While awaiting my transformers back from Heyboer (the speakers came yesterday from Sound Remedy) I decided to take a quick look at my Hippo. I bought it this winter, or around, and cheap - about $60. Very clean unit.
With an excellent original back etc.
Now, the first thing I need to ask - what's the least painful way to extractthe chassis? I realize I need to desolder the antenna, but I am concerned with the dial string assembly: is there a way to remove the chassis such that I don't ruin it? I thought of taking the pulley off the tuning cap and tape the string to it but the pulley is pressed to the shaft, no screw.
How did you guys do it, or did you have to bite the bullet and restring it in the end?
http://www.nostalgiaair.org/pagesbymodel...013634.pdf
Mike,
I'm trying to remember how it disconnects, I think it has a setup where it's pulled by a spring on one end, and the dial cord on the other, by that big drum pulley on top of the tuning condenser, so you slip the cord off the back of the pointer somehow. It's been a few years since I dealt with a hippo, but I can pull one out of storage and have a look.
Regards
Arran
Thanks, Arran. I'm sure it's simple but it isn't obvious, and I'd like to minimize the possible PITA when putting it back together.
OK, it is very simple. Just taped the cord to the pulley so it stays in place and it is released by simply pulling the hook spring on the pointer.
Now desolder the antenna and this is it.
Not bad, rebuilt the triple electrolytic.
Used dual 12uf 170mA 45V caps, they fit well inside the tube. I ended up with all three being 24uf which is (should be 30, 22, 20) OK.
Tomorrow will try to restuff the tubulars.
I knew you could do it Mike!! Like Arran I did one many years ago and just couldn't remember how it comes apart.
It's easy when you know how!!
I hope if nothing interferes tomorrow, I'll be able to finish the recap.
There has to be at least one bad tube as the power wires show open while the power switch is closed.
Will find out.
Mike; Terry;
I had a look at one of my Hippos last night, the cord that moves the pointer has a loop on one end that fits over the hub of the pulley on top of the tuning condenser, and then feeds out of one of the slots in the pulley, and then over to the clip on the back of the dial pointer. I don't know what was on the end of the cord where it clipped onto the back of the pointer as that end had apparently snapped off and disappeared, but it was probably a knot to keep the cord from slipping through. It's actually a fairly ingenious dial cord arrangement, they found a nice and simple way to move that pointer rather then going through some Rube Goldberg arrangement of pulleys and loops like some British or European radio would use.
Regards
Arran
Whew! Finished the recap and changed 2 or 3 resistors that were off too much.
I don't know if someone did some repairs, all looked factory to me, but the wires are as new, so no wire replacement had to be done.
I will power it up (provided I have all tubes) some time this week.
Mike;
Since it's a 1948 model, Philco had probably switched to more modern vinyl wire covered wire by then for everything rather then mixing and matching with the rubber/gutta percha covered wire. About the only shortcoming regarding later Hippo production was the introduction of those mini IF cans on some production runs with the junk silver mica caps inside.
Regards
Arran
Oh, forgot to add: there is that "special" cap, 0.2uF that is "polarized" and used as a 465kHz trap; I obviously did not have that one and I did not know the number of turns it would take if I decided to make it a "coil over cap" trap, so I rejoice in the fact that, restuffed with 0.2uF, it will look original and will act as the chassis-to-common tie cap, and as for the trap, it is no longer the issue anyway and is not needed. (It is the C19 as shown for code 121).
So, good news is: all the tubes test good. The open circuit was due to one of the 7B7 loctals having oxidized pins, so even after testing well on the tester it would not complete the circuit upon the re-insertion, at which point I simply scraped the pins and then it worked out.
I brought it up on my Variac, saw the pilot lamp coming on, simply waited for the tubes to glow, spun the tuning cap pulley, and without the loop antenna connected got my local station where I expected it. It plays nicely, no hum.
Now the chassis need light dusting and the case need some cleaning and maybe polishing.
Some pics:
Before and after recap:
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Very nice job.
