An old friend on his last chance repairs: Meet Troy
 

Hello folks, you may remember Aker Veg-o-matic's tempermental olympic television, Troy. Well, veggie had him listed as free in the classifieds on this site for like six months until I couldn't stands it no more, so now I have him. He is in imaculate condition, however, it seems that he has already been to the restorers with few results. Here is a link as Troy is right now:

http://i288.photobucket.com/albums/l...e/100_1380.jpg

Okay, now Veggie tells me that the restorer replaced most of the caps, as well as the flyback and the yoke. After having pulled the chassis open, it appears that the flyback and yoke are new and clean enough looking compared to their surroundings to verify this. There are about five caps on this that haven't been replaced. One tube is missing and most of the tube shields are AWOL as well. What tubes are there are almost all replacements. CRT appears to be the original as it has the Olympic badge on it. Now, all this tv did for the restorer was to burn up a resistor when powered up. Running it up on the variac didn't burn anything, nor does anything on the chassis look burned. However, the variac soft start only produces a slight hum in the speakers (hey! it has two speakers!). I mostly fix radios, but I just had to try and save this one. I'm going to check this one out against my SAMS and see what I can see. Except for transformers and coils, I should have enough parts to get this one going. With so few caps to replace, I should be able to update soon with a progress report. Wish me luck!

gah, can't get the picture to work. Here is the physical link. Maybe someone can make it work:

http://s288.photobucket.com/albums/l...t=100_1380.jpg

copy and paste works on my computer. Hopefully yours too.

I remember that television. My dad thought I was his remote control........Boy, put that on channel 5.

hey, that wasn't too bad! I found the major problem with the restorer's work-he soldered a B+ connection to ground, hence the burning of resistors. The power resistors that burned were replaced. All other caps were checked to verify their proper connections. I replaced all of the electrolytics as some were just way off in value (100 mfd for a 47 mfd) and replaced the remaining caps.

Powering it up, I got high voltage and a raster! However, I believe that there may be problems with the yoke, flyback or both. I get a keystoned raster that fills 50% of the screen at half bright, and as bright is turned up full, the image expands, darkens, and disappears. No video or audio signal is discernable. I did not check volts yet, but all ohms are normal per the SAMS. Swapped out the horizontal, hv rectifier and damper tubes-no change in performance.

This is where I would need AK help to proceed-where should I go from here? The raster for what it is seems very bright, so I would hope this set isn't a junker just yet....

OH, oh. Sounds like a shorted yoke.
Bill Cahill

Well, crap. So much for the 'brand new yoke' I suppose. However, what would cause this blooming effect with the brightness settings? Is that inadequate high voltage from the flyback? Or is that all part of the yoke issue?


Where can I get a 90 degree yoke from? Here is a whole mess of part numbers:
Olympic part # cl-3600-4
halldorson part # DF607
merit part # mdf-92
ram part # y90f19/43
rogers part# pcm2045
stancor part# dy-16a
thordarson part# y-16
triad part# y-41 and nw3

I'll look in my new old stock yokes. I doubt I have it, but, you never know.
Most times the yoke doesn't cause blooming, but, you never know.
If it is shorted enough, it could cause low hv, which you obviously have. Or, could be somebody put the wrong part in...
Look at the yoke for brand name, and, part no.
Bill Cahill

A weak high voltage rectifier tube will cause it to bloom and fade out.
When you say it's keystoned what exactly do you mean?
Is it signifigantly taller on one side of the screen than the other or it it equally short on both sides?

Checked out the yoke-no makers marks, just stamped "y-89" on the body retaining clamp (the larger clamp, not the tiny one that affixes the yoke to the crt neck). Pins 1&7 test right on 41 ohms, as per the schematic's call for the vert half. Pins 3,5,8 all test for continuity (short) instead of the 30 ohms per the schematic. I guess shorted horizontal section would give me the keystoned horizontal sweep, and perhaps crappy bloom-worthy HV. The cap in the windings is not shorted, btw.

I think I found a replacement on a certain auction site. The numbers on the SAMS pretty much match up (SAMS says y-41):

http://cgi.ebay.com/RCA-Deflection-Y...QQcmdZViewItem

Or I could just wind my own if I can haul this thing from Hungary:

http://cgi.ebay.com/TAGA-DY-Deflecti...QQcmdZViewItem

EricH: I pulled a known working 1B3 from my RCA and put it into the Olympic with similar results. As for the keystoning; it is a flat-topped pyramid shape-equally truncated on the upper left and right sides.

Yep. Sounds like horiz. windings are shorted.
Not sure on yoke you found, but, it may work. Late sets , I have no information on. I do think this set is worth saving.......
Bill Cahill

I just tested all of the basic voltages (nothing over 1kv) and found most of them to be in line. If you want to follow along, SAMS 438 is where you want to be. This is model cb137.

Okay, now there were a couple of voltages that were off: namely the plate voltages of the 12ax7 sync seperator, 6cm7 vert multiplier, and the 6dt6 audio detector. All plate voltages were off by about 30 percent.

The most alarming reading came from pin 4 of the HO tube, 6dq6 it was less than half of the prescribed reading. Curiously, this more or less connects to nothing else but 3 components that all test normal and then the 265 volt source which tests just fine. So about 70 extra volts are being lost here (should read 140 at pin 4, reads 60 instead). Hopefully these readings will be of some help.

Your low reading on horiz. output may well be due to overloading from the shorted yoke. It's putting an un due strain on the flyback, which is loading the whole circuit down.
NEVER measure voltages on flyback, hv rect., damper, plate of horiz. output, and, plate of vert. output.
H V polse is there, and, you would zap your volt meter, plus, possibly give yourself a nasty jolt.
Bill Cahill

Yeah, what Bill sez. You need to R&R that defective yoke before agonizing over voltage readings. If you still have a low reading at pin 4 of the HOT after yoke replacement then you may be dealing with insufficient horizontal drive, which will increase the overall cathode current and excessively load the supply to G2.

Also in agreement on staying away from the HOT anode and flyback with the test prod. In fact the prod would never get there before an arc would form. There are other ways in life to get a thrill.

Well, I guess I'll give Moyer a call tomorrow and see if they have yoke. It seems like this is a pretty standard part. I'm still concerned about not hearing any audio when it is powered up, but I had my B&K television analyst out today, and I injected audio and IF all along the line and got signal so that system seems to be at least fundamentally working. Can't do much more without a picture for now. Thanks for everyone's help and interest so far.

And because we can't say it enough-stay away from those high voltages! I only measured off of pins that were deemed safe by the SAMs and making positive as to what pin I was going to touch. Ran off of an Iso transformer and sat on my free hand too. I still remember a Lionel trainset blowing me across the room as a kid, and I really don't need to feel that again!

Well, this isn't very good- Moyer doesn't seem to have any yoke to match my set. I guess I'll have to fight over the (possible) match on ebay and hope for the best. From what I discussed with Veg-0-Matic, he bought the replacement yoke for this tv from Moyer, so I guess he may have gotten one of the last, if not the last one from them.

Well the yoke arrived yesterday! As it turns out, the only difference in the part numbers is that the one I got comes with a bonus wiring harness. I fired up the tv twice: once before the yoke was installed and once after. HV did not fire up either time. Therefore, no raster, no HV high pitched sound, etc. I am just totally disgusted with this thing. All the low voltage measurements I made before are the same. Swapped tubes, no change, etc. Any ideas on where trouble may lie now?

If you still have decent voltages I think I would move to the HO tube and damper. If you haven't swapped them yet, good time to do it. Still no audio?

Veg tried very hard to talk me into that set! No room at the inn, or it would be me trying to get that thing running!

Hi,

I think ye have a bad HO tube and damper issues here. Both can load things down. Good luck and Karma. Olympic sets of the era are hard to find working. This would be a nice restoration for sure and one which is uncommon.

No sweep whistle, check the HOT to make sure its plate isn't turning red, which would indicate horizontal oscillator or drive failure. G2 voltage reading will be down also if the HOT is not getting drive. It is possible that something in the horizontal drive circuitry is not quite right, and is letting go. New capacitors can be defective.....

If the person who restored the set pulled a B+ boner such as mentioned in your first posting there may be other bizarre stuff you need to search for.

What I would do is...
1. remove the plate cap lead from the horizontal output tube. Hook the disconnected lead up with an alligator clip lead to the voltmeter and measure the voltage (since the HO tube is not in the circuit you won't generate HV AC)
You should read about the B+ voltage. With this you can see if supply voltage is getting to the HO tube. This will also check if the damper is working because the B+ has to go through the damper before it gets to the flyback.

2. check negative grid voltage at HO tube grid with the flyback connected back in the circuit. Should likely be more than -30 volts. If the neg. grid voltage is low there is likely low drive from the oscillator.

Sometimes the audio detector stage runs off the boost voltage and if the HO Circuit isn't working right this can cause no audio.

Another possiblilty is if there is low grid drive to the HO tube it got destroyed from the overload. Had this happen on an RCA CTC-16...once I fixed the oscillator circuit and replaced the HO tube it was fine. (there was a lack of plate voltage to the oscillator)

Wow! Remember this one? Well, there is news-we have a square raster! I bought still another yoke, and this time was finally rewarded with a nice, full screen! This has allowed me to find still more bonehead repairs on this thing, most shamefully the video detector diode was backwards, once that was swapped, I now get a very nice picture! Now for the current problems:

The picture STILL blooms if the brightness is adjusted at all: Turning up brightness really screws up the picture size, as well as creating as 'black hole' type of blooming in the center of the picture. Contrast adjustment is also finicky-throwing off vertical and horizontal holds.

Speaking of which, the vert and horizontal holds are really touchy-and they interact with eachother a lot. It is nearly impossible to get a stable picture for more than a few seconds. Working with the Horizontal drive and oscillator adjustments helped a little, as well as fooling with the vert lin and size.

Just wanted to give some update on this set-I haven't given up yet! If anyone has any suggestions, of course feel free to toss them out. I have one question though-the horizontal section uses two 'ladyfinger modules'-larger versions of couplates where about a dozen components are in a single unit. Are these fairly stable components? Or should they be held suspect as well? Sorry no pics, but I can't get a steady enough picture to run to the front of the set to snag one!

Any digital camera should be able to pick up a still picture.
Those couplates are known for going bad.
Blooming means hv is low, or, being over loaded.
Have you even re capped thisset yet?
New electrolytics?
Checked any resistors?
If these steps haven't even been performed yet, do so.
Leaky caps, and, bad electrolytics don't help matters any.
Bill Cahill

This set has been recapped: new electrolytics and all paper caps are replaced as well. There are quite a few original ceramic caps left in this set. I did some resistance checks and did replace any that were out of tolerance. I have several sets of nos HV tubes for this set (damper, output and rectifier) and none of these are really changing the set's performance. Right now I'm planning on redoing most of the sweep sections, but I'd hate to ditch those ladyfinger modules as there really isn't much room under the chassis for a new replacement.

I found still another wiring mistake! An entire capacitor had been clipped out of the sync separator's grid input! This basically means that entire system was not in circuit. No wonder I wasn't getting vertical or horizontal sync! I haven't hooked it all up yet, but I am getting close now-I have rebuilt the entire brightness/contrast circuits as well as the vertical section.

Gotta love finding gremlins like that. I've been lucky in that most of my sets have been mostly virginal underneath so I haven't been forced to track down bad past repairs.

Sounds like Mad Man Muntz was in there before you!

Reece