Problem with Little Admiral - Videokarma.org TV - Video

maxm · #1 02-15-2004, 04:29 PM

Hello,

I found this little Admiral Portable at a salvation Army and had to bring it home. Sadly it is Made in Taiwan

. After a lot of cleaning, I took a look at the insides and aside from the UHF tuner and HV rectifier, it is all tube, the tubes are even all original Admiral, suprising for an "Instant Play" set.

It is Model 9P209, Chassis TL2-1A

Well as you can see in the photo, the set has a horizontal problem, displaying as many as 4 pictures at once, and looking in my TV books, I'm guessing one thing I could do is to adjust a horizontal control, but they aren't any. The set only has 6 controls (Bright, Contrast, Y Hold, H Hold, V Linerty, and Height), and find any more on the chassis or on the outside.

All tubes are good, i tried subbing the Sync, and the Horizontal Osc tubes with no affect on the picture.

Thanks for any help, I have some knowledge of mostly Tube radio and a little TV repair, I have over 10 vintage TVs, but only 3 that work, and I am going to be trying to get more working soon, hopefully with the help of the people here.

maxm · #2 02-15-2004, 04:34 PM

Let me try that Picture again....

And Here is the Set, if you are intersted...

***Eric H*** · #3 02-15-2004, 05:06 PM

Your horizontal is off frequency.
That set most likely has a coil and slug type of horiz control on the back somewhere. It probably had a plastic knob attached to a hex shaft that went into the slug.

Look around near the horiz section and see if you can locate it.
You will probably be able to adjust it back to the correct frequency if you find it.
Only use a non metal tool designed for the job though or you'll break the ferrite slug.

Eric

maxm · #4 02-15-2004, 06:27 PM

Thanks for the Help, the problem is that I can't find ANY horizontal control on the set other than the Horizontal Hold Coil on the back.

Adjusting the H. Hold does nothing to help the multiple pictures, it just acts like a H. hold control world work.

The only other coils in the set i assume are for the IF stage, since that are shielded and in the IF section.

Here is the chassis, if this helps any.

The long white shaft is the H. Hold, the other two are Vertical Lin. and height, again, there are no more controls or coils (other than IF) on the chassis.

Thanks Again,
Max

drh4683 · #5 02-15-2004, 06:45 PM

Try checking your phase detector diode. Should be a black rectangular box with 3 pins inline. Does the picture "slip" and start moving sideways?

maxm · #6 02-15-2004, 07:45 PM

I tried to test the diode, but to be honest I don't know how to test, since it has 3 pins (two diodes?), I tried to test from two end leads to center with the diode test on my DVM. I got about 1.4V in one direction and nothing when reversing the test leads, this worked for both sides of the diode. When checking resistance, i got open no matter how i configure the leads. I tried to freeze spary the diode just to see if anything happend, and nothing happened.

The Picture is like this as soon as I turn on the set and stays they way for the five minutes, which is the longest time I have had the set on.

Thanks for all the help,
Max M.

Quote:

Originally posted by drh4683
Try checking your phase detector diode. Should be a black rectangular box with 3 pins inline. Does the picture "slip" and start moving sideways?

Chad Hauris · #7 02-16-2004, 06:32 AM

Sometime people have turned the horizontal hold coil WAY too much on sets I've seen...If yours is a coil, did you try really adjusting it for a number of turns (as far as it would go in either direction).

I would not try adjusting anything else...if the horiz. hold adjustment does not make any more difference, there is probably something in the horiz. oscillator feedback loop that is not right. A schematic or photofacts will be very helpful to trace through the circuit. Also, check for cold solder joints on the circuit board due to tube heat traveling down through the pins.

maxm · #8 02-16-2004, 06:32 PM

Checked with the horizontal hold control, it si a coil, and it did not help. Looked for any cold solder joints and found two on the HOT/Damper socket, resoldered those, and still have the same problem.

I guess I will have to get a schematic or give up on the set, just to see, is anybody here in chicago intersted in this set (I would perfer not to ship it), you can have it for $8.00 (what i paid), but i will take any offer. send me a PM if you are intersted.

Thanks for all the help,
Max M.

drh4683 · #9 02-16-2004, 09:28 PM

Hi Max,

Im in downers grove. Ive got quite a few b/w sets myself. Basically only into color tv. Do you have any color sets you'd be willing to trade/sell?

Doug

Jeffhs · #10 02-17-2004, 02:58 AM

Max,

I am amazed you are getting a picture at all, with the horizontal oscillator so far off frequency. If it were any more off you would probably lose the high voltage and/or damage the flyback or horizontal output tube, or both. If your Admiral had a power transformer (tube filaments wired in parallel), such a condition could cause the horizontal output circuit to draw so much current as to destroy the power transformer, if the low-voltage supply was not fused.

However, seeing that your set is a small portable with series-wired tubes, I would say the worst that could possibly happen would be what I just described above. If you cannot bring the oscillator to the proper frequency to produce a single picture on the screen (with any amount of fiddling with the horizontal hold control), there is a problem in the oscillator and/or AFC circuits, as has been stated in several other posts before mine, so I am not saying anything here that hasn't been said before.

One other thing you can check, if you haven't done so already, is the horizontal oscillator tube itself. I realize your set has an AFC diode (phase detector), but some tough-dog off-frequency problems can be corrected by replacing the tube.

One more. If your set has a horizontal-frequency control coil on the chassis, I would try adjusting it until you get a single, stable picture (with the hold control set to the middle of its range). Since you have resoldered all connections in and around the horizontal oscillator/AFC circuits, there isn't much left except the phase detector (which you said you checked and seems to be good), the horizontal oscillator tube itself, and misadjustment of the horizontal-oscillator coil (if your set has one).

Good luck and very kind regards,

maxm · #11 02-17-2004, 10:40 AM

Hello,

Thanks for all the help,

I tried subbing the tube (8FQ7), with no effect, there is no Horizontal frequency on the chassis, I suppose that it could be the diode, since I don't really know if I am testing it right. (See previous poest)

If it was the diode, is it still possible to get a new one of these?, are they specific to the TV or generic? (One of my TV books says there are three different types of these diodes, and they all look the same), I guess it is time to get a schematic, unless anybody can tell me what type of diode it is. Is this something I Can get at RadioShack, or do I have to order It?.

Sorry for all the questions,
Max M.

Chad Hauris · #12 02-17-2004, 11:20 AM

I don't think Radioshack carries it, probably no modern distributor will carry it either, but I think that you can take 2 regular silicon rectifier diodes like the type you can get at Radio shack and they will substitute for the dual-diode. Don't reme,ber what the polarity in the circuit is but I think the cathodes are together.

wa2ise · #13 02-17-2004, 07:16 PM

Looking at your screen shot, I don't see 4 individual images in a row. What I do think it is is several images overlaping each other. So I would suspect that the horizontal output and deflection is running at a ratio of 4:3 or 3:4 or such.
making the deflection frequency = (4/3)(correct value) for example. The person's face is nearly correct. If the deflection was running at 4X, he'd look really skinny. The sync circuits would see every third or 4th horizontal deflection a properly phased horizontal pulse and think that it is running right.

The horiz hold control, seen in your picture of the chassis, is a pot. There should also be a coil in the horizontal osc circuits. It should have a ferrite slug that can be adjusted. Try, with a plastic diddle stick designed for the purpose, adjusting it. Maybe the slug fell out?

maxm · #14 02-17-2004, 07:21 PM

Quote:

Originally posted by Chad Hauris
I don't think Radioshack carries it, probably no modern distributor will carry it either, but I think that you can take 2 regular silicon rectifier diodes like the type you can get at Radio shack and they will substitute for the dual-diode. Don't reme,ber what the polarity in the circuit is but I think the cathodes are together.

Well, I tried to replace the diode with two 1N4004 Diodes, with the cathodes of both going to the center hole for the old diode. Now the picture looks just like it used to, so now I am really lost.

maxm · #15 02-17-2004, 07:26 PM

Quote:

Originally posted by wa2ise

The horiz hold control, seen in your picture of the chassis, is a pot. There should also be a coil in the horizontal osc circuits. It should have a ferrite slug that can be adjusted. Try, with a plastic diddle stick designed for the purpose, adjusting it. Maybe the slug fell out?

Hello,

The Horizontal hold is actually a coil, it looks like a pot because is is mounted along two other pots, but it goes through that piece and into a coil. The problem with this set is that there seems to be no other hozizontal contorl coil on the chassis, perhaps something that was eliminated on a small set like this to save cost??

Thanks for the help,
Max M.