It's a great feeling to know you did the work yourself, it was something you've never done before, and it came out working perfectly!
Congrats and enjoy!
Dave
Congrats and enjoy!
Dave
The "new to me" 500B
- Thread starter Rockyhill
- Start date
The receiver is now on top of a cabinet where I can look at it more closely. I noticed V2, 1st IF amp, was not lit (the other 6AU6 were dimly glowing). I tapped it and it came to life. I swapped the three 6AU6 tubes around and they all lit up. I connected an antenna and voi la, local FM reception!
vsat88
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Thats awesome, sometimes...its the simple stuff !
Rocky; If you have to tap a tube to get it to light up or work, it indicates one of two things which is causing an intermitent. The tube will eventually lose it's grip on the socket and die off again until you re-tap it.
1.) DIRTY Tube socket contacts or tube pins.
2.) Loosened tube sockets.
Solution: Clean and Readjust/tighten all the socket pins, and the tube pins themselves.
Larry
1.) DIRTY Tube socket contacts or tube pins.
2.) Loosened tube sockets.
Solution: Clean and Readjust/tighten all the socket pins, and the tube pins themselves.
Larry
The sockets had several blasts of D5 a while back but the pins hadn't. Will clean henceforth. Need to research retensioning the sockets.
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Get a jewelers or Dental Pick. Insert the end of the pick into the gap between the metal socket leaf and the socket wall. Twist to tension the leaf toward the center. Do this for each leaf.
If you have a Welding supply house nearby, get a set of gas torch tip brass brushes (mig or tig tip brass brushes will work also if small enough). Insert brush into the socket and spin the brush a few times.
If you have a Welding supply house nearby, get a set of gas torch tip brass brushes (mig or tig tip brass brushes will work also if small enough). Insert brush into the socket and spin the brush a few times.
Rocky -- THAT is a gorgeous B that I'm sure you're rightly proud of (you should be)! Congrats on a job well done!!
Dave
Dave
Thanks Dave. I'm very pleased with how this turned out. It sounds better than I expected. This is my second project you have mentored - previously it was the EFB mod to my ST-35. After following the Fisher forum and learning from many contributors- with special props to you, Larry and Don - I decided to embark on this project. I also have to thank my wife for understanding why I wanted to spend money on a 54 year old electronic item. She loves the way it looks and sounds. WAF is critical to this obsession!
There are still some things to complete, such as the phono section grommets and painting the xformers. Tube rolling too.
Next project will probably be a recap of my Marantz 2235B. A classic from the decade that followed this Fisher.
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Go for it. Use the same procedure for the tungsols.
Dial Lamp Repair
Thought I’d share this repair anecdote. I don’t have pictures so my words will have to suffice.
One of the dial lamps wasn’t working. Upon removal discovered one of the metal end caps was disconnected from the lamp. The wire from the filament was still intact. I measured continuity between ends and determined the filament wasn’t burned out. Assumed there was still a vacuum so I decided to repair. I sucked the solder off the tip of the end cap, exposing the hole at the end. Placing the cap back on the glass the wire didn't come through the hole so it would need to be lengthened in order to solder to the cap. Took a few strands of wire about ½ inch long and soldered them to the lamp wire. Pushed the cap tight against the glass and soldered the wire. Cut the wire flush at the solder, popped it in the lamp socket and powered it up. Voila! Two working dial lamps.
Thought I’d share this repair anecdote. I don’t have pictures so my words will have to suffice.
One of the dial lamps wasn’t working. Upon removal discovered one of the metal end caps was disconnected from the lamp. The wire from the filament was still intact. I measured continuity between ends and determined the filament wasn’t burned out. Assumed there was still a vacuum so I decided to repair. I sucked the solder off the tip of the end cap, exposing the hole at the end. Placing the cap back on the glass the wire didn't come through the hole so it would need to be lengthened in order to solder to the cap. Took a few strands of wire about ½ inch long and soldered them to the lamp wire. Pushed the cap tight against the glass and soldered the wire. Cut the wire flush at the solder, popped it in the lamp socket and powered it up. Voila! Two working dial lamps.
vsat88
Like my Bluetooth ?
I will keep that one in mind. Awesome you were able to fix it. Did nearly the same job on the OT on my 500C. The tiny repairs are often what make me the happiest, especially being I do not see nearly as well as I used to.
Last night I placed my fingers on an OPT to see how warm it was. FM suddenly went nearly silent. Jiggled the 6AU6s and sound returned. (Recently I've also noticed the FM will just stop playing unless I turn the tuning knob, then it returns. )
This morning I pulled the original Fisher/Mullard tubes, cleaned the sockets and pins of NOS Sylvanias I recently received. Put them in - seems like these fit more tightly - and powered it up. So far no drop off of signal. A favorite, more distant channel comes in more strongly as well.
Here's another odd symptom. If I sit near the receiver and plug in the power cord of my laptop I get some noise/hiss with FM. It goes away if unplugged.
The AC filter caps are new and I rotated the power cord in the outlet but no change. With the new 6AU6s this symptom stopped. Would this have been due to the out of spec tubes and RF coming from the laptop charger being picked up by the rabbit ear antenna?
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Possibly out of spec tubes that wouldn't let the final IF stage limit like it's supposed to -- but more likely just junk from the switching power supply in the AC adapter for the laptop. Those adapters clearly have their advantages when it comes to flexibility, but when it comes to noise, I hate the darn things.......
Dave
Dave
Channel Imbalance in upper mid to high frequencies
The past few days I've noticed a slight L vs. R volume imbalance. Initially I thought it was FM only but after swapping all tuner tubes it remained. Played a few CD's and it's present there as well.
Further analysis showed it's in the upper mid to high frequencies in the L channel - they are diminished with respect to the R. Speakers are Infinity RSb's which tend to be bright so it's quite noticeable to me. If I use the Channel Reverse switch it moves accordingly so it's not the speakers.
In the diminished channel I hear a bit of soft rumbling. Would this be from the tone control amp 12AX7? I'll swap the tubes once cooled and if I can reach them with the case on.
The past few days I've noticed a slight L vs. R volume imbalance. Initially I thought it was FM only but after swapping all tuner tubes it remained. Played a few CD's and it's present there as well.
Further analysis showed it's in the upper mid to high frequencies in the L channel - they are diminished with respect to the R. Speakers are Infinity RSb's which tend to be bright so it's quite noticeable to me. If I use the Channel Reverse switch it moves accordingly so it's not the speakers.
In the diminished channel I hear a bit of soft rumbling. Would this be from the tone control amp 12AX7? I'll swap the tubes once cooled and if I can reach them with the case on.
Ongoing constant maintenance is almost mandatory 
with these older sets. It seems I end up pulling the 800C from the Executive about every 12 weeks for cleaning tube sockets, or pots/switches. Eventually they'll wear out, but that'll be my grand-daughter's problem. LOL! Maintenance to operation hours ratio is beginning to look like an F-14A. 1 hour operation to 50+ hours of maintenance.
with these older sets. It seems I end up pulling the 800C from the Executive about every 12 weeks for cleaning tube sockets, or pots/switches. Eventually they'll wear out, but that'll be my grand-daughter's problem. LOL! Maintenance to operation hours ratio is beginning to look like an F-14A. 1 hour operation to 50+ hours of maintenance.
Ongoing constant maintenance is almost mandatory
I'm glad I'm not alone with this maintenance! However the 500B sounds amazing once tuned up so it's worth it.
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For a speaker rated at 6 ohms which connection should I use? These are just some small el cheapo brand that were my dads and will only be used when on the work bench. Will also use them on my ST-35 when checking bias on each amp. Assume the answer will apply to both.
Thanks
Thanks
