An old friend on his last chance repairs: Meet Troy

[leadlike]

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:



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!

[leadlike]

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.

[jdandy]

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

[leadlike]

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....

[Bill Cahill]

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

[leadlike]

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

[Bill Cahill]

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

[Eric H]

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?

[leadlike]

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.

[Bill Cahill]

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

[leadlike]

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.

[Bill Cahill]

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

[Old1625]

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.

[leadlike]

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!

[leadlike]

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.