Predicta restoration tips: Fusible resistors

Рет қаралды 1,818

Жыл бұрын

What are they? Why are they used? What can you replace them with?
5.6 ohm 5W fusible mou.sr/3DHecaZ
4.7 ohm 5W fusible mou.sr/3HvGW7D
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Пікірлер: 17

@randyvance9048 Жыл бұрын

We all learning. Your videos will help future students to be able to get the destination they will desire. Thank you.

@SeekingTheLoveThatGodMeans7648 Жыл бұрын

Old service dogs like us are not becoming more common.

@ntsecrets Жыл бұрын

I like the use of the film burn transition very appropriate

@hestheMaster Жыл бұрын

Good explanation for use of fusible resistors back in the day. Now we have thermistors available but it doesn't actually work 1:1 to replace a fusible resistor. You would have to add a fuse. Fusible resistors are still made for power supplies and chargers for electronics but in very much smaller package because of the lower Wattage in their electrical design.

@oldradiotvsc9836 Жыл бұрын

Excellent ideas! I have used a 7.5 ohm power resistor in series with a fuse holder to replace one in this "box shaped" Philco TV last year that was similar in design as a Predicta Holiday with the series string tubes, and used a 1A fuse, and it worked well.

@ScottHenion Жыл бұрын

The voltage doubler input current would be at least twice the output current, probably more due to losses in the caps.

@stuartirwin3779 Жыл бұрын

The input rms current will be many times the DC output current, because the current is in a series of narrow pulses. More like 5 times, by my estimation.

@BretFrohwein Жыл бұрын

When I was looking for a fusible resistor for my princess. I'd come across a posting with workman fusible resistor cross reference. it showed the philco part 33-1366-3 as a 5.6 ohm 5 watt fusible resistor.shortly after that, I came across someone on our FB group that was selling the philco factory replacements and I bought a couple.

@bandersentv Жыл бұрын

Interesting as the 17" Predictas draw just under 1A in the B+ circuit. 5W would right at the limit. Maybe that's the way they are supposed to work? A little over 1A and they go open? If I had some to spare, I'd experiment to see where they open up.

@SeekingTheLoveThatGodMeans7648 Жыл бұрын

I'd think, in a pinch, to put a slow blow fuse (or if possible to appropriately mount, a circuit breaker) of about 1.5 to 2 times the operating amperage, a fuse being placed in a fuse holder to make it easy to replace, in series with an ordinary power resistor of the appropriate value, and attach a note to the chassis about what I did. I would not use just a fuse, though, because the resistance is also part of the power filter's provision for elimination of hum, resisting the abruptness of rise of output voltage at the crest of each cycle of the sine wave at the "top up" of the filter capacitor. Beyond this, a great overview.

@bandersentv Жыл бұрын

I don't think that small amount of resistance has any effect on hum. Right after that fusible resistor are big caps and rectifiers plus a filter choke. That's where all the action happens.