Hi, I am new member of this excellent forum, and this is my second post.
I just picked this nice Admiral up for $20.00.
Are these any good? I thought it was a great design, and in pretty good shape too. Only missing the antenna. Can't wait to clean it up, and recap it.
Since I am new to this hobby, (started my first TV just a few weeks ago),
I was wondering if there was any thing in particular I should be careful of, or watch out for when removing the chassis.
I just got it home today, and hooked up a RF modulator, there was clear sound, but there was also a constant loud buzz or humming. I couldn't get the picture still, and it seemed like the humming sound was possibly interfering with the picture.
Any help from the pro's would be welcomed!

Magnavox300

Prepare to do a full replacement of the capacitors, this could be the source of the hum and other troubles. C.R.T has a brightner and may need cleaning or rejuvenating.. I dont see a transformer on this tv and it will need an isolation transformer because the chassis is connected to one side of the AC line, Other than that,it looks promising.. :)

Steve..

Hi, I am new member of this excellent forum, and this is my second post.
I just picked this nice Admiral up for $20.00.
Are these any good? I thought it was a great design, and in pretty good shape too. Only missing the antenna. Can't wait to clean it up, and recap it.
Since I am new to this hobby, (started my first TV just a few weeks ago),
I was wondering if there was any thing in particular I should be careful of, or watch out for when removing the chassis.
I just got it home today, and hooked up a RF modulator, there was clear sound, but there was also a constant loud buzz or humming. I couldn't get the picture still, and it seemed like the humming sound was possibly interfering with the picture.
Any help from the pro's would be welcomed!

Magnavox300

Welcome to VK and to the wonderful world of vintage TV.

The humming sound you hear is likely 60-cycle AC hum. Your TV's picture is bending and will not stand still because the same 60-cycle hum is getting into the sweep circuits. These problems are almost always caused by defective filter capacitors in the set's main power supply. In a set as old as this one, it seems almost certain that the filters (and probably every other capacitor in the set) are weak or defective and must be replaced, as boobtubeman just mentioned. Once you do this, the picture should straighten up and the hum should disappear from the sound. There could be other reasons why your TV's picture is bending (incorrect setting of the AGC threshold control, defects in the AGC circuit itself, et al.), but I'd replace the filters and other caps first, just on general principles.

Your set is over 50 years old, so the filters must be replaced if the TV is to perform as the manufacturer intended. In fact, recapping, that is, replacement of defective capacitors, should always be the first step in restoring a vintage or antique television to past glory. Failure to do this, e. g. just plugging in the TV to the power line and turning it on without first recapping at least the power supply, may and probably will damage expensive and often NLA (no longer available) parts in the set.

Good luck. I've seen Admiral portable TVs like yours (I saw one in high school in the mid-'70s, in our basement electronics lab, when I was taking a basic electronics course), and they were good sets in their day. They can be as good as new or even better if the proper restoration procedures are followed. You will need an NTSC->ATSC converter box on your set to receive anything, as all full-power U. S. TV stations have transitioned to digital as of June 12, 2009; however, there may be some LPTV (low-power TV) or translator stations still operating in NTSC analog in your area, so you may get at least one channel with rabbit ears and without the box.

BTW, your set's picture bending could also be caused by incompatibility between your TV and your DVD player; I'd check into that if the picture still bends after replacing the filters. Modern DVDs and VCRs often do not work well with older televisions because of the set's sync circuits being unable to lock on to the RF modulator's own sync signals -- solidly or, in many cases, not at all. Older TVs were made with sync circuits designed to deal only with over-the-air TV signals, since today's advanced video technology (VCR, DVD, video on demand, et al.) did not exist when these sets were new. These sets may not operate properly with the non-standard (as the TV's sync circuits see it) sync signal from the modern RF modulator.

Thank you gentleman!
I plan on recapping everything, and can't wait to start!
Steve, any easy explanation of where the isolation transformer should go?

Jeff, I didn't know that some of these great old sets will not handle a dvd or video player very well.
I wish I could know for sure that this Admiral would before I start taking it apart!
Thanks!

Magnavox300

VCR's are the only things that can have major synch issues that I know of.

DVDs(and some other devices) can have macrovision which shows up as horizontal lines in an otherwise perfect(and synched) picture. Closed Captioning may or may not bother a set(I can't recall it being an issue with any of my sets), but is basically universal in all NTSC signals these days.

If macrovision closed captioning, etc. prove to be an issue there are boxes available to remove such from a video signal.

The isolation transformer is for the power connection for the set. Most sets without an internal power transformer have one side of the cord connected directly to the chassis which presents a shock hazard.

Welcome to VK, and enjoy your stay!

Thanks Tom,
I guess it is safe to assume that this Admiral should play movies just fine,
so I will go ahead with the project with all confidence.
After recapping and cleaning, I will take it from there.
I know some of my questions are obvious to most veterans,
thanks for everyones patience and responses.

Magnavox300

That model is a lot better than Admiral's earlier portables. Three stages of IF, keyed AGC and slightly easier to work on. Same basic circuitry as the larger screen sets, only in a smaller package.

Nice find and welcome to the forum. I believe I have the same set, but in silver. It's a P17E31 from around 1958.
I haven't had the time to restore mine yet. Here's the thread I created: http://www.videokarma.org/showthread.php?t=249661

Good luck. Bob

VCR's are the only things that can have major synch issues that I know of.

DVDs(and some other devices) can have macrovision which shows up as horizontal lines in an otherwise perfect(and synched) picture. Closed Captioning may or may not bother a set(I can't recall it being an issue with any of my sets), but is basically universal in all NTSC signals these days.

If macrovision closed captioning, etc. prove to be an issue there are boxes available to remove such from a video signal.

The isolation transformer is for the power connection for the set. Most sets without an internal power transformer have one side of the cord connected directly to the chassis which presents a shock hazard.

Welcome to VK, and enjoy your stay!
What kind of "box" gets rid of macrovision? I need one myself!

There are many different makes and models out there because people have wanted to get rid of the macrovision signal since it was introduced. I have an 80's vintage device called the Play-it-Right (can't remember the brand off hand) that I got for 5$ at a garage sale. It is about the size of a DTV converter box.

If you search Ebay (it will likely come up under copy protection remover or some such) you should find a plethora of them to choose from.

I just restored two of these, one the same colors as yours. (I have a third, but its CRT is completely dead). Both do work ok on the DTV converter boxes I have, but one has a little intercarrier buzz. The one that has buzz has a frozen 4.5MHZ if coil, so I cannot adjust it properly. I figured sound with buzz is better than no sound. (I may take this coil out of my third Admiral if I cannot get a CRT at some point). I would also recommend replacing the selenium rectifiers with solid state diodes(and a dropping resistor), although they may still work.

I replaced all of the paper and electrolytic capacitors. I also replaced the resistor in the series filiment circuit as they were both open. The trick is to get the electrolytics between the CRT and the chassis. Be carefull in placing them as there is not much room. If you place the electrolytics inside the cans of the old ones that would give you more room. Another issue is taking the set apart-be very careful as it is very easy to tear the speaker when removing the metal case. However, you can buy a speaker that works fine from RadioDaze for around $3.00, I did it. A final issue that I had is that the yoke cover had fell apart on one of them. I made another using polystyrene plastic, a compass, a hole cutter, a dremmel tool, a knife, and glue. It does not look nice, but works.

One final note is to check to make sure there are no shorts between the metal case and the chassis when you are finished. This is a hot chassis set with insulators to prevent the line voltage from reaching the case(like the Philco 17er). I also added fuses to both of my sets.

These have the switch going to the power supply instead of chassis. All you need to do is polarize the plugs (and hope your wall plugs are wired correctly).

The isolation transformer is for the power connection for the set. Most sets without an internal power transformer have one side of the cord connected directly to the chassis which presents a shock hazard.

AC/DC radios (and transformerless televisions) were made with hot chassis, one side of the line connected directly to the chassis (with some radios, such as Arvin's model 540T, in metal cabinets), for decades. The problem with a hot-chassis TV or radio is that the chassis will be "hot" with the full line voltage if the line plug is inserted into the wall socket one way, but will be "cold" (at ground potential) with the plug reversed. This assumes that the outlet you are using is wired correctly; some are not. It is always best to be absolutely sure of the polarity of the AC socket before simply assuming it was wired properly when the house was constructed. This is especially important if you decide to replace the original cord and line plug with a polarized one; if the AC wall socket is wired backwards, with the "hot" slot now ground and vice-versa, there can be real problems (such as a shock hazard or damage to the device plugged into the outlet) if the house fuse doesn't blow first -- as it should.

Radios and TVs with hot chassis in metal cabinets can be death traps if the house fuse does not blow in case of a short to ground. I once read of someone who was using an AC/DC radio in his bathroom, and accidentally contacted the hot metal cabinet while adjusting the volume or changing radio stations. The house fuse blew immediately, saving the person's life. Another, less fortunate case was that of a mother who was bathing her baby in the kitchen sink, with a plugged-in electric toaster nearby. The baby's arms got caught up in the toaster's AC cord, and the appliance promptly fell into the water. The house fuse, for whatever reason, did not blow when the toaster hit the water; however, the child was instantly killed.

i just got the same one off craigslist the same colors and everything for 20.00 mine will stay on back burnner for awile i have bigger fish to fry first

This set does have insulators built in to isolate the metal case from the chassis so that the metal case is not dangerous. However, during repairs and restoration shorts can occur, defeating this. This is the reason to check the resistance between the metal case and the hot chassis after re-assembly. Just in case, I would not recommend operating any hot chassis set(radio or TV) in a bathroom or other location where a lot of moisture is present.

Transformer-less TV sets have a few more precautions than the 1940's radios did.
A polarized plug (and interlock) was usually found on a 1950's TV, but not a plastic-case radio of the same vintage. Many of these radios have the metal knob-shafts insulated from the chassis via a capacitor and no other exposed metal parts.

No fuse or breaker will clear at the 30 milliamps that it takes to electrocute.

Ground fault circuit interrupter GFCI receptacles are always a good idea for any work bench and are code requirement for basements, garages, outdoors, kitchens, bathrooms and within 6 feet of a sink. The cost is about $12 and can save your life.

I use a neon tester to verify if the shorter slot of a receptacle is connected to hot/line side/black wire and the wider slot is neutral/white (the same as ground).

Anyone who would use an AC-DC radio in a bathroom is taking a terrible risk. I did not realize fuses and circuit breakers will not open or trip, respectively, at just 30 milliamps; it would have saved many more lives if they had been designed to open the circuit at this current level. I can understand why fuses cannot blow fast enough to prevent electrocution; however, would it be possible to make a circuit breaker sensitive enough to trip at 30 milliamps or less? Of course, a sure-fire solution would be to get people to stop using AC-DC radios in bathrooms, but some people just don't get it that they are putting their lives at risk doing this. This kind of hazard is probably outdated today as far as AC-DC radios go (most people trashed their AC-DC sets years ago when transistor sets became popular or never owned an AC-DC one), but it is still a risk with appliances. As I mentioned in another post, a baby was killed decades ago when a toaster fell into the kitchen sink where the child was being bathed by its mother, and there are probably countless other accounts of such fatal accidents as well.

This is why today's line-powered radios, televisions, and appliances are now equipped, by federal law, with polarized AC cords, and why, as DavGoodlin mentioned, the National Electrical Code now requires GFCI (ground fault circuit interrupter) equipped outlets in damp locations such as kitchen sinks, bathrooms, basements, laundry areas and the like.

BTW, the "hot chassis" design did not disappear with the advent of all-solid-state radios and televisions. I have a late-model (1999-2000) RCA 19" color TV which has a hot chassis and, of course, a polarized line cord. One major hazard with this design is if, for any reason, the speaker leads are shorted, to each other or to ground, the television will be seriously and permanently damaged.

I don't know, however, if the same thing can happen with hot-chassis tube-powered radios or televisions if the speaker(s) connections is/are shorted. Tube-powered AC-DC radios may be more forgiving of this type of short, although I would think a solid-state AC operated radio would be destroyed in an instant if the speaker(s) was/were shorted to each other or to ground. The former (speaker leads shorting to each other) seems to me to be more likely to permanently and severely damage the radio, making it instant junk. I also think that if the speaker(s) were somehow shorted directly to ground, there would of course be no sound and the house fuse or circuit breaker might open or trip, respectively; there should not be any permanent damage done to the device in which the speakers are installed and used.

The Admiral that started this thread does not have a polarized plug-I just checked mine. This set depends on the insulators. This is also true of a late 1950s, portable series string RCA that I am restoring now. It also does not have a polarized plug, depending on the insulators.

I always use and recommend an isolation transformer when working on these type of sets. The comment not about using an AC/DC radio (or the above mentioned TVs) in a wet area is correct. Our local radio club was set up at an outside festival years ago. It had just rained the day before, so the ground was wet. One our members got a shock from a 1930s Sears radio with a metal case. He could not let go until someone pulled the plug. Luckily he was not injured. In this case, as in many 1930s sets, there were no insulators!

In fact, I have several 1930s radios with exposed mounting screws, etc that are hot when the radio is plugged in. Things were pretty lax in the 1930s.

I've never seen a polarized plug on a TV from the 1950's, not sure when they started that exactly, late 60's early 70's maybe?

Anyone who would use an AC-DC radio in a bathroom is taking a terrible risk. I did not realize fuses and circuit breakers will not open or trip, respectively, at just 30 milliamps; it would have saved many more lives if they had been designed to open the circuit at this current level. I can understand why fuses cannot blow fast enough to prevent electrocution; however, would it be possible to make a circuit breaker sensitive enough to trip at 30 milliamps or less? Of course, a sure-fire solution would be to get people to stop using AC-DC radios in bathrooms, but some people just don't get it that they are putting their lives at risk doing this. This kind of hazard is probably outdated today as far as AC-DC radios go (most people trashed their AC-DC sets years ago when transistor sets became popular or never owned an AC-DC one), but it is still a risk with appliances. As I mentioned in another post, a baby was killed decades ago when a toaster fell into the kitchen sink where the child was being bathed by its mother, and there are probably countless other accounts of such fatal accidents as well.

This is why today's line-powered radios, televisions, and appliances are now equipped, by federal law, with polarized AC cords, and why, as DavGoodlin mentioned, the National Electrical Code now requires GFCI (ground fault circuit interrupter) equipped outlets in damp locations such as kitchen sinks, bathrooms, basements, laundry areas and the like.

BTW, the "hot chassis" design did not disappear with the advent of all-solid-state radios and televisions. I have a late-model (1999-2000) RCA 19" color TV which has a hot chassis and, of course, a polarized line cord. One major hazard with this design is if, for any reason, the speaker leads are shorted, to each other or to ground, the television will be seriously and permanently damaged.

I don't know, however, if the same thing can happen with hot-chassis tube-powered radios or televisions if the speaker(s) connections is/are shorted. Tube-powered AC-DC radios may be more forgiving of this type of short, although I would think a solid-state AC operated radio would be destroyed in an instant if the speaker(s) was/were shorted to each other or to ground. The former (speaker leads shorting to each other) seems to me to be more likely to permanently and severely damage the radio, making it instant junk. I also think that if the speaker(s) were somehow shorted directly to ground, there would of course be no sound and the house fuse or circuit breaker might open or trip, respectively; there should not be any permanent damage done to the device in which the speakers are installed and used.

Yes there are almost certainly such a thing as 30mili-amp breakers and there are definitely fuses at that rating, but to suggest installing them in a home electrical panel shows a clear lack of understanding of electrical fundamentals. To illustrate: Watts = Amps X Volts and a mili-Amp = .001Amps so a 100 Watt incandescent lamp being ran at 120 Volts draws 833 mili-Amps, if you look at your vacuum cleaner it probably boasts a 12 Amp motor, and the filament in the average tube draws 300mili-Amps......Thus if you installed 30 mili-amp breakers in your home electrical panel and tried to run ANY of the above appliances (or just about ANY common home appliance) off that breaker it would trip the moment any of the above are turned on. Thus making 30mili-Amp breakers useless in most applications where they could save a life.

In general it takes very little energy to kill a person....we use daily in our bodies alone enough energy to kill ourselves several times over just to breathe ,move, etc. Taking the energy we use in things like appliances and cars on a daily basis in to account the average American probably controls enough energy on a daily basis to kill the population of a large country. However most things that use energy are designed to do their best to prevent all, but motivated or unlucky individuals from actually using them in a lethal in a lethal manner.

I've never seen a polarized plug on a TV from the 1950's, not sure when they started that exactly, late 60's early 70's maybe?

My 71' Zenith is non polarized, but my 77' is so I'd say mid 70's is when polarization became standard.

I have a ~68 Portacolor with original polarized plug, the oldest example of their use I've seen on any appliance by a margin of nearly a decade.

I have a ~68 Portacolor with original polarized plug, the oldest example of their use I've seen on any appliance by a margin of nearly a decade.

Starting with the 1961 model year, all the hot chassis Motorola sets had polarized plugs and interlocks. Many others did as well. I think it made it easier to get U/L approval.

I incorrectly stated in the previous post that most series 1950's sets had polarized interlocks/plugs. :boring: DUH-me on that. Neither of my 1956 metal-case 14" BW sets have them and neither does my 1958 Philco seventeener. My 1963 Westinghouse attache 19 BW TV did have a polarized plug. Being an electrical switchgear manufacturer, Westinghouse took safety a bit further than others. This was probably optional for a long time before UL required it. Must do some research on that:scratch2:.

I got zapped quite a bit by 120 in the old days and fortunately I recoil as opposed to clenching. A Sunbeam mixer shocked me and trip the GFCI simultaneously one time. I put a grounded cord on it after that.

GFCI receptacles are OSHA required at construction sites due in part to the fact some tradesmen use older, metal case power tools where the ground pins were routinely cut off. I see guys working around puddles on concrete before a roof is on.:nono:

GFCI is simply a current transformer surrounding both line and neutral conductors. It does not include the ground conductor, nor does it require one to operate. If ANY current is going out on the line and not returning on the neutral, the differential current (usually only 6.8 mA) is detected and trips the unit open. There have been improvements over the last 30 years so they don't false-trip so much, such as from a static arc, etc.