Resistors for Predicta

[Kamakiri]

I should get me a copy and leave it on my bench for people that ask me if I learned how to work on TVs and radios by watching Youtube videos

[Crist Rigott]

Originally Posted by Findm-Keepm

You forgot author / preservationist-custodian......

Hey, where can I get a copy!

[Kevin Kuehn]

Hmm. Apparently cabin fever is setting in a little early this year.

[Electronic M]

IIRC that cover was someone's photoshop gag creation.

[Kevin Kuehn]

I figured that much. It's the motivation that concerns me. Must be just a pick on Phil and Bob day.

[Crist Rigott]

What! I was really looking forward to getting a copy and having Phil and Bob sign it. Just think a signed copy.....sigh.

[Findm-Keepm]

Originally Posted by Kevin Kuehn

I figured that much. It's the motivation that concerns me. Must be just a pick on Phil and Bob day.

Ancient post of mine, I just like to praise Bob's restoration efforts when I can. All in jest.

http://www.videokarma.org/showthread.php?t=249404

[dtvmcdonald]

My comment on resistor types:

First, I always try to replace carbon comp resistors with modern film ones
that are the same physical size, not smaller. Modern film ones always smaller for the same rated wattage , which means at rated power they will get hotter: not good!
And this looks more authentic, even if they are bright blue.

Second ... some modern film types in fact have spirals of resistor element.
This won't cause a problem at audio or NTSC video frequencies ....
but most certainly can and will in VHF/UHF tuners. At 41 MHz IF frequencies,
I have no experience so can't make a statement.

[Findm-Keepm]

Originally Posted by dtvmcdonald

Second ... some modern film types in fact have spirals of resistor element.
This won't cause a problem at audio or NTSC video frequencies ....
but most certainly can and will in VHF/UHF tuners. At 41 MHz IF frequencies,
I have no experience so can't make a statement.

I do have experience at 1.03 and 1.09 GHz, and at the IF Frequency of 60MHz. Film types from Dale/Vishay (RLR05/07 series) work fine if the lead length is short. Yeah, hard to find and pricey for civilian/non industrial use, but usable nevertheless.

[Polaraligned]

Same here. I always replace with a higher wattage modern film resistor.

[Tony F]

I have a question about the main "fuse" in this set. It is open and has been by-passed with (2) 4.5 ohm 10 watt in parallel (making 2.5 ohms). I have removed all the "kludges". All I can find in my area is a 5 ohm 10 watt resistor. Is this ok ?, the next step up is 6.8 ohms.
Tony

[bandersen]

Yes, that's fine. The original was 5.6 ohms. Note that a regular power resistor is not the same as the original fusistor. A fusistor is designed to blow open like a fuse if current is excessive. A regular resistor will get hotter and hotter but not open up until it's really roasting.

I suggest adding a fuse in series with it. 1 or 2 amp slo blow should do it.

[Tony F]

I am wondering how critical the small cylindrical capacitor is on the top of the tuner (labeled L2, C204) that has the 6.3 volt brown wire running through it to the heater of the 6X8 tube is. The reason I ask is while I was replacing the .22 mfd paper cap on the top of the tuner, I had noticed that someone in the past had removed the wire for the pilot lamp. It is missing totally, and only the 6.3 volt brown wire is there. There was a solder blob and what was left of the pilot lamp wire broken off down in this 5 pf cap. I was using a needle with my solder sucker and soldering iron to extract the remaining wire. I managed to crack the cap down the side. I see that the remaining half is ok inside the sheet metal of the tuner, the top half is still there (it cracked, but did not break off completely) When I put my ECG capacitance meter on it I don't get anything compared to the others on the tuner. My goal was to install a pilot lamp wire with lamp and holder. Is this cap there just to extract any remaining "junk" from the 6.3 volt line before it hits the tuner circuit ? I guess the only way I will know is when I finally fire up the set I don't get anything through the tuner. I guess the only place to get one would be out of a scrap tuner ? It is listed as #30-1268-1
Tony

[mrjukebox160]

This might be a different chassis from yours but is shows that cap as C222 and is 1000mmf

http://www.earlytelevision.org/pdf/P...Sams-466-1.pdf

[Tony F]

Hi, On the link to the Sams you posted, the capacitor I'm referring to is C204 (it is shown in the photo of the top of the tuner). It has the 2 wires running through it. In my case there was only one wire. I was trying to add the 2nd wire for the lamp when it cracked. It is a 10L43 chassis. It comes up on page 5 of the pdf document. Also, the Philco service data seems to show it better on the schematic in regards to the 6.3 volt line than the Sams does.
Thanks !
Tony