The Fisher 202-R Tuner

Thanks, Tubologic...I will clean the contacts (but not with abrasives). All electrolytics, including the one you mentioned, have been replaced. Well...all except the three that go in the FP can.

Speaking of which...

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The can is open! It was not easy grinding that flange off. Now, without the rubber seal, the terminals do not want to stay in place. :idea: The terminals stay in place better if I include the wafer disk that was originally behind the rubber seal. Now to decide whether to glue the two wafers together with epoxy, or let the friction of the newly crimped can (once I reinstall everything) hold it all in place. I do not want to use J-B Weld because it can be conductive...not a good thing with high voltage.

And...not only did I get the FP can open...but I also received my replacement slide switches!

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Other than the handles being black instead of reddish brown, these switches are the same as the originals.
 
done that before too. I want to say there were two main makers of those slide switches, and the internals are slightly different. Switchcraft is still making them the same as they have forever, but I forget who the other was. I just seem to recall they don't quite interchange, something about the way the friction springs sit being different. I know my Sherwood uses the "other" switch, and the friction spring that makes it click into position is broken on one of the switches. It doesn't affect anything but the switch doesn't have a solid feel.
 
Ron;

You made a good score with this 202-R tuner. It is one of the best and having the metal cabinet helps protect it from damage and RF interference at the same time. I have a metal cabinet with the X-101-C I restored.

You are off to a great start on this restoration. Glad to see you here as well as on the Philco Phorum and Antique Radio forum. This is the group to participate in for Fisher restorations that has the best expertise that I have found.

I am still in process on adapting my Metropolitan 16A cabinet to house the 800B that I have restored. Right now a few bits of wood that were knocked off of one door accidentally are in the process of repair. As soon as the glue is dried sufficiently I can put the door back on and get the other issues done such as mounting the coaxial 15" speaker I constructed and adding the bass reflex port on the back, then sliding the radio tuner and power supply in and doing the final fitting and fastening. Do you still have your 800B?

Joe
Cabinet with polished brass web.jpg Cabinet Doors Open web.jpg 800B trim panel fit web.jpg Changer Installed.jpg
 
I will find out soon whether or not I can install the old handles on the new switches...probably this weekend. I did buy extra switches since they were cheap, so if I mess one up...no big deal.

Here's where we are at with the FP can:

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The two wafers have been glued with clear epoxy, and they have to remain clamped overnight.

Meanwhile...here are the new Nichicons which will be going inside the can:

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Small in diameter...small enough that three will easily fit inside the can with room to spare.
 
Joe (audmod01): Thanks! I have never owned a Scott 800B, but I do have a 33-tube FM Philharmonic (early FM, 42 to 50 mc).
 
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I recently attempted to replace a rocker switch on the Heathkit AR-15 receiver. Could not find a proper size rocker so I bought a slide switch and attempted to do the disassembly and swap, keeping the rocker portion of the old switch. Parts were not interchangeable. So, I ended up swapping a different switch (maybe the mono-stereo, or muting, don't remember) into the power position since the other function is rarely needed. The power switch was a DPDT and it had already been turned over to use the other contacts.
 
I have a Scott 800B. I also have an Allwave 15 and an SLR-12B.

Honestly I've never really had a lot of luck rebuilding cans. Its another one of those fussy processes that I sort of hate, right up there with re-foaming speakers and replacing heater cores in cars. I have done it, and if absolutely needed I will do it, but I do not enjoy it. I also dislike it so much I won't even do it for other people :) The bathtub caps in my Scott 800B and the tar box caps in my Fada and Atwater-Kent are right up there on my list of things I have little desire to do again.
 
Gadget, for me, the FP can rebuild is a challenge. I've cut them open before but this is the first time I have ground the flange off and pulled the guts out from the bottom. If this works out OK, then I may very well continue to rebuild FP cans in this fashion. I won't do it for anyone else though.

Hey, if this FP can turns out OK, I might even rebuild the cans in my Fisher 400 instead of going the Hayseed route.

I have years of experience rebuilding Philco bakelite block capacitors, Philco's metal can capacitors, and the older stud mount electrolytics, so I don't mind trying an FP can.

You mentioned Atwater Kent tar box caps. Do you mean the flat rectangular ones held in place by two screws and nuts? Getting the cover off is a pain...but once you have them open, they are easy to restuff. Plus, there is no need to put the cover back on as the back side is not visible once the can is remounted in the chassis.
 
My 39-116 had I think two of those blocks. It wasn't so many that I grew to hate it but I can see how it could get maddening.

The tar box ones are the big metal box used on the 20s sets for the main filter caps. They were paper caps potted in asphalt. My 1929 Fada used the same thing. You have to heat it enough to soften or melt the tar, pour most of it out, and then dig the caps out. A-K also potted their interstage transformers in the same stuff, and its the same process to rebuild them when the transformers fail. Once empty you don't have to re-pack them at least. I used a torch with the Fada and just repainted it, but for the AK 20 interstages I found a crappy pot and hot plate to rig up what amounts to a double boiler in order to melt the tar followed by a mineral spirits wash to get the thing totally clean.

I know the metal flat ones you speak of though. Very similar to the bathtub caps in 40s gear, melt the solder to get the lid open and then restuff. I put the lids back on mine but with just a very small dab of solder to hold it in place.
 
Gadget

Oh, those...

I feel your pain. I have a cheap Harbor Freight heat gun which sees very little use, and I bought it just for such tar-filled paper capacitor cans. I do that sort of work outdoors due to the heat and the mess involved. I would not want to do that sort of thing very often. No, it is not fun.
 
And so...

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With the two wafers glued together, I began the process of restuffing.

I attached the three common negative leads to a black wire which I ran through an unused hole in the wafers.

Then it was time to put the new electrolytics in the old can...

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and then make a new flange as best as I could...

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Is it perfect? No. Does it suit me? You betcha! :thumbsup:
 
The FP capacitor can is now back in the tuner:

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I have started reconnecting the various components to the electrolytic terminals. For the common ground lead, I soldered the wire to one of the twist-lock terminals - the same one which the yellow 0.1 uF film cap is soldered to.

I'll work on it some more over the next couple of nights, and then comes the next big thing - replacing the old Siemens selenium rectifier with four silicon diodes.

My sincere thanks to arts for giving me the idea to rebuild the FP can in this manner. I think it turned out much, much better than I expected it to. It was neat to learn a new technique which I will be using in the future.
 
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Looks good Ron. Mine all turn out like that. Unless you have a press with a flange bender, you won't get it perfect. Close enough is good for what we use them for and you won't see the flange anyway once it's mounted.

Larry
 
Nice work on the cap Ron. Most first attempts (in my case at least) don't usually turn out that nice:)

I have a foot operated manual rivet press for installing the tubular rivets like the ones used in your tuner. One of these days I'll have to machine a holder and flanger set for it so I can do this cap thing the easy way.......you know....one of these days.....

By the way,love your avatar! Most people don't realize that Red Green is Canada's version of Uncle Sam.:rolleyes:
And I'm a Philco fan also; I have a 1933(?) model 19,and I'm rather good with Predicta's as well.
 
Ron -- For most Fisher tuners, when the selenium rectifier is changed out for silicon, you will need to place a 100Ω 5W resistor between the output of the new bridge rectifier and the first filter cap, to maintain the original B+ levels. This is a new resistor in addition to the original dropping resistors which remain in tact and unchanged in value.

Ya tuna's lookin' good!

Dave
 
Dave

I was aware, but thanks.

And wouldn't you know it...I thought I might have one or three 100 ohm 5W resistors kicking around, but I can't find any. :( So...I guess that when I try it out again, I'll be running it on the Variac at somewhat reduced voltage, until I make another Mouser or Digi-Key order.

So anyway...

How does that rebuilt FP can look from topside?

Not too bad...

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And now, after seeing these photos, I realized that I normally polish these aluminum cans with Mothers before I reinstall in a radio...and I forgot to do so on this one.

I have pulled the old selenium rectifier...

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...and installed a terminal strip which the individual diodes will be connected to.

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We're getting close to the home stretch on this one, other than the 100 ohm resistor I will have to order. This weekend I plan to install the two new switches in back, install the new diodes with a temporary jumper wire in place of the 100 ohm resistor, and try it out!
 
If the output voltage on that rectifier is good, you can run it until you get the resistors.

Maybe I like to live a little on the dangerous side, but I really haven't had the awful problems with selenium rectifiers that people say they do. I've had one of that flat pack shorted, but it came to me that way. The US finny style, I've had a couple with really low output voltage but none ever exploded and killed the neighbor's cat or anything.

I get that they don't last forever but I really wonder if their reputation for problems is a bit over-blown.
 
I don't normally put in the resistor to drop everything. B+ voltages are within 5V max. and Bias Voltage at the caps is approx -24 to -26. Which with Tung-Sol Re-Issues helps with them being a hot biased tube. Also it gives me some headroom with the 7868's the same way. The lower side (toward zero) with an IBAM/IBBA will usually allow only -13 to -14v. Which is a good number to limit bias at the lower side(toward Zero). With very worn 7868's they can run 1/2 way comfortably @ about 28ma max'ed out (these are my test mules). With the late model 400's the B+ is still within FISHER's variance of 10 to 15% + or -. But usually no more than 5v off ideal.

I do put a 100 to 220ohm 10w(adjust to get -12.3v on the 12ax7 heaters) on the heater line with a 220uf 100v cap and that keeps the heaters in line. I take the heater line right off the rectifier instead of the cap. No special reason but with my facing the caps to the center of the unit, it makes for a cleaner look.
 
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