Really clueless need help on Fisher 500B

[doom]

Hello,

I have a fisher 500b and really need help on this, as the fisher doctor is probably not responding and I dont want he to hold my receiver endlessly...

The Fisher 500b and it is excellent. When I used Aux and FM it produce some of the most wonderful sound and both channel goes strong. However, we I put a phono input in, I notice that the right channel is a little fainter than the left channel ( about half), and also it has some more noise, this is very noticeable when I use the balance to switch between left and right. and only in phono input. This happens to 2 of my turntables so it should not be a turntable problem.

I am not really able to fix anything electronically so just wondering should I try to replace the two 12ax7/ecc83 tube in the phono section to give it a try? If professional restoration is needed, anyone can suggest a good one in NJ? I dont really want to ship vintage electronics...

Many thanks

 

[Saint Johnny]

Hello,

I have a fisher 500b and really need help on this, as the fisher doctor is probably not responding and I dont want he to hold my receiver endlessly...

The Fisher 500b and it is excellent. When I used Aux and FM it produce some of the most wonderful sound and both channel goes strong. However, we I put a phono input in, I notice that the right channel is a little fainter than the left channel ( about half), and also it has some more noise, this is very noticeable when I use the balance to switch between left and right. and only in phono input. This happens to 2 of my turntables so it should not be a turntable problem.

I am not really able to fix anything electronically so just wondering should I try to replace the two 12ax7/ecc83 tube in the phono section to give it a try? If professional restoration is needed, anyone can suggest a good one in NJ? I dont really want to ship vintage electronics...

Many thanks

Have you tried Tim Schwartz at Bristol Electronics, in Ho Ho Kus? He's in Bergen Co., a few miles up Rt. 17 off the GSP.
Tim has one of my 500B's as I type this.

 

[drknstrmyknight]

Easy enough to swap the tubes in the phono section to see if they are weak, noisy, microphonic, etc. Should be the 12AX7's right behind the tuning eye.

 

[sgmlaw]

Every 500B should be recapped at this point. If this hasn't already been done, you are only inviting continuing issues.

Otherwise, swapping the tubes across channels is always a good first diagnostic step. If the trouble swaps channels, you've found the problem.

 

[Ciscokid]

Hi,
I have a 500B and I agree that this unit sounds wonderful. My 500B has a pair of phono level pots on the back of the unit. Check these pots and adjust as necessary.
Hope this helps,

Danny

 

[Fisherdude]

Hi,
I have a 500B and I agree that this unit sounds wonderful. My 500B has a pair of phono level pots on the back of the unit. Check these pots and adjust as necessary.
Hope this helps,

Danny

With all due respect, adjusting those when you have not yet done the necessary troubleshooting and restoration work will only hide the problem. That adjustment, if necessary, is done after the required work is complete. I would suggest that unless doom has the expertise, he shouldn't make this adjustment.

 

[derekva]

One more suggestion - check your solder joints for the phono internal wiring - you may have a cold joint at either end (RCA end or rotary switch end). I had a similar problem on my 800c and reflowing the RCA connection fixed it.

However, I agree 100% with performing a recap (as well as all the other work you should do to preserve your investment). Do a search for 500b or 500c or800c in the Tube forum and you'll find a goldmine.

-Derek

 

[visman]

Another simple step to help identify the problem is to reverse the left and right inputs on the Phono (if problem stays on same channel you know for sure it's the receiver and not the turntable - or record).

 

[Ciscokid]

With all due respect, adjusting those when you have not yet done the necessary troubleshooting and restoration work will only hide the problem. That adjustment, if necessary, is done after the required work is complete. I would suggest that unless doom has the expertise, he shouldn't make this adjustment.

I agree to a certain extent, however, what I should have made clear is to check to see if these pots are properly adjusted in the first place. If one is turned way down with respect to the other, then you may well be trouble shooting a non existent problem. One never knows, but these pots are easily accessed and very well could have been twisted and turned over the years. And yes, this unit should be properly restored and adjusted before using as should be done on all vintage gear.

Kind Regards,
Danny

 

[doom]

Thanks all, guys, lots of valuable information for me to try... I agree a restoration is needed, only thing is when I purchased this unit 3 years ago I was told a complete restoration is done on it but who knows....

I will definitely try Tim in Hohokus... so many gears I have may need that services....

 

[Fisherdude]

I agree to a certain extent, however, what I should have made clear is to check to see if these pots are properly adjusted in the first place. If one is turned way down with respect to the other, then you may well be trouble shooting a non existent problem. One never knows...
Kind Regards,
Danny

Oh, very true. You never know what the previous idio..I mean owner, did to a unit.

Thanks all, guys, lots of valuable information for me to try... I agree a restoration is needed, only thing is when I purchased this unit 3 years ago I was told a complete restoration is done on it but who knows...

Post a few pics of the underside. We'll be able to at least give you an idea what, if anything, was done in the past.:yes: