Muntz And The Missing Damper Tube

[Tom9589]

I understand that the Muntz M-169 chassis was produced in two versions: a 16 tube version with a damper tube and a 15 tube version without a damper tube. In the damper's place, Muntz used a power resistor and a capacitor.

Two questions:

1. How well did it work?
2. If it worked OK, how come other manufacturers didn't copy the circuit?

Thanks.

[Don Lindsly]

For starters:

1. The tube and socket cost less.
2. The rectifier action produced a boost voltage that was used elsewhere in the circuits.
3. The RC combination wasted more current.

I'm sure the forum members will come up with others.

[Username1]

Originally Posted by Don Lindsly

For starters:

1. The tube and socket cost less.
2. The rectifier action produced a boost voltage that was used elsewhere in the circuits.
3. The RC combination wasted more current.

I'm sure the forum members will come up with others.

In most "how a tv works" books they explain how the damper circuit is kind
of a energy recovery scheme... Using stored energy in the yoke and timing
capacitor to provide half the sweep for each line.

So not only would the RC waste power as already stated, but the Horiz Output tube
and transformer would have to be of higher power dissipation if the damper
option was not used... Some books go into detail, and say the power
required for a no-damper setup would be more than what you would think at
just 2X... But would be 3X to 4X..... Look up horiz deflection circuits
and chose links that go to google books they are pretty good....

.

[David Roper]

There were actually two different chassis designations, M-159 and M-169. I'm pretty sure the M-159 was only sufficient for 10" sets.

[Gleb]

Originally Posted by Tom9589

In the damper's place, Muntz used a power resistor and a capacitor.

1. How well did it work?
2. If it worked OK, how come other manufacturers didn't copy the circuit

Unfortunately, RC is just a cheaper substitution of a damper diode. It could give worse horizontal linearity, especially at the left part of the screen, and less range of hor.size control. The point is the diode damper actually helps to sweep the beginning of the lines reversing the stored magnetic energy back to the deflection coils, but RC just wastes it into the heat.

[dieseljeep]

Originally Posted by Gleb

Unfortunately, RC is just a cheaper substitution of a damper diode. It could give worse horizontal linearity, especially at the left part of the screen, and less range of hor.size control. The point is the diode damper actually helps to sweep the beginning of the lines reversing the stored magnetic energy back to the deflection coils, but RC just wastes it into the heat.

I just studied the service manual for my 621TS. They use both the 5V4 damper and the large resistor shunting it. The 721TS, which is very similar but uses a 10BP4 doesn't use it. I looked an old Admiral schematic and it seems to use a similar circuit.
According to the 621 manual, the resistor has a great bearing on the left side horizontal linearity.

[dieseljeep]

Originally Posted by Tom9589

I understand that the Muntz M-169 chassis was produced in two versions: a 16 tube version with a damper tube and a 15 tube version without a damper tube. In the damper's place, Muntz used a power resistor and a capacitor.

Two questions:

1. How well did it work?
2. If it worked OK, how come other manufacturers didn't copy the circuit?

Thanks.

Some seem to think that Bendix copied the Muntz horizontal circuit. Their first 10" set, utilized the damperless horizontal sweep and the reflex type horizontal osc and output circuit.
I feel it was the other way around. Bendix seemed to have a good engineering staff.
The tired old Urban tale about Earl Muntz, using a wire cutter and clipping out random components, until the set failed.
AFAIC, you had to have a great background in circuit design. He was just a used car salesman.

[wa2ise]

Originally Posted by dieseljeep

The tired old Urban tale about Earl Muntz, using a wire cutter and clipping out random components, until the set failed.

If there is anything to that urban legend, he'd need to use well insulated wire cutters, and kept his other hand in his pocket. I wouldn't want to touch anything around a horiz output circuit with the set running...

[stromberg67]

I wouldn't really want to own a Muntz M-159, but it sure would be interesting to compare the picture on the Muntz with a picture on a better engineered set just to evaluate the linearity, etc. My dad bought a Muntz "21 INCH" in Arlington VA in 1955, an "Urban Special" with two IF amps. Didn't need much more there.
Moved to Danbury CT, and it could barely pull in the low band channels from Manhattan, let alone the high band channels. It had a stacked 3-bay conical to feed the tuner. A neighbor's RCA had no problem with either bands. Had a reasonably good pic though, for what it was. It was one of the TVs I learned repair with, and is now history LOL.
Kevin