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Fisher Four-hundred Fotos?

Congratulations -- don't it feel good? :-)

As far as the FM, I am leery of futzing with any FM section that is working reasonably, because one (I!) can do more harm than good. "if it ain't broke, don't fix it" would be my advice.
 
There are some people who feel that removing the two 19KC filters in the MPX stage is a "bad idea".

In theory the filters are "only" supposed to filter out frequency above 19K...but in practice they do cut into the audio band which on FM is limited to 15K.

You can view this on a scope.

If you have doubts...you can always put the filters back in...although I have no idea why you would want to.

Changing the de-emphasis is also a major upgrade that some people feel is a bad idea. The stock de-emphasis is to extreme...and the sound is a little to lush. Again this is something you can change back to stock if you do not like it...none of the tuner mods are permanent.

The best thing you can do...is have the tuner aligned. It makes a tremendous difference. I am still amazed everytime I do an aligment on a Fisher unit how much of a change there is!!!

A professional alignment, fresh tubes, and the mods...will make you wonder why you ever need anything other than a Fisher receiver!!!

Glad I could help on your bias problem.
 
The filters are actually 38k. I believe the now "nowhere to be found" FisherDoc started the 19k misnomer. I have not observed them cutting into the audio band at all. I use FFT spectrograph, a good fm generator and a good sine wave generator.

I had one go bad and saw the hash it creates on a scope. It was audible on my Khorns, that is why I started troubleshooting.

Terry and I have found a workable comprimise for the de-emphasis problem that does not require removing the coils. If you are interested I will post the how to.
 
Audioreality said:
Count me in, Mark....

I have a stock, near mint 400 that would be nice to compare with a re-done unit.
I wouldn't mind seeing some nudes to get an idea of what i'm in for.

Whattayasay?

Regards,
Crazy John.
Click to expand...


John,

Heck I'm still waiting for you to come get this ST-70 with all the parts to rebuild it ;) Heck what has it been 3 years?? Heck I tell you what I have one with the rebuild already done that I took in on trade for VRD amps if you carry yourself to Southfield for the AKfest this year (March 24th/25th) I'll give you this one with the work already done in place of the other one!! We need to drink a few beers together! Bring a sleeping bag and you can crash on my hotel room floor!

Craig
 
Hey brother....
It's been a while, hasn't it?
Time flies when you're havin' fun. :)

ST70????
What's that?

Oh yeah......
I remember now.
Lol. :)


I would like to make it this year.
Still have to figure out the transportation thing.
(as usual)
My old daily drivers just aren't trustworthy enough to make the journey.

I'll let you know, soon, if I can make it out.
....and yeah......crashing on the floor sounds like a plan.
Party time!


Regards,
John
 
Hope you guys still check out this thread. I purchased a Fisher 400 about two months ago and could not be happier with it. Although it works great I would like to do some of the "upgrades" for lack of a better term to ensure the component continues to function for many happy years to come. It seems to me the most important changes to make soon would be the selenium rectifier, coupling caps, and the electrolytic caps. I would have no problem changing them even though I am a beginner at restoring vintage gear; my only problem is where is the best place and best brand to buy the replacement parts? Does anyone have sort of a "shopping list" of what to buy and brands to do a good overhaul? I hope this is not too much of a newbie question for you guys.

Thanks,
mike
 
i replaced the old coupling caps with orange drops in my 400, sounds really nice
the rectifier and the two 1000 uf caps i got them from the shack
it's working great and fits perfectly where the old one was
i like to buy my all my parts locally if i can
 
All good advice above. Orange drops sound quite nice IMO. The even-cheaper Illinois caps aren't bad, either. Radio Daze and Antique Electronics Supply each carry both, as I recall.
R/S parts are fine for the bias supply, IMNSHO.
 
Fisher 400 - different Voltages V9 - Pins 1/6

Do somebody know how diffent Voltages are comming from ?

My Left Channel is stronger, then the other.
Measurements shows different Voltages.

On the left Channel, I have a higher Value.

So, i bought a Shematic.

Tube V9: Pin 1 and 6 should have same Voltages. Right?
Tube V10: Pin 1 and Pin 6 should have also the same Voltages. Right?

All Pin 1 and 6 are at the same Point at the Shematic.
Its a Symbol, a Triangle with the Big "B" Letter.

They should have 160V+

The other Side of the Triangle"B" have in the Shematic, 286V+ ( or 266V+ ).

There is a Connector Bar with 8 Points: 1-2-3-B4-C5-D6-E7-F8.
( described as "MPX 65 CONNECTIONS" )

Are the Triangle "B"s mean, "connected" or not?
I cant find any Connector with 8 Lugs.

The Shematic is for Fisher 400. My Receiver is a Fisher 400.
What is here wrong ?

Please help me, before I jump trough the closed Window ;-)

Darko
 
Thanks!!!!

I am a Professional Photographer and I think these are great photos. They provide a wealth of information.
I have a newer Fisher 400 (serial # 780xx). But I got worried about the selenium rectifier after reading a few posts. I see the selenium rectifier in your original and that mine bears a resemblance to your "black thingy" silicon rectifier - but mine has several heat sink type fins, so you've set my mind at ease.

Thanks.
Dennis
 
My Fisher model 400 (serial number 80733) also had a silicon rectifier with the fins attached. Worked fine...but I wound up replacing it anyway.....
 

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Dadbar... just whereabouts, roughly, in the Boston area are you? :-)
There are more than a few of us nuts in the vicinity, y'know?
 
Bump.....

I know this thread is at least 3 years old, but it's worth the bump for all us who have recently gotten or are getting 400's. Making up a parts list tomorrow.

Larry
 
Hi Larry,
Me again. I have a 400 as well. Maybe we have a group project here. Some of the 1000a stuff I've collected will work here too. Let's talk.
John
 
A few Christmas's ago I found a 400 on the curb - I had it rebuilt by Craig Ostby and use it regularly (multiple times a week) with my 650 headphones. I can post a parts list from his "rebuild" which was more of a tune up then a rebuild it that would help.
 
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