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New to Tubes...800c score...help restore.

marloubow

marloubow

Best Day Ever
I'm so jazzed, :banana: I don't know where to begin.
This is my first real venture into tubes, so please be patient.
I have been reading a bit about tube amps and looking at some different kits or hoping maybe to find some old console.
After a fairly weird morning at work I ventured over to one of the local thrift stores at lunch. Upon driving past the alley where the drop offs are I saw in the thrift store's discard pile what looked to be a speaker cab sticking out.
On closer inspection I didn't find a speaker but did find a Fisher 800c...my heart was racing. I remember thinking "should I just take it, or ask if I can just have it". About that time an employee came out and asked the manager/owner and she said I could have it.
Turned my whole day around to say the least. Also in the pile was documentation, a Garrard Lab Series Type A MarKII TT, plus a Blonder Tongue tube FM stereo booster. Makes me wonder what else doesn't make it to the floor...(sigh).
Got it back to the house and inspected it and decided to go ahead a plug it in just to see if it would light up. I don't have a variac, but figured the thrift store had already tried and hence the junk pile. But light up it did.
But I think it has issues. Before I actually hook it to a pair of speakers I need to ask about a couple of things.
1) I did notice a light electrical current running through the chassis, faceplate and speaker terminals. Bad cap tied to ground?
2) At power up one of the 2 display bulbs goes out after 10 seconds. I verified this 3 times.
This is as far as I got and shut her down.
Do you guys think I'm okay to go ahead and hook a pair of speakers (cheap) and a source and do some more checking?
My electrical knowledge is limited. I'm pretty comfortable with a soldering iron and almost "get" multi meters. Most of my experience has been mostly recapping vintage speakers. I have built an Aksa Amp and an Aksa TLP (both kits) with much email help from Hugh Dean (thanks again Hugh).

I was up to about 2:30 last night reading about the 800c here and I am truly excited! Alot of great guys here sharing experiences.
Went back today to see if they had the case...no.
I hear the glow of tubes is quite mezmerizing, so maybe no loss.
This 800c is in great shape cosmetically...zero rust or scratches.
Really looking forward to the journey.
Thanks for the help in advance.
Martin
P.s. I promise to be less wordy in the future.


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Jaw dropping. Awesome. I don't know where to start except to say congratulations. Many will chime in with good advice. Enjoy!
 
Since this is specific to a piece of Fisher gear, moved to the Fisher Forum.

Oh, and congrats on a spectacular find!! That thing is a BEAUTY! :yes:
 
No problem!

Btw, the light going on and then off is probably an indication that you are not locking onto an FM stereo station, due to the fact that you don't have an antenna connected. Based on what you've said, I would be willing to connect a pair of speakers and a CD player for a test.

Then, you need to do the usual cleaning of all contacts, switches, and tube sockets.

Your 800C is completely original, and hasn't been touched. Do some searches here on AK and you'll find excellent information on what basic restoration work you should do before any extended listening sessions.
 
First off great find and you must be living right. Don't play it without hooking up speakers. tube amps don't like it. I know your stoked right now but take a step back and say to your self. Do I really want to to take the chance of doing real harm to this great vintage receiver or would it be better to find someone knowledgeable to help me out. Reading everything you can is an excellent thing to do. Study the chassis and objectively evaluate your skills and decide if it's within your skill set. Good Luck. I'm sure you'll love it when it's right.
 
Yes fisherdude...i will probably do a metalbones restore kit.
Most of my reading was in the tube forum with an 800c search...will do more in the fisher forum. FM Stereo beacon light it is...doh!

Sanford12
I do have a repair guy who has done right by me so far. I talked to him today and is willing to have a look at it...although I think he is a bit backed up
 
Actually he can run it without speakers as long as he's using headphones. Turn the speaker switch to OFF. Plug in headphones, and turn it on.

Couple of things to do right of the bat.

READ READ READ the Service Manual, and LEARN to Use the VOM. Those two items will be your RIGHT AND LEFT Arms while working on the 800C.

Get the tubes tested, and replace any weak or non functioning tubes. Don't worry about "boutique" tubes right now. You want a baseline sound to compare any improvements made.

First items to replace.

BIAS SUPPLY components. Selenium Rectifier, Bias caps and resistors to adjust voltage to -19V, -20V. Yes NEGATIVE VOLTS. The manual will say -17V or so, but that is running the tubes harder than spec. Get the bias voltage up and they will run smoother and cooler, and last longer.

Test Unit.

Coupling caps to the 7591's. Change to .1uf 600V and the resistor from 330K to 200K to 220K oHms.

Test Unit.

Power supply caps.

There are some cap kits, namely metalbone, SDS(Board kit for power supply/bias). Jim McShane also makes up kits for these. Jim's kits are more for the intermediate kit builder / someone who's familiar with Tube circuits. Metal bone kits are fine for beginners.

Or you can browse the Mouser catalog and pick your own caps, resistors.

The CAN CAPS can be disconnected and the individual sections replaced by individual caps. This should be done after everything else as the caps get in the way of everything else. Or they can be replaced with custom built Can caps from Hayseed Hamfest. His caps are built to your custom spec, and fit in with no problem. The cost of his caps are slightly less than generic multi caps from various vendors. And no modification needed.


I couldn't PAY to fall into a deal you got today. Wanna trade a recapped 400??? :D

Larry
 
WOW!!!
Why this 800c was in the discards I'll never know. :scratch2:
It's playing wonderfully as we speak. Will work on cleaning chassis, pots and switches. Ballance seems to be a'okay.
Wow this is awsome...and thru mediocre speakers! :thmbsp:
The slight current I was feeling in the chassis is gone as well...swallowed up by the speakers I presume. :thmbsp:
Not even a wisper of hum on either channel...excuse me while I change my shorts. :D
Martin
 
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Holy cow!!! :jawdrop:



The tuner section is awsome. I'm in my basement with 12" of baling wire for an antenna...4 on the signal meter...beacon light is on.
Very clear! :thmbsp:
Guys I'm sorry...I'm don't mean to gush...but, WOW!!!:banana:
Feel like I won the lottery.
martin
 
Holy crap. Not only a free 800C, but a beautiful example with all documentation and the original Fisher-logo 7591s! BTW, you might want to get some more generic and used output tubes to use until it's had a full restoration, you'd hate to damage one of those rare outputs. I assume the rest of the tubes are the original Fisher-branded parts, too? The 12AX7s and 12AU7s are most likely Telefunken or Mullard, and quite a score on their own.

Knob brights are available from several eBay sellers.

I'm jealous of those output tubes - the only non-Fisher tubes in my 800B are the outputs.

The Garrard A is a pretty darned nice TT, too - it was about as high-end as you could get in a changer for the era. The Thorens TD-224 was probably the only thing above it.
 
Sam
All the tubes are all original "The Fisher" except for one.
One of the 12AX7 (V17) is a GE. When I removed the bottom cover there was a small amount of glass shards. Remnants of the missing 12AX7 tube I would venture to guess.
Most of the tubes (inc.12AX7's) are "made in west germany". :thmbsp:
6AU6 - Gt. Britain
7591A - USA
others I can't read the location of origin.
My 800c has no 12AU7's
martin
 
marloubow said:
Sam
All the tubes are all original "The Fisher" except for one.
One of the 12AX7 (V17) is a GE. When I removed the bottom cover there was a small amount of glass shards. Remnants of the missing 12AX7 tube I would venture to guess.
Most of the tubes (inc.12AX7's) are "made in west germany". :thmbsp:
6AU6 - Gt. Britain
7591A - USA
others I can't read the location of origin.
My 800c has no 12AU7's
martin
Click to expand...

West Germany = Telefunken (most likely, I've never heard of Fisher buying from the other German manufacturers like Valvo). They'll have a diamond stamped into the bottom if they're Teles. Be extremely careful with the painted markings, they're basically made of dust.

Gt. Britain = Mullard. Should have seams on the top.

I think those 7591As will be Sylvanias, but I'm not sure. Possibly Westinghouse. Sylvanias will have the "312" EIA code somewhat prominently displayed on the tube.

Get that GE 12AX7 out of there. They made great output tubes, and their 5751s are reputed to be excellent, but I can't stand their 12AX7s. Keep an eye on eBay, you should be able to find another Fisher-logo Tele or Mullard 12AX7 for a reasonable price.
 
There are several listed for $15+$15 shipping. Not sure why the shipping is so high, eBay redid their fee structure to get rid of people scamming them with low prices and ridiculous shipping.

I'm not a fan of GE's small-signal tubes, and it seems like it would be cool to have all Fisher tubes as original as your unit appears to be. It's not going to hurt anything, other than possibly somewhat degrading sound quality in that circuit. For US made tubes, I've found that Sylvanias sound very, very good in Fisher gear.
 
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