• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Fisher 800-c project

apple_scruff

apple_scruff

AK Subscriber
Subscriber
Here is my next project...

Right after I recap my Marantz 18 and replace the 2sc458's in my Marantz 1030. That all should be done by this weekend.

This is a late serial number 49xxx 800-c.

I will keep you posted on the progress.

Does anyone know where to get the plastic clamps used for the AM antenna ferrite rod?

Here is the guts...
 

Attachments

  • image.jpg
    image.jpg
    124.6 KB · Views: 73
Register to hide this ad
The front panel. I have the wood case but it is missing the metal screen.
 

Attachments

  • image.jpg
    image.jpg
    38.2 KB · Views: 40
I made my own from a clear tupperware type container. Cut a 8" strip slightly wider than the mount arm. Instead of 2 clamps you'll have one large one. About 3/4" from the end punch the 1st set of holes. Then screw it on the mount. wrap the strip around the antenna heating the strip with a hair dryer to get it to soften enough to bend, Watch the heat as the antenna is covered with wax and will melt under heat!!!, then approximate where the 90* bend will be for the end stub. Try and get it tight. Make the 90*bend heating it up. Let cool and try to clamp it by hand. It'll be tight. Mark the screw holes and cut off all but 1" from the screw holes. Attach using the screws. If loose use a couple of thin strips of scrap plastic to shim.

attachment.php


It's stronger and more stable than the originals.
 

Attachments

  • 100_4015.jpg
    100_4015.jpg
    84 KB · Views: 228
I am restoring an 800B right now as well. A treasure trove of great information in this forum! It seems every unit I have seen as the AM antenna problem. Must have been a plastic that deteriorates over time.
 
they didn't think that 1/2 a century later that the units would be functioning, and 2 plastics weren't treated with UV blockers and plasticizers that didn't dry up under heat and cool cycles.
 
larryderouin said:
I made my own from a clear tupperware type container. Cut a 8" strip slightly wider than the mount arm. Instead of 2 clamps you'll have one large one. About 3/4" from the end punch the 1st set of holes. Then screw it on the mount. wrap the strip around the antenna heating the strip with a hair dryer to get it to soften enough to bend, Watch the heat as the antenna is covered with wax and will melt under heat!!!, then approximate where the 90* bend will be for the end stub. Try and get it tight. Make the 90*bend heating it up. Let cool and try to clamp it by hand. It'll be tight. Mark the screw holes and cut off all but 1" from the screw holes. Attach using the screws. If loose use a couple of thin strips of scrap plastic to shim.

It's stronger and more stable than the originals.
Click to expand...

Very clever, Larry. I like it. :thmbsp:
 
Thanks for the tip from mouser. I will take a look at what they have. In the mean time made a bracket out of pvc sheet stock that I heated and formed based on the tupperware idea. Thanks!!!

I recapped the 18 and got the 1030 transistors in so onward to the 800-C!!!

I have been reading on the IBAM and will install that.

The AM loop antenna has the ground wire off of it. Normally you can see where the wire goes as you usually see evidence of its former location. In this case I cannot tell. Can someone please let me know if it goes to the ground lug or the tap? Or can some one take a picture where the green wire goes and post it?

On the Heyseed Hamfest capacitors... Does anyone know the part numbers or do I just ask for them by the value or model number?

Thanks!
 
On the hayseed can's Tom has the set numbers. Just tell him you want the full set of 800-C can's. he's backed up right now (I've got a set building again for another one). Be about 3 weeks for them to get built.

One more thing you guys doing the 800'c can do is the screen grid mod. Our own Dave Gillespie wrote an article about increasing tube life and one of the items was ARCING of the screens. www.tronola.com and click on Dave's lb, then click on Increasing tube life or words to that effect. A 100oHm resistor on the screens for each tube is all thats required. The mod is drawn up in the COMMON ITEMS FOR FISHER's needed STICKY at the top of the Forum page. Just follow the directions. Great mod and cheap too.

Here's what it looks like. Note the piece of Romex 12ga running across the outputs. That is the new buss wire. The resistors drop off it to the tube jumpers that has been cut between the tubes to isolate each.

attachment.php


attachment.php



Larry
 

Attachments

  • 100_3940.jpg
    100_3940.jpg
    151.9 KB · Views: 200
  • 100_3943.jpg
    100_3943.jpg
    151 KB · Views: 200
That looks like a sensible mod to do as well. Thanks!

So far I plan on doing the following to the 800-C:

Rebuild kit from metalbone or others (still researching)
Power Supply caps from Hayseed
Remaining electrolytics.
IBAM
Inrush limiter
Screen Grid mod

Assuming all the tubes are good am I missing anything?
 
10 oHm cathode resistors (pin 5 to chassis ground) (*)

Change Grid resistors to 200K or 220K in conjunction with .1uf coupling cap increase (*)

Individual pin jacks for output draw (**) (Connect to pin 5)

Eventual installation of EFBII when available.

Replacement knob brights (if needed).

Doon't forget on the dial glass, clean only with a qtip around the lettering. Don't touch the lettering. Or you'll end up with a dial that looks like it was written by a kindergartener!

Apple scruff. Just noticed you have a 500-TX. Running? How do you like it? Mine is 100% and I have the RK-30 wired remote for the Autoscan. IMO between it and the 800T the best S.S. receivers FISHER ever made. Wish I could get some lettring for my front panel. Pretty much wasted away.

(*) Should be part of McShane Kit.

(**) Part of IBAM
 
Last edited:
The 500TX was running last year when I took it offline. I used it in my office for years. It is setting in a cabinet now. I really liked it. I even have the wired remote for it as well. It is in absolute great condition 9/10 other than the wear around the volume control.

The ReVox A78 took its place as it seems to have lower noise floor. I rarely listen to the radio. I usually listen to CD's or Albums. The Marantz 18 I just rebuilt is in my office now so I can give it a work out to be sure it is stable.

I just pulled it out of the cabinet and stacked them for a photo...
 

Attachments

  • a78-500tx-18.jpg
    a78-500tx-18.jpg
    80.5 KB · Views: 35
Real cheap insurance against getting frizzy hair: X1Y2 cap (aka) Death Cap. Can't tell you exactly which cap cuz I'm not home but I'm sure someone here could.
 
Well I ordered the Hayseed Hamfest capacitors, I am in the queue! What a very responsive and pleasant company! They are four weeks out on production. That will give me some time to gather the rest of the parts and clean the chassis!

I also just ordered the metalbone kit.

notdigital,
If you can give me the reference designator for the cap I would appriciate it.

Thanks All!
 
Last edited:
That's it. There are 2 either .1 or .01 caps right next to the diodes. Replace the one off the AC line with the X-Y and the other with a regular film cap.

Larry
 
You must log in or register to reply here.
Back
Top Bottom