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 Post subject: Philco Model 80
PostPosted: Mar Sat 31, 2012 12:08 pm 
New Member

Joined: May Sat 15, 2010 11:56 am
Posts: 8
I've relied on this forum for information and insight for a while now.

I don't mean to waste anybody's time here, but I do want to thank you for threads on the Model 80 set. Also, information from the Philco Repair bench website has been very much appreciated and useful.

After replacing all of the capacitors, and all of the resistors (except a big 5W resistor that I didn't have that is off by only 12%), and finally rewinding the 'tickler' coil, I have the set running, but only getting the three local stations at the low end of the AM band.

I'm hoping that an alignment will bring the radio up to full operation, and have decided to buy the necessary equipment from this forum.

Thanks to all of you here for your help. It's been a lot of work, but I have really enjoyed it. You experts here would have likely fixed this set with your eyes closed, but for my limited, but growing aptitude, this was a real challenge.

I will not give up on this old, old set.


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 Post subject: Re: Philco Model 80
PostPosted: Mar Sat 31, 2012 12:11 pm 
Member

Joined: Aug Sun 01, 2010 1:12 am
Posts: 6756
Location: Minnesota
Nice work. It feels good when they work doesn't it, even if they still need work. I'm not the worlds greatest alignment person so I'll wait for others to chime in but congratulation for your persistence. Most of us started this same way.


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 Post subject: Re: Philco Model 80
PostPosted: Mar Sat 31, 2012 8:13 pm 
Member

Joined: Feb Wed 25, 2009 4:06 pm
Posts: 1023
Location: Morristown, N.J.
You really need a scope to see if the oscillator is working across the entire band; from what you say, it sounds like it isn't- and that takes you back to the tickler winding. The only thing I can suggest is to reverse the tickler leads; you may have wound it backwards on the form (easy to do) and reversing the leads will fix that quickly.

You really need a scope at this point.

Pete


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 Post subject: Re: Philco Model 80
PostPosted: Apr Sun 01, 2012 1:24 am 
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User avatar

Joined: Jan Mon 18, 2010 2:13 am
Posts: 8435
Location: Dayton Ohio
The 80 is a nice radio, though as a little 4 tuber, it won't have much performance without a good outdoor antenna. Say a 75 foot or more wire strung as high as possible.

I had a similar version (model 84) and couldn't get much out of it without an outdoor antenna.

-Steve

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Consoles and floor models, the bigger, the better!


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 Post subject: Re: Philco Model 80
PostPosted: Apr Sun 01, 2012 6:37 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 15839
Location: ID 83301
How did it work before you replaced all those parts ? It is a bad idea to replace all of the capacitors at once and a worse idea to replave every resistor . Some schematics are wrong or hard to read . Some radios especially the low tube count ones many times need one or more of the resistors value changed a bit for better preformance .

I dont know your exact situation and maybe an alignment will fix it but i would stop replacing so much stuff . About all you should need is a signal generator .


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 Post subject: Re: Philco Model 80
PostPosted: Apr Sun 01, 2012 6:56 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 10788
Location: Valley City ND USA
Hi JBN. I don't want to lead you astray, but have you tried slight "tweaks" to the assorted
trimmer adjustments? Just move slightly in both directions to see if volume increases.
Be certain to return them to original position if no improvement is noted. Your tuning cap
has them too. The latter brought one of my 4 tubers up nicely. You don't have test equipment,
but you have your ears.


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 Post subject: Re: Philco Model 80
PostPosted: Apr Tue 03, 2012 4:19 pm 
New Member

Joined: May Sat 15, 2010 11:56 am
Posts: 8
Thanks for the replies. My answers:
(1) The radio was a gift from my parents and has been a knick-knack for years. The cabinet is nice. The radio never played. Well, more accurately, I never tried it. I wanted to ensure that I did not 'smoke' the set.
(2) This forum allowed me to obtain schematics (the old Rider's information) and when I first got under the chassis, I was disheartened to see that numerous bakelite capacitors were gone and several repairs/rewirings had occurred. So, I began at the plug and systemmatically verified the wiring and replaced components along the way. While doing this, I found what I initially thought were wiring errors, but careful examination of the documentation revealed that changes were made in the radio's wiring during later 'runs'. Eventually, I got the entire schematic verified as correct. During this effort is when I found the open tickler coil. I rewound the coil (per instruction from a thread on this forum). I also reversed the leads on the tickler coil when I only received two stations - that didn't improve the situation.
(3) The oscilliscope comment is much appreciated. I have purchased a signal generator and hope to get it in a week or two. Perhaps an oscilliscope will be my next purchase. Your comment made sense and could be the ultimate trouble here. Thanks for the insight. "There is no substitute for experience".
(4) I have fiddled and fiddled with the four adjustable capacitors on the chassis back and the two on the tuner. If there ever was a time when I felt like a dog chasing its tail, this was it. The Rider's manual has fairly straightforward alignment instructions. So I decided to obtain the signal generator. It really helped when one presented itself on the sellers forum here. A comment on the sale thread read (to the effect) 'that is a nice signal generator, if I didn't already have two I would buy it'. That type of a recommendation sealed the deal for me.
(5) Right now, the radio is reassembled and returned to its knick knack position. It is nice to know that I could plug it in and tune to the two stations it receives. But I'll await delivery of my new signal generator, and get back at it. I will not relent until the radio works wonderfully. If this requires obtaining an oscilliscope, then that will be the next step. I'm not going to give up on this.

Thanks for the comments, and I'll keep you apprised of the progress.


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 Post subject: Re: Philco Model 80
PostPosted: Apr Tue 03, 2012 7:36 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 467
Location: San Jose, CA, USA
Hi - One quick thing to check before buying a scope. If you're only getting reception at one end of the dial - check the tuning capacitor to make certain someone hasn't inadvertently bent one of the outside plates. If the plates short out as you close that capacitor - reception stops. A good visual check and gentle rebending will suffice. Has happened to me more than once. Best of luck, Tom


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