[TV MAN]

Well, first off, this may or may not turn into a restoration until I can find all the needed parts. I honestly bought it 1. because the chassis was not moused, 2. I took a chance on the transformers, and 3. I kinda like the old Fishers. Worst case, it becomes parts or sits on a shelf until my estate sale 

Now, the task at hand: Bring this back to life! You can see from the pictures, it came missing all the tubes (it was described that way), and knobs. The seller did a very good job packing it, so it arrived intact, unlike a couple others that didn't fare as well. I could have spent way more money and bought something that included tubes, knobs and cabinet. But, most likely I'd still have to replace a bunch of tubes and do the recap, etc. The front panel isn't too bad, a few light scratched and dings that wouldn't be seen in a cabinet, no rust and it looks original, so no failed resto attempts. Dial cord is intact and power switch works.  

   

At a minimum, I have something to start with. I had enough tubes on hand to to populate most of it, but was short the tuning eye, one IF tube and a pair of outputs. I did find a sub for the IF tube,  but only had one pair of bulbs for the output and had to borrow those from my instrument amp. I knew it had been plugged in by the seller and saw the dial lights on, so I knew there was some life in there, but no idea how much, or if the output transformers were good. I brought it up with one pair of output tubes, kept it on the dim bulb and voltage down, and here are the results as of now:

Some previous resistance checks showed continuity on all windings of the OPTs, no shorts to the chassis, and the main filter cans looked intact. I did an initial 50v tubeless power up, then to 90v and no smoke, . All voltages were present, although I think the -bias on the output tubes was a little off, and noted it got higher (less -) as it ran. The bias filter cap shows signs of - yuk! All tubes lit, and after some coaxing I did manage to get a signal coming through on the R channel! I switched the tubes over to the other channel and same. I can get a signal through, so I believe all the iron is good. I could also get a signal from the phono input on 1 channel, but the FM is dead. I could hear a very faint hiss with the volume control all the way up, but no stations. The plastic wheel on the tuner is broken, so I only went so far. I suspect the good ole' silver mica disease, but need to make some more checks. As of right now, that's as far as I got. It is an earlier production according to the serial number, and I don't have the service info on my bench. I did find a pair of NOS 7868 tubes, so I can at least run both channels at the same time - if I rob from my instrument amp again. 

I went NOS because I read the pin diameter on the EH ones were bigger and would ruin the sockets, and I'm trying to keep it stock. Figured it's be better to search and wait rather than be changing sockets. This will probably not be a rapid project and will work on things as I find parts, time and see just what is there. 

   
   
   

[MrFixr55]

Hi TV Man,

I have a 400 and an 800. I found them on the street within 2 years of each other about 30 years ago. Both work, but I do need to get through them. One strange thing that occurs to the 7868 output tubes is that they crack at the base. I had one bad one so I went to an old Bogen PA amp that I have that has 4 of them. 2 were cracked also, and, of course, all cracked tubes lost vacuum.

Someday, I will sell the 400. The 800 is a keeper because it has both AM and FM (from when they first experimented with stereo by sending one channel on AM, the other on FM), and FM MPX Stereo.

I haven't played either of them for a while, but the last time I did, neither had SMD.

Good luck with yours. I would definitely consider getting rid of the selenium rectifier, as I believe that it also powers the preamp 12AX7 filaments in addition to providing the C- for the output stage. I would also consider "fusing" the output tubes by putting 10 ohm 1/4 watt resistors between the output tube cathodes and chassis ground instead of the cathodes directly connected to ground. This may save the tubes or OPTs if you lose C-.

[jrblasde]

If you make it a project, the parts will come. I say this because I’ve been there. I bought a Philco 46-480 and made it halfway into the restoration before I realized that I was missing the ratio detector coil. The odds were against me; that coil was unique to only the 46-480. I called, emailed, and wrote to folks all over the country. It took a couple of months, but FINALLY one great day I was surprised by a phone call. Mark Oppat of Old Radio Parts found a new one.

The call is yours, and it ultimately depends on how much you want to see it restored. To me, the 46-480 was my first ever console radio and I really, really wanted to see it happen. But you may not have too much money or desire invested into this one.

[TV MAN]

A little patience will pay off. I found a pair of NOS 7868 bulbs, RCA, and got the EM84 eye tube, along with a couple other less exciting bulbs. I found a 'maybe' on a cabinet, but so far, knobs are eluding me. Probably something will pop up when I lease expect. At least, not I can bring it up with all 4 big bulbs and get a better feel for what I have.

[TV MAN]

Well, I have some knobs on the way. They are repros, and looking at the pictures, they are close. They lack the brass rings on the inside knobs, but have the brass ends. When they arrive, I'll see how they are. Don't need perfection, but hopefully they will fit and look about right.

[morzh]

Best is the enemy of good enough.

[TV MAN]

Welps, I found me some knobs. They aren't bad repros, and few would ever catch the differences. Fit is "ok". Some are really tight, one for the tuner shaft needs hogged out some, but It's not the sellers fault. The 500c has a shorter shaft than a 400, or this one anyway. I showed the pictures of the knobs with some original, and they are close. I think the most notable difference is the repros don't have the brass rings on the inside part of the knobs. They look pretty good overall. If you're a purist, then these knobs wont be the ones you want, but they sure are better than the nothing I had! 

   
   
   
   

[radiorich]

Hello Tim,
I need to check my collection to see if my Receiver is a 400 too.
I think Those look nice and they look darn good .
My Fisher was running a pair of Jensen Coaxal Woofers it was built into the wall of a house I plan to build some nice repo early cabinets for mine .

Sincerely richard

[Arran]

Tim;
Are those knobs 3D printed? I think you could probably add the trim rings later if you had a small lathe, and some donor knobs from something else like a junk TV, but I don't really see the point. The knobs that impressed me where those wood ones someone was repopping for 1930s Brand Z sets, wood knobs, not plastic. I have heard someone is reproducing wood Rogers/Deforest Crosley knobs but have not looked into it further. It would be nice if someone would reproduce the 1940-42 Rogers ones, they were made out of Tennite plastic and like to deteriorate.
Regards
Arran

[Arran]

Tim;
I think that some Rowe/EMI jukeboxes used those 7868 tubes, they seem like the answer to a question that never really needed to be asked like a lot of later tube types. I told a friend that if the ones in his AMI Diplomat are dead we are running 6L6 tubes (or 6V6s) in their place, which is what most tube guitar amps used anyhow, and still do. The only new ones that made sense were the Compactrons G.E developed as they cut down on the parts count, and were even logical at times.
Regards
Arran

[TV MAN]

Thanks Rich! I haven't found anything even close other than originals, which do pop up from time to time, but most sellers are rather proud of them. I stumbled across these and the price was reasonable, not cheap, but not bad for a set. They are 3D printed, but probably won't worry about the brass rings. They came as a set of 8 for a 500c, so I have a couple left over. I'll ask the seller if he's going to keep making these, and if so, I'll post the info. I'd like another set myself to have on hand. Seems the originals like to fall off or something.

I've seen a few amps for sale from a jukebox and Conn organ that use those 7868s. I suppose it was a "modernization" of the layout, maybe was a little cheaper to produce at the time without the octal base or something. Who knows. I've read that they are run pretty conservative on these and tend to last a long time. In the future, if I ever come across another, I'd probably switch sockets and run 6L6, 7591, 6CA7 or something. I do believe the primary impendence is a little higher in these, so 7591s might be happier, but we all know that a 6L6 will run about anything you can connect them to 

I do believe the Compactrons have their place too, but since they were mainly for TVs, they can be a little different. Thought about trying some on an amp build driver where I have limited space, but a big drawback would be the fact that they are no longer being produced, so a couple spares would be needed on hand. 

This project is getting interesting and building steam! Setting up for a father/son project at the moment. Look for a thread on that 

[radiorich]

Hello Tim,
Yes, even with solid-state components like transistors, it’s smart to keep spare parts, and I know RCA used those Compactrons in their TVs.
Sincerely Richard