View Full Version : N-P 7" with tubes and issues


asynchronousman
11-05-2004, 07:07 PM
~7" National Panasonic AN-609D tubed "Speed-O-Vision"

Everything's there, nothing missing, CLEAN as a whistle, nice blue cabinet, Great CRT, audio okay, tubes light, screen shade present and set runs. I would guess around 1969 to 1971. A really neat portable in the vein of Froot-a-loop(?) and the portable 8-tracks they made in the 70s

Problems are thus: tubes glow red, flips, diagonal lines some times, tuning tricky.

Biggest problem: those three-so red tubes that are always on and put out decent sized heat! This may be a quick on set but I don't believe that's normal or good. It was removed from usage and won't be back until I can assure myself it's safe to use.

Any data and ideas are welcome.

Steven

Charlie
11-05-2004, 09:15 PM
You're speaking of the filaments being too bright? Need to jerk those tubes and take a voltage reading at the filaments' pin sockets. If there is one winding in the power transformer that operates the heaters of only those three tubes, that winding may have a short.

Normally, instant-on sets only keep partial power on the filaments while the set is off... just enough juice to keep them warm.

asynchronousman
11-05-2004, 10:34 PM
I just received my EICO model 221 a scant 4 daze ago...I haven't even had time to search for a manual to download much less figure all the probes!

Looks like if the chief engineer of KSRV is back, I should give him a call. I had suspicions there was something open. I am trying to learn how to fix my own stuff, and I also have a Coyne/Sams troubleshooting book I got from bgadow, but no soldering iron yet.

tv beta guy
11-06-2004, 06:48 PM
I have one of those "Speed-O-Vision" sets in a white cabinet. Except mine has the model #AN-142 (anyone have an idea what year?) and is a 12". It is an instant on set (I guess that's why they called it Speed-O-Vision). All the tubes in mine are lit when the main power switch is off, but at a reduced voltage. It doesn't produce that much heat when off, but should not be glowing red. The TV used to work when I got it over 4 years ago, but it took almost 2 minutes of warmup time to get HV and horizontal deflection. The HOT was a GE replacement. Now all I get is audio, so that tube is shot. Other than that it worked well. I need to work on that set still.

asynchronousman
11-06-2004, 07:14 PM
Mine warms up then the picture screws up and it really won't tune too easily after that (needs spraying too).

But still, a pretty neat little set!

asynchronousman
11-25-2004, 07:37 AM
I've found another Speed-O-Vision model with different HV trouble (I think he was describing arcing). Maybe the two can get together and fix mine...

tv beta guy
11-25-2004, 06:13 PM
It depends on what type of arcing. If it is external and HV, it would hiss and you'd smell ozone. My Speed-o-Vision set did the same thing. I cleaned everything HV with alcohol. The problem was at the 2nd anode button, but that cleaning fixed it. If it's internal to the CRT, then I'd say swap CRTs and see.

Here's a pic of mine without the front shield:

asynchronousman
11-25-2004, 10:33 PM
That looks suspiciously like the one I getting! It's from a barn or something.

Chad Hauris
11-26-2004, 07:56 AM
The Panasonic speed-o-vision would use a series circuit for the tube filaments. I believe there is a resistor to drop the filament voltage in the standby mode, sometimes a diode is used to chop off either the negative or positive portions of the AC waveform...this is used without a filter capacitor in the instant on circuits to achieve an effective reduction in power to the filaments in standby mode. If the instant-on diode shorts, the filaments would be on all the time at full power.

I usually remove the instant on diode or re-wire the circuit so that the power switch shuts off all power. I don't mind waiting for the set to warm up and I believe this is safer.

Usually there is a pretty good amount of filament glow and also some appreciable heat from the tubes in the standby mode.

When you say the tubes glow red do you mean the plates? Filament glow=normal, red hot plates=overloaded tube. It is normal to get a lot of heat from tube sets, especially from the power output stages. A typical tube b/w portable is 110 watts...there is probably 50 watts or less of actual power being used to do work and there is 60 watts or more of heat to heat the tube filaments.

Picture roll after warm up is likely bad capacitors in vertical circuit. If there is both vertical roll and horizontal lines that you cannot syncronize with either the horiz. or vert. hold controls then the problem is in the sync separator circuit, again possibly bad caps.

asynchronousman
11-26-2004, 01:59 PM
I mean they are neon orange-red and could mildly toast or dry out bread, they are so warm--even in "Off". Almost the same color as the big 833 that was in KSRV's ancient Gates until last year (they bought a new one). My RCA doesn't do that, nor any of my numerous tube radios/stereo consoles.

Chad Hauris
11-27-2004, 02:29 PM
Some red glow on the plate is normal for transmitter tubes like the 833, I can remember what these look like when adjusting modulator current. The filaments on these tubes also glow brighter than regular receiving tubes.

However if there is a glow on the plates of tubes in a TV set this indicates abnormally high current draw. I can't imagine though that the plates would be glowing when the set is off (in standby), only the filament should be glowing.

Can you snap some pictures of the tubes?