Fisher 800C question

Hello to all, I just unhooked my FM200B and amp and hooked up my 800C after a 6 month break, sonically I have to say I prefer the 800C although the X202B and FM200B were great. Have learned to rotate equipment from you kind folks in here. My question is that the balance on my 800C isnt balanced so to speak, have to adjust the balance switch to the left to get a even sound, its always been this way and I aquired this as restored.. Wondering is this is simple fix? I ahve owned this for about 3 years. Any help would be appreciated..thanks

Could be the volume control itself. Is it the same imbalance in all functions--phono, radio? Does it change if you slightly wiggle the knob?

Agree it's most probably the volume control. FISHER's Volume controls are fairly known to have this problem. The Carbon tracks on the pad's inside wear at different rates and you then get a volume inbalance. You can check it with an oHm meter across one of the outer and the center leads on both channels. The readings should match up within 1-2%.

How far over on the balance do you have to move it. TRY IT In MONO. BALANCE IT OUT IN MONO so the sound seems to come from the middle. Look at the balance pot position. Either live with it (if it's minor) or pull the knob off at that point and re-position it to center. You can also send the volume pot to Mark OPPAT @ http://www.oldradioparts.net/index.html and he'll rebuild it so it's right.

Larry

My first guess would simply be asymmetrical wear and/or dirt inside the balance pot or volume control, or else normal aging/drifting of component values and tube parameters in related circuits. Since you mentioned that it's always been this way, I would suggest cleaning the controls, and you could certainly check the tubes as a simple experiment.

Keep in mind, the purpose of the Balance control is to set the l/r volume level so it's pleasing and centered to the listener. Whether you move it because you've got big glass doors on one side of your room and floor to ceiling draperies on the other side, or if you adjust it to accommodate internal variances in the circuits, it's all good. That doesn't necessarily mean you need to repair something.

Mark is THE volume pot go-to guy. I can't recommend him highly enough.

If the balance misbalance is the same at all volumes, I typically remove the balance control knob, put a screwdriver in from the back of the knob and pop off the balance knob bright.
Then I put the knob back on, verify that things are balanced at all volumes and glue the knob bright with the indicator line pointed to the centered position with rubber cement.

Is it cheating? That's up to you to decide. My take is that if it's a tracking issue in the volume pot, the balance will change depending on how loud you're listening. If that's the case, I dig deeper.

Hello and thanks for all your replys on this guys, really appreciate it. Tonight I played it mono and balance was even, then switched back to Stereo auto and thats when the imbalance seems to ocurr, same thing when playing a CD, tryed them both. That being said to me it seems the on/off volumne switch is ok? I do have a new switch I bought from Metalbone a year or so ago, if you guys think I need to try that after this then let me know. I have followed a ton of posts in here and have learned to collect parts...even have 6 original feeston lamps for this 800C..anyway, your suggestions appreciated, may god bless!

The switch from metalbone is only the actual switch part that goes on the back of the volume control. You reuse your existing volume control, so, if it's the volume control that has the imbalance, changing the switch won't help.

Have you tried some contact cleaner in the volume control and balance control?

Oh, and it's "festoon". :stupid:

Thanks Fisherdude, no I havent but dont know how to do that, novice here..still learning. Perhaps I need to find a tech but would rather do it myself. I'm 61 yrs young and grew up with Fisher gear,thats why the love of this stuff, used to listen to my dads FM1000 back in the 60's.. and yes your right, it is Festoons,lol, thanks!

AlTinkster92 said:

Thanks Fisherdude, no I havent but dont know how to do that, novice here..still learning...

Click to expand...

Here you go: http://www.audiokarma.org/forums/showthread.php?t=207005

Sorry for the length; it's the Encyclopedia Britannica when you only needed a paragraph, but it's everything you ever wanted to know about using De-Oxit or any other contact cleaner.

Basically, with the power off, spray contact cleaner inside the pots through any opening you can find, and then work it gently back and forth through the full range of motion, at least 20 times or so. Let it sit for a few hours before powering back up. If it doesn't completely fix the problem try it again in a week. If that doesn't fix it, it's not from dirty controls. Generally, after cleaning potentiometers with any contact cleaner, the use of FaderLube is recommended to lubricate the internal resistive elements.