Trav-Ler model 5170

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Trav-Ler model 5170

Post by Wildcat445 on Sun Aug 24, 2014 7:02 pm

This cheap little clock radio has been in my junk pile for eons. I have no idea where it came from or when I got it. It is in semi-horrible condition with its fake wood graining peeling. My wife was helping me clean out the garage and we came across this thing. The frau thinks it is cute, so she wants me to fix it. I made a note on it who knows when that it had a dead oscillator. I pulled the chassis out and all the caps are original. So I changed them. The chassis on this thing is like four inches square and working room is pretty tight. The oscillator is still dead. Voltages are pretty close. There is 0 volts on the grid of the oscillator, so the oscillator is for sure not running. I subbed the converter tube three times, with no change. I subbbed the 12BA6 twice with no change. The saving grace with this little set is that it does not have slug tuned IF transformers, thus should not have SMD. My next step is to get out my signal generator and see if I can get a signal thru it. The oscillator coil checks okay. Both IF transformers check okay, as in not open. The power supply and audio sections are functioning normally. Sometimes, these things are just plain dead. I had another 5170 that was nicer, but did not work any better.

WC

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Re: Trav-Ler model 5170

Post by Bill Cahill on Mon Aug 25, 2014 12:19 pm

Even if it does have smd, that shouldn't kill the oscillator. Look for bad mica capacitors, and, resistors, plus poor connections, bad solder joints. A shorted tuner oscillator plate could also kill the oscillator.

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Re: Trav-Ler model 5170

Post by 75X11 on Mon Aug 25, 2014 4:07 pm

Could you share a pic or 2 while you are treating the patient?
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Re: Trav-Ler model 5170

Post by Wildcat445 on Mon Aug 25, 2014 9:41 pm

Thanks, Bill, I am in the process of checking those things now. Solder joints and such seem okay. The e-caps are wired correctly. I used my signal generator, and got a signal thru the radio to the speaker. I attempted an alignment. This procedure actually went well until I tried to peak the transformers for the second time. Right at the spot where the trimmers peak, it starts motorboating. If I back off, or advance a tad, the motorboating stops. It does this with both IF transformers. The radio sorta works, but only on my long outside antenna. It does not receive a station at all on its loop antenna. Very weak even with the long antenna. When I try to peak the oscillator, it motorboats on peak. The alignment instructions for this set say to set the tuning cap to minimum capacity. Normally this is set to maximum capacity. I have overlooked a weak component somewhere. I am checking resistors first, then micas. There is not much in this set to go wrong. There is only a handful of parts. No room for much else. When I started tinkering with the IF cans, the oscillator took off. What's up with that? I am sure that I have the generator tuned to the IF, not a harmonic, and I checked the frequency of the signal generator, and it is exactly 455khz. You are supposed to set the generator to 1650khz and then peak the oscillator trimmer on the tuning cap to that frequency. There is no alignment to the lower end of the dial. I can't tell if it tracks properly, but the stations it does receive are approximately at the right spot. Another weird alignment instruction is that it says to connect the ground connection of the generator to the frame of the tuning cap, not B-. Have you guys had experience like this before? Motorboating usually means, to me at least, inadequate filtering of the output filter cap.

Sure, 75, I will try to get some pics to share. I'm committed tomorrow, so it may be a couple days. Thank you both for your input here.

WC

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Re: Trav-Ler model 5170

Post by Bill Cahill on Mon Aug 25, 2014 10:12 pm

The motor boating isn't the oscillator taking off. It's feedback. Your oscillator, or, antenna rf , or, both, isn't working. Look for shorted, or, leaky micas, and, ohm meters won't tell you, bad resistors, one, or, more shorted tuner plates, and, you are trying to adjust the oscillator wrong. It should be at 1625 KC. Further, is the radio 455KC, or, something else?? There were a lot of differtent IF frequencies used by manufactuerreres Including 462KC..

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Re: Trav-Ler model 5170

Post by Wildcat445 on Mon Aug 25, 2014 11:16 pm

The IF is 455 khz. What is feeding back, and from where, do you reckon? I wonder about putting the ground lead of the signal generator on the tuning cap frame. Normally, they want that lead on B- to prevent oscillation. Wonder if I moved the ground lead of the generator to the chassis or to B-. Would that have any effect on the feedback and the motorboating? Seems like I have run across this before, but my mind is drawing a blank on what the problem was.

I had a VTVM monitoring the oscillator voltage on the converter grid. The oscillator started running when I started turning the IF trimmers. Before it started motorboating. Why would adjusting the IF's have any effect on the oscillator? That I do not understand.

WC

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Re: Trav-Ler model 5170

Post by Dr. Radio on Mon Aug 25, 2014 11:24 pm

Hmmm. I think they built some cheap sets... I'll think about this one...
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Re: Trav-Ler model 5170

Post by Dr. Radio on Mon Aug 25, 2014 11:25 pm

Does it have the domino dot micamold caps in it ?
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Re: Trav-Ler model 5170

Post by Wildcat445 on Mon Aug 25, 2014 11:43 pm

Yes on both counts. It is a cheap set, and it has domino dot Micamolds in it. A couple I think. I will get some pics in a couple days and we can share them. This thing certainly worked at one time. Maybe I can make it work again. It's not much of a radio, but I feel silly having a problem with something like this, when I can tear a Magnavox stereo completely apart and make it work just dandy.

WC

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Re: Trav-Ler model 5170

Post by Bill Cahill on Tue Aug 26, 2014 11:17 am

I can guarantee those mica molds are no good. Reeplace them with new proper mica capacitors. Do Not use disc capacitors, as most have an 80 percent tolerance, plus, minus.

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Re: Trav-Ler model 5170

Post by Dr. Radio on Tue Aug 26, 2014 9:04 pm






Beitman's had a rather poor quality to work with on this one, 'Cat.

Very simple, basic receiver.

I'm a bit confused. The notation indicates the "ANT" trimmer is apart of the rear loop antenna? But the trimmer is pictorially shown on the tuning gang where you would expect it. ?????


Verify those connections and change the 50 pF mica in the OSC circuit for starters.
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Re: Trav-Ler model 5170

Post by Wildcat445 on Tue Aug 26, 2014 9:52 pm

That is the same scan as in Riders.  The service literature mentions the antenna trimmer on the loop antenna, but there is no such component.  I got the motorboating to stop by moving the ground lead of the generator from the frame of the tuning cap to the chassis.  I can peak the IF's now.  I do not have the correct values for the micas.  I have 110 pf.  One is 50 and one is 220.  The radio will work on its loop antenna now, but its performance is nothing to brag about.  All I get with it connected to my long antenna is louder noise.  I'm going to order some micas and change those, then recheck operation.  This little set is the most basic of basic, but sometimes they can be the toughest for me to get to work correctly.  Although the alignment instructions are not clear on this, I radiated the signal at 1400 thru the antenna to peak the ANT trimmer.  It is still not 100% on alignment, but I need to run a bug to ground, then touch up the alignment.  Thanks, Doc.  Bill, thank you for the heads up.  Correct mica caps, not discs, it shall be.

WC

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Re: Trav-Ler model 5170

Post by Bill Cahill on Wed Aug 27, 2014 10:32 am

Another heads up. When using a signal generator on anything off line, that is without a power transformer, you always need a .01 630 volt cap between ground of generator, and, B-. Direct connection could cause a line short, with severe damage, and, it definitely causes a shock hazard.

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Re: Trav-Ler model 5170

Post by 35Z5 on Wed Aug 27, 2014 11:24 am

If it has the IF cans pictured it won't have SMD as the trimmers are the caps...
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Re: Trav-Ler model 5170

Post by Wildcat445 on Wed Aug 27, 2014 12:53 pm

Bill, I put a permanent isolation cap in my signal generator, and still use an external one just for safety's sake. I am running this chassis on an isolation transformer, and still use an isolation cap in the ground lead. You are absolutely right. You cannot be TOO careful when working with a hot chassis like this one. Reminding everyone of that is a good thing.

WC

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Re: Trav-Ler model 5170

Post by Ragwire on Sun Aug 31, 2014 12:08 am

You hit it on the head that the simplest radios are often the worst to get working properly. A complex, high end radio tends to be more stable and each stage has a discreet function without a lot of overlap in functionality. The little AA5s seem to be balance on the edge between low cost, minimum components and breaking into oscillation or other maladies. I have spent hours sometimes fiddling with the little AA5s. I love them though.
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Re: Trav-Ler model 5170

Post by Wildcat445 on Sun Aug 31, 2014 2:19 am

I have tinkered with this little thing. I did probably the alignment ten times to get it peaked. I have some new mica caps ordered for it, so those should help. I have it playing on its own antenna, but it will never be the best radio I own. The frau thinks it's cute, so she wants me to hotrod the cabinet, then it can collect cooking grease by setting up on the cabinets like the rest of "her" radio collection. It IS cute in its odd sort of way.

WC

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