Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Nov Thu 23, 2017 4:36 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 55 posts ]  Go to page 1, 2, 3  Next
Author Message
 Post subject: Hallicrafters model 505
PostPosted: Oct Thu 23, 2014 5:37 pm 
Member

Joined: Oct Thu 23, 2014 5:15 pm
Posts: 37
Hi everyone! I am new to the forum, and have a few questions that I hope someone can help me out with.

I was given this set by my next door neighbor. It had a shorted power cord which I have repaired, and was missing the 1B3GT rectifier tube. I believe the original owner attempted to repair it to no avail. A close look inside revealed several areas where there were large globs of solder with leads of components stuck in them. I can't imagine a tech doing this! Many of the paper caps had bulging ends and one had an end blown out. Having built several tube guitar amps, I decided to replace all the e-caps and paper/ wax caps with new parts from Just Radios before powering up the set.

I have finished re- capping today, and decided to power up the set on a dim bulb tester. All the tubes were installed with exception of the 1B3 which I do not have and the picture tube, which I do have, The bulb glowed dimly, then went dark. However when installing the picture tube, the bulb glows brightly, a 25 watt bulb. Does this mean I have a shorted picture tube, or could it be a short somewhere else, if so where do I look? This is my first experience inside a TV set.

Any help is much appreciated. Thanks!


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Thu 23, 2014 7:18 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 747
Location: Littleton, CO USA
So far, so good. The set uses a series string for the filaments. Installing the CRT completed the circuit so the set will now draw more current. Go to a 100 watt bulb. The 1B3 is not part of the series string, but it is necessary for the set to show a picture.


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Thu 23, 2014 9:24 pm 
Member

Joined: Oct Thu 23, 2014 5:15 pm
Posts: 37
Thanks Philco Don. I tried it with the 100 watt bulb and the bulb lit fairly bright, but then gradually got rather dim. Is this what is supposed to happen? Hope I'm good to go!


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Fri 24, 2014 12:19 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 9623
Location: Redlands CA
That's what's supposed to happen. 100 watts probably isn't enough to run that set though, since it dims at 100 watts I'd move up to 200, or just plug it in directly and see what happens, there doesn't seem to be any shorts.


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Fri 24, 2014 2:18 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1539
Location: Manitowoc, WI USA
If there was a short, you'd have a bright bulb!

_________________
We improve things by making them worse...


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Fri 24, 2014 11:49 am 
Member

Joined: Oct Thu 23, 2014 5:15 pm
Posts: 37
So far so good! I plugged the set in this morning. No smoke, sparks or flames! All the filaments light up. That does not mean all the tubes are good though does it?


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Fri 24, 2014 5:39 pm 
Member

Joined: Aug Sun 01, 2010 1:12 am
Posts: 8426
Location: Minnesota
only that the filaments in them, are.


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Sat 25, 2014 8:18 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 3389
Location: Olympia WA USA
In the HV area, rounded "globs" of solder were normal. They had no sharp points to cause "corona" discharge or arcing. I saw this on the 1B3 sockets, sides of the HOT, and in the resistor divider chains.

As to the missing 1B3, PM me with your shipping info & I'll send you one. I have at least a hundred of them. Is it the tall one or the shorter 1B3/1G3 you need?

_________________
FrankB
WB7ELC
Member: TCA & Steel Soldiers.
" Break down the wall"


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Sat 25, 2014 12:02 pm 
Member

Joined: Oct Thu 23, 2014 5:15 pm
Posts: 37
Thanks Frank! PM sent.

I was lucky enough to get a variac for free with the set! When I get the 1B3 installed, would it be a good idea to bring the set up slowly on the variac? I've never worked on a tv before and the voltages are 10X higher than in audio amps, so it makes me a bit nervous.


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Sun 26, 2014 3:17 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 3389
Location: Olympia WA USA
Yes- bring it up slowly.
It would be a very good idea to replace all the filter caps first though.
If you decide not to do that, monitor the current VERY carefully to save a power transformer from frying.

_________________
FrankB
WB7ELC
Member: TCA & Steel Soldiers.
" Break down the wall"


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Sun 26, 2014 5:16 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5149
Location: Woodinville, WA USA
That is a series-string TV -- no power transformer to fry.

The original poster said he had finished recapping. And the TV already passed the dim-bulb smoke test. If the recapping included electrolytics, there isn't a huge risk in just turning it on.

On the other hand, since you have a variac, there's no harm in learning how it's used. Don't expect many signs of life (other than glowing filaments) until you reach at least 80 - 90 volts.

The best way to use a variac is with a meter so that you can watch for excessive current draw, which could indicate a short circuit, for instance. The Sams manual says this TV should draw about 1.05 amps at 117 volts AC.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Sun 26, 2014 1:52 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 12941
Location: Fernandina Beach, FL
philsoldradios wrote:
That is a series-string TV -- no power transformer to fry.

...

The best way to use a variac is with a meter so that you can watch for excessive current draw, which could indicate a short circuit, for instance. The Sams manual says this TV should draw about 1.05 amps at 117 volts AC.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html


And to add to what Phil has posted above, you may want to purchase a "Kill A Watt" electricity usage meter. Just as Phil has described, I used mine when I first applied power to a Motorola VT-71 that I had replaced the capacitors in. I was able to monitor the voltage and then switch to the current and when reaching 117 Volts AC, the current draw was exactly what the Sams Photofact specified. They are about $25-29 or so and even Home Depot sells them.

Just a thought.

_________________
Don


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Sun 26, 2014 8:47 pm 
Member

Joined: Oct Thu 23, 2014 5:15 pm
Posts: 37
Thanks for all the info guys! The variac I have has a voltage meter only. The only other tool I have is an Elenco LCM 1950 multimeter.. Could'nt I use the multimeter to test current draw? It does have that function, up to 10 amps. Measuring current makes me a little nervous though, as I fried a transformer on a guitar amp once, due to a clumsy move. Expensive paper weight/ door stop.

At around $25.00, the kill-a-watt might be worthwhile if it's easy to use.


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Sun 26, 2014 9:05 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5149
Location: Woodinville, WA USA
The Kill-a-watt is very simple to use. Read some online reviews to see what it's about. Then you can pick one up at Home Depot if you're in a hurry. As Don says, you can plug the Kill-a-watt into your variac and then plug your TV into the Kill-a-watt. Use the Kill-a-watt's voltage reading to set the AC voltage with the variac, then press a button to switch to the amps reading and see how much current is being drawn through it.

Phil Nelson


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Mon 27, 2014 4:07 am 
Member
User avatar

Joined: Dec Thu 06, 2007 11:54 pm
Posts: 2792
Location: Hayward, California USA
I also use a Kill-A-Watt when testing old TV sets, to watch the current as I increase the voltage. I put mine on the input to the Variac, though, in case the device itself has any problems running on low AC voltages.

_________________
Quote: (Antique TV collecting) always seemed to me to be a fringe hobby that only weirdos did.


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Mon 27, 2014 3:18 pm 
Member

Joined: Oct Thu 23, 2014 5:15 pm
Posts: 37
Sold on the kill-a-watt, I'll pick one up today.

When re-capping the set I noticed that all the large paper/ wax caps were marked with a band on one end indicating the outer foil, None of the metallised caps I used were marked. Does it really make a big difference which way they go in?
Is there any easy method to determine which lead is the outer foil? In audio amps I know it makes for a quieter amp.


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Mon 27, 2014 5:28 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 2302
Location: Seattle, WA, USA
To tell which is the outer foil, connect the capacitor directly across the input of an oscilloscope channel, then turn the sensitivity of the oscilloscope channel (v/div) to maximum (i.e .01v/div). Grip the body of the capacitor in your fingers (don't touch the leads) and note the amplitude of the resulting trace. Reverse the capacitor leads and repeat. The outside foil is connected to the lead which produces the larger trace when connected to the positive terminal of the oscilloscope.

-Matthew

_________________
If it ain't broken, you’re not trying hard enough...


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Mon 27, 2014 5:38 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5149
Location: Woodinville, WA USA
The prevailing wisdom seems to be that the foil end doesn't matter with new caps in old TV circuits. It doesn't seem to matter in the majority of radio circuits, either.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Tue 28, 2014 12:49 am 
Member
User avatar

Joined: Mar Sun 01, 2009 10:27 pm
Posts: 4206
Location: Ann Arbor, MI
Modern caps are enough smaller than the old ones that they are unlikely to pick up or radiate signals. The outside foil only matters when the cap is not a very low impedance at all frequencies of interest. If you are worried about pick up, the outside foil is connected to point in the circuit that has the lower impedance to ground.

Some modern caps do not have an outside foil.

_________________
Tom


Top
 Profile  
 
 Post subject: Re: Hallicrafters model 505
PostPosted: Oct Thu 30, 2014 12:54 am 
Member

Joined: Oct Thu 23, 2014 5:15 pm
Posts: 37
Thanks everyone. This is just what I needed to hear! I figured that if it was real important then the manufacturers would be indicating the outside foil. It can make a big difference in audio circuits for sure as far as noise.

Should get the 1B3GT tomorrow.


Top
 Profile  
 
Post New Topic Post Reply  [ 55 posts ]  Moderators: 7jp4-guy, Mr. Detrola Go to page 1, 2, 3  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: Kevin Kuehn and 11 guests



Search for:
Jump to:  


















Privacy Policy :: Powered by phpBB