Should I leave the back cover off for more circulation?

[Magnavox300]

I was putting the 1960 Magnavox back together, and was wondering
if leaving the back cover off would be better for the set?
Does it make it cooler?
I also thought maybe a small fan installed would help?
Unless all the heat in the back is normal, and this was built to tolerate it-

[Sandy G]

Interesting. Hard to say what's best. Unless you wanna run the set all the time, I'd think that leaving the back on would be better-If for no other reason, it would keep stuff outta the "Innards" that doesn't belong there. These guys WERE designed for a non-airconditioned world-And a world where EVERYONE smoked, which couldn't be good for all the gunk that accumulated on 'em back then.

[snelson903]

i thought about doing that, but i think it might drag more dust than normal threw there with the static charge allready there it might load up pretty fast . maybe if you put a fan at the top of the back facing out ,and slow it down so you only just pull the heat off might work. try it let us know, use a small computer fan i think the 5in fan pulls about 75 cfm slow it down to about hafe.

[Phil Nelson]

Originally Posted by Magnavox300

Unless all the heat in the back is normal, and this was built to tolerate it-

It's normal for a tube TV or radio to give off heat, and if it has a cover, that's how it was designed to operate. Millions of people played these sets for years without installing special ventilation fans.

If you install a fan that isn't filtered, you may just bring a lot more dust into the interior than otherwise.

Just my $0.02.

Phil Nelson

[snelson903]

hay you can use it as air cleaner just keep the shop vac handy once month. LOL

[brokenbroken]

They were designed to run hot and did for years, but with how many service calls? I cant say how many of those calls were due to heat related issues but I am an electronic tech and can say heat is the main enemy of electronics. We install computer fans in many cabinets where multiple components share a space. Of course you'll have more dust drawn in as the side effect of more air, but if there isn't a lot of smoking around I think the dust effect will be offset. I'd put a fan in there if it was mine and I were using it as a daily driver. A lot of modern electronics such as computers and receivers have fans.

[miniman82]

I don't think a fan would be required for the common B&W 50's sets, they actually don't put off too much heat. It's the older 50/60's color sets you have to worry about, they consume literally twice the power of a similarly sized B&W one. Like Bob G, I will be installing small muffin fans into the HV cage of all my color sets soon. It should help guard against flyback overheating, since those parts are unobtainable now.

[mikeh]

I agree with miniman82, I leave the b/w sets alone with the back on. On the tube color sets I also put a muffin fan on the HV cage. I don't hear it when the set runs and after 2 or 3 hours of use the flyback is cool and there is no more dripping wax. I feel that since the old color flybacks are getting hard to come by this will extend there life. It is still important to properly restore a set and get the cathode current set correctly.
Mike

[old_coot88]

Another factor to consider is whether your line voltage might be higher than in the era when a particular set was new. Wattage (and heat) don't go up linearly with voltage, since volts X amps = watts. F'rinstance, if a set drew 1 amp at 110V, wattage is 110 watts. But if voltage is 125V, amp draw will be 1.25. Ergo, 125X1.25 = 156.25 watts.

[jhalphen]

Hi to All,

I'm a big believer in cool electronics run more reliablely and frequently use add-on small fans.

I rember reading in a tech book 30 yers ago about component technology, sorry, can't remember which one (French book) that everytime a component's temperature ran 10°C higher, long term reliability was halved - statistics over thousands of hours of operation & study of failure causes.

It profoundly affected me, and to this day anything i build/modify/service follows those guidelines.

Simple everyday experience: open any item using fixed 3 pin +5, +12 VDC regulators and check their temperature. Many are shockingly hand-burning hot and run with no heatsinks nor fan. In my book, very shoddy designing indeed.

When possible, i try to re-locate these regulators to use a metal chassis heat sink with Mica/Ceramic electrical insulation.

Opening a can of worms here - just my 2 cents...

Best Regards

jhalphen
Paris/France

[miniman82]

Originally Posted by old_coot88

Another factor to consider...line voltage

That's why all my sets run on my isotap tranformer, I can dial in the exact voltage the set needs regardless of input voltage. Just turn the set on, wait for it to warm up, then read voltage going in to the set and turn the knob till it's right. 117VAC every single time. This is also important because convergence can be affected by input voltage, but the main thing is to keep horizontal output tube cathode current as low as possible to protect the flyback.

[holmesuser01]

If you have pets or kids, I'd sure put the back on that set.

[old_tv_nut]

If child/pet proofing is not an issue, cooling can help the long term life of electrolytic capacitors, but if you have already recapped with high-rated ones, they may outlive you anyway. Miniman's thoughts on flyback temp are worth considering, but I'd guess that a poorly adjusted horizontal section is going to overheat and fail no matter what kind of fan you install.

[M3-SRT8]

Yeah, heat may be an issue affecting reliability in the long term, but consider the following:

We recap our sets new with tubulars and electrolytics which are many times more superior than their 40's and 50's forebearers. They certainly can take the heat. I use 105 degree centigrade electrolytics whenever possible, and there are few values I can't get with that temp rating.

We use our vintage Tvs what, an hour or two at most per day? Certainly not 5-6 hours daily like we did when they were our primary television receiver.

[mstaton]

My Maggie color roundie combo runs all 32 tubes while using the TV. Overs 400 watts!! It's gonna get a small fan before the back goes back on even though the cathode current is only 190. Flybacks are very rare for these and I want to use it several times a week. Prolonging it's life is a must