much easier!! I did not have to diagnose an existing issue, or worry any more that one of the OPT's were shot, only to insure that I was working correctly as I moved forward by carefully powering up the unit on the Variac as I progressed and checking my work.
Fortunately for me, the Fisher never "broke" as my young cousin thought, just one or more of the tubes had completely worn out.

So here she sits in her current unflattering position - belly up and innards exposed while I ever-so-carefully replace each cap and resistor as included in Jim's kit:

I like these kinds of stories.

Coupling caps, cathode and grid resistors next

With the 800B ready on the bench, I began to work down the list. First up was the cathode resistors:


I carefully snipped the ground lines and replaced them with the 10ohm 1/2 watt resistors.

Next up were the grid resistors and the coupling caps:


I used the Russian paper-in-oil .1uf K40Y's as recommended by Jim. The original 330k grid resistors were replaced with 200k .5 watt film resistors.

After replacing each section, I carefully powered the unit up on the Variac, looking for signs of trouble.

Great story. How about telling us a little bit about what your Uncle did for NASA. Space race program? That sounds interesting too.

Chappy

Hey Chappy,

My uncle worked for NASA right smack in the middle of the space race. He worked on the Ranger and Surveyor missions, the Surveyors being the first American craft to land gracefully on the moon IIRC. The radio telescope location was near Madrid. Most of my recollection of his early days was from the memorabilia he sent back home to my grandmother - there were a bunch of photos taken from the lunar surface (from Surveyor), information on the radio telescope in Spain, and other stuff, including a nice old mono tube amp and preamp along with a huge 5cu ft speaker cabinet with one driver. I was about five or six years old, but I would try to hook the stuff up, but all I got was static. My grandmother would let me play for hours without really looking to see what I was doing - I don't know how I didn't electrocute myself playing with that stuff! :stupid:

That must have been really exciting to have been a part of the space race. Your uncle was part of something really special. The teamwork and collective effort that went into putting a man on the moon is almost beyond comprehension. A bit before my time but still fascinates me nevertheless. I did quite a bit of reading on that subject in my earlier years. I got to meet a few astronauts during my airshow days. Really special for me. I met Buzz Aldrin and then later that day I met Jim Lovell while participating in the Dayton airshow in 2004. I've met others over my career but that day in Dayton really stands out.
Oh yeah, met John Travolta that day too.

Chappy

Wow, that must have been awesome to shake hands with folks like that. Those guys are real legends - on those early lunar landing missions, they didn't know if they would make it home or not. I was just a kid back then, but I stayed glued to the TV to watch every moment of the lunar landings. I can still distinctly remember watching Neil Armstrong climb down that ladder - I was about 5 years old then.
Oh, and I guess meeting John Travolta was cool too. (Just kidding - I understand he is quite the aviation hobbyist as well.)

gguillot said:

Wow, that must have been awesome to shake hands with folks like that. Those guys are real legends - on those early lunar landing missions, they didn't know if they would make it home or not. I was just a kid back then, but I stayed glued to the TV to watch every moment of the lunar landings. I can still distinctly remember watching Neil Armstrong climb down that ladder - I was about 5 years old then.
Oh, and I guess meeting John Travolta was cool too. (Just kidding - I understand he is quite the aviation hobbyist as well.)

Click to expand...

Mr Travolta is a huge aviation buff. That is how we met Buzz Aldrin. I was in error in my previous post, it was actually the show in 2003. We (the demo team I was on) were getting ready to brief our show on the practice day. Mr Travolta heard we were nearby and wanted to meet us. It turns out that he used to own one of our small military training jets. The same jets that our team uses for airshow demonstrations (see my Avatar). He bought the jet after most of them were put up for civilian auction a few years prior. Anyways we went across the airport ramp and met him in front of his own personal 707 which he was qualified to fly. Buzz Aldrin was one of the passengers that he was taking up for a joyride in his "toy".

Those first astronauts certainly had balls. IIRC the initial few batches of astronauts were all military pilots, and most of them were test pilots. They came from an era where death was an all too common occurrence in their line of work. The scenes at Edwards Air Force base in the movie the "Right Stuff" are not too far off from reality. They buried a lot of test pilots back then while testing front line military fighters and X planes such as the X-15.

Chappy

Replaced the first can cap...

Ok, next up was the C102 can cap. It is one of the two cardboard covered caps, meaning the ground is insulated (I think.) I had to work very carefully with this one so as to not accidentally ground it to the chassis.



Also replaced were the diodes at CR3 & CR4 with UF5408 1000PIV 3amp fast diodes, as well as the caps at C103 and C106. They were replaced with .01 1600v caps.


You may have noticed that I replaced the other paper insulated can cap (the bias cap I think), but I did such an embarassing job that I want to redo it before posting a picture. :sigh:

Great Story. I was 6 when Al Shepard, Gus Grissom, and John Glenn went into space. I actually cut school (1st grade) to watch Glenn's mission. It was definately an exciting time to live in. 14 when Apollo 11 set down on the moon. I was glued to a radio for Apollo 13. Even at night. Had an earphone and a supply of 9 volt batteries for my transistor pocket radio. The original 7 were all Military Test pilots at one time or another in their careers. Armstrong was one of if not the 1st civilian Test pilot selected for the Astronaut program.

You're doing great on the 800-B. I'm a little concerned about the K-40Y coupling caps due to their metal can's. Clear heat shrink or something to insulate them would be nice to keep down possible shorts. Are the can caps clamped on the top, I can't tell.

Larry

Really enjoyed the story of your 800B. I used to play my mom's old records too, like Martin Denny's Quiet Village, Billy Vaughn, Al Hirt, Pete Fountain. I wore that Goldfinger album to the bone. Nothing as nice as a Fisher though, we had a cheap tube portable record player. All my rich friends families had the Fishers and Scotts so made me want one when I got older.

Nice work on your rebuild. Smart man to get McShane's kit. I did a 400 with his kit and it was a super learning experience for me.

All the best with the rest of the job :thmbsp:

What size caps does Jim McShane spec on the voltage doubler?

I love the 800B the best. I love the way it sounds, the way it looks, the way it smells, dang it, like old Kennedy era electronics. I have a minty 500B, 500C, 800B and 800C and the 800B wins for that magic tone.

Enjoy your restoration and the end result!

800B also has the eye indicators. Dual indication for signal strength & tune center. Plus, beautiful display color too.

Nice unit! I love the seeing eye tubes!

sony6060 said:

What size caps does Jim McShane spec on the voltage doubler?

Click to expand...

On the 400 kit it's 270 & 560uF

larryderouin said:

You're doing great on the 800-B. I'm a little concerned about the K-40Y coupling caps due to their metal can's. Clear heat shrink or something to insulate them would be nice to keep down possible shorts. Are the can caps clamped on the top, I can't tell.

Larry

Click to expand...

Thanks for the observation Larry. I took special care to make sure there was adequate spacing between the PIO caps and anything else they may make contact with. With the heavy leads on them, I don't think they will move.
And yes, the new can caps came with clamps. Gotta drill holes in the chassis - not too happy about that. :sigh: