Starting my Fisher 400 restore

[ncwalz]

Decided to begin my Fisher 400 restore. I knew some work had been performed at some point in the future as the previous owner told me that the on/off switch was defective and an inline switch had been installed on the power cord. I do have a replacement Fisher switch I bought from Metalbone a couple of years ago and a spare Fisher power cord in good condition. I also bought a Jim McShane upgrade kit and then decided to get the electrolytic can replacements from Hayseed Hamfest.

I can see where the switch was bypassed (black wire from accessory outlet shorts both terminals on terminal strip) which should be easily corrected once I install the new switch (second photo).

It also appears that someone replaced the rectifier bridge with 4 individual diodes (first photo). Have I got that right?

 

[larryderouin]

You got it right. Although you'll end up replacing those hi-hat diodes with a bridge rectifier with Jim's kit.

Would you go to the FISHER 400 OWNERS....READ THIS thread and provide me some info on your's. Namely Serial #, the number of RF/IF tubes, and the info off the side of the output transformers, please.

If you run into any problems, stop, and post a couple of pics of the offending area, along with a description of the problem and we'll help you out.

Larry

 

[ncwalz]

Thanks Larry!

I added my Fisher 400 info to your thread a few days ago.

 

[bhamham]

I used Jim's kit on my first Fisher 400 restoration. Quality parts. Good luck with yours!

 

[ncwalz]

I used Jim's kit on my first Fisher 400 restoration. Quality parts. Good luck with yours!

Thanks bhamham. I used Jim McShane's upgrade for my 500c with excellent results.

 

[ncwalz]

Just a question for the experts:

I’m planning on restoring this 400 using Jim McShane’s kit as well as some of the other upgrades (removing tape to aux bleed, removing the garrotte from the phase inverter tubes, and installing IBAM). I’m still thinking about whether or not I’m up to installing EFB.

The 400 will be gifted to my youngest son who has taken an interest in the tube sound. As such he would be likely using the auxiliary input only via a DAC. He won’t be using the phono input or listening to FM. He might use the tape input.

I have obtained a new set of output tubes from McShane, but I know most of the other tubes are pretty weak based on my Hickok 600A tube tester. Other than the output tubes, phase inverter tubes, tone control and voltage control tubes, do I need to worry about the quality of the other tubes?

Thanks

 

[audmod01]

ncwalz;

Yes, those top-hat rectifiers really date the repair. They have not been available as new parts for decades now. The new type bridge rectifiers are easy to install. I used one of the new plastic case types with current rating beyond the original part and heat-sinked it to the side of the chassis using some of the white type compound.

I see that someone had installed a tubular 40mFd capacitor to replace a bad section of one of the can electrolytics. You are doing things right by replacing the entire can with a new one of correct ratings per section.

Keep us posted on the progress.

Joe

 

[ncwalz]

Will do, thanks.

 

[larryderouin]

ncwalz; As you have a late version, the RF tubes are very cheap in price. I'd go ahead and get a complete replacement set, as the originals are showing weak, but are still probably servicable. Here's the prices that one of the suppliers I get tubes from, has for the RF/IF tubes for the 400.
www.abcvacuumtubes.com
6HA5---------->$4.00
6AB4--------->$3.00
6BA6---------->$4.00
6AU6 x3----->$4.00ea ($12.00)
Total.....$23.00 +7.95 shipping. for $30.95 Grand total.

And you can specify the Brand, (provided they have them.) For RF/IF tubes I like GE tubes. I've had really good results with them, and they tend to live longer than anything else for some odd reason.

The two I would be really concerned about are the 6HA5 and the 6AB4 These two are the hardest working of the 6 tubes. Plus when in any position other than FM, either the heaters are turned on but no B+ to the tubes or they are shut down, or something like that. Dave knows exactly which and how for the RF/IF Tubes in the late version.

 

[ncwalz]

Thanks Larry. For that price I will replace all of the weak tubes.

 

[larryderouin]

I did basically the same thing for my Grand-daughter Annie for her 1st birthday. I had a KLH 20 (with the speakers) and was going to just replace the power supply caps and what ever needed replacing. Figured she'd use the heck out of it so I replaced every cap in it, plus better output transistors, replaced the slide switches with FISHER Long handle types so she could work the power and Stereo/mono switch, new idler wheel, 2 LP and 1 78 needle, resealed and re-capped the x-overs. She uses it 3-4 days a week now that she's 4 years old, and even took it to Pre-K for show and tell. She's got her own records (5-6 Disney and some various 70's Rock stuff I had extras of, plus the obligatory H.A. and the T.J.B. which she loves) I go thru it yearly for her right before her birthday, and it gets used during the party.

 

[The Fuxtor]

I used one of the new plastic case types with current rating beyond the original part and heat-sinked it to the side of the chassis using some of the white type compound.

One of these type?? I received one from a metalbone kit, but wasn't exactly sure how they were installed.... I actually have a late model 400 with the plastic bridge rectifier with the fins on the back, so i probably am not going to bother replacing it.

 

[larryderouin]

Fuxtor; That bridge would be attached to the side using a small screw, and nut. Near the legs on the front you'll see a mark just above each leg.....like this + ~ ~ -, OR - ~ ~ +. You would find the sam marks for + and - and attach them to the corresponding legss on the new bridge. The other two (marked ~, for AC) are interchangeable. If you don't plan on it now while everything is open, put it in a small plastic bag and tape it securely inside the unit.

That one is probably a 4A which is a bit overkill which is good. I like the table legged shaped ones as I have the whole body between the chassis and the leads and it's rated for 8A. Way overkill but it's not even breathing hard.

Larry

 

[The Fuxtor]

good idea! I did the same thing with a pot replacement for my Adcom gtp500 II preamp/tuner. Ordered 2 replacements, and kept one stashed for the future inside.