Predicta Tandem / Penthouse scored

[bandersen]

Originally Posted by Electronic M

Hey Bob is this the first time a sam's typo messed you up?

I've had work bleeped up by sam's inaccuracies 2-3 times now...At this point if the set is different form the sam's in any way I automatically assume sam's is wrong.

I've seen minor wiring and component differences before, but this is the first time I got burned by a bad tube chart.

[dieseljeep]

Originally Posted by bandersen

I've seen minor wiring and component differences before, but this is the first time I got burned by a bad tube chart.

Wasn't there a mistake on the Sonora schematic.?

[bandersen]

As I recall, the Sams matched the Sonora perfectly and was very helpful The mistake was that someone installed the wrong picture tube in it. Perhaps because that's all they had handy.

[bandersen]

I switched back to working on this tandem the past couple days.

The power switch has been replaced with a NOS. The original was pretty gunked up inside but looks OK after a cleaning. I suspect it would work alright if I put it back in.

I also re-installed the original tuner and replaced some resistors on the IF board.



It's very handy to have two identical chassis side-by-side to compare.

For example, this set also draws about 23% less power than specified at 117 VAC (140 vs. 180 watts).


The tube filament current is dead on at 600mA. However, the B+ about 20 volts low, but the HV is fine at 14.7 kV. Cranking the line voltage up to 127 VAC got the B+ up to the specified value, but the current draw didn't go up much.

Bottom line, the set is running fine. Go figure.

Here it is without the tinted plastic cover.


Note this is not the CRT head unit that came with set. That's packed away in storage and still needs to have the cut cable replaced.
I'm kinda dreading that task but will get to it eventually

[TV'S&MORE]

Originally Posted by bandersen

I've seen minor wiring and component differences before, but this is the first time I got burned by a bad tube chart.

When working on my Hallicrafters 506 I found mistakes in sams from calling a 39 ohm resister a capacitor to the tube chart not matching my cabinet. sams is a great reference but has let me down or confused several times.

[bandersen]

I just discovered the Philco Service Pocket Guide is wrong as well.
They show the tuner tubes correctly, but the IF should have 3BZ6s not 6DE6s

[TV'S&MORE]

What a let down when the factory service information inaccurate. I probably would have been stumped for a while on that stumbling block. I usually put a lot of trust in factory literature. This is why I when ever possible try to have multiple sources of information.

[bandersen]

I finally finished off this Tandem tonight. It's been playing a couple hours with no problems

I've tried a variety of products to clean the cable and so far denatured alcohol works the best.
This is the head unit with a rebuilt 21EVP4. Eventually I'll get around to restoring the head that came with this set originally.


The rebuilt picture tube is very bright and I had a hard time taking a decent photo.


Although the cable is 25 feet long, I suspect most CRTs ended up on top of the cabinet.


Here's a shot where the geometry defects are apparent on the right side. I think careful placement of a couple small magnets could improve the situation.

[Kevin Kuehn]

Looking really good.

It might be interesting to try rotating the yoke assembly to see if the geometry follows or stays in the same location on the screen. Probably not an easy task with the housing on.

On the audio IF can - you should be able to go down through the top slug and catch the bottom one without rotating the top.

[bandersen]

Yeah, the yoke is clamped down and can be moved without removing the housing.
After playing a few hours the audio has drifted off a bit from the video so I'll be tweaking the IF again and will see about that lower slug.