Epic Motorola score!
 

I rolled up to an estate sale today, and I almost fell out when I finally noticed the elephant that was in front of me the whole time. A 1968 Motorola Quasar Works in a Drawer! For FREE! Needless to say, I claimed it right then and there. And get this - it actually fits in my car!

Good price too!

I spent about an hour Gojo-ing it up, and now it looks halfway decent. However, the CRT is extremely tired. I let it cook at 7 volts for about 30 minutes, and it never came into the green. I'll get the B&K 470 and see if a Clean and Balance helps. It's a shame too, because it has the original Motorola Premium Grade CRT.

Priced as most sets really should be, you saved them time & money !!
Nice score, a C&B will bring it back for a time........

73 Zeno:smoke:

Oh my, that's a nice one.

am i seeing things?is that red actually instead of a dirty shade of orange?this looks like a really good moto!

Well shucks. I blew out the inside with a vacuum cleaner, and it worked. I leave, come back with some test equipment, C&B the CRT (it's perfect now) and it won't power up now. AAAAAHHHHH!!

Damn, last Friday I threw out a complete set of boards for that set:dammit:

I finally got the set fixed. Sort of. The circuit breaker was stuck, so I put some cleaner in it, and the set powered right up. I then proceed to do convergence, and that went very well. After that, I got the converter box and attempted to watch something. That's when it went downhill again. The brightness pot took a complete dump. It is stuck on the lowest setting. No matter which place you slide it, there is no picture.

Something is definitely going on with this thing. When the set is cool, it has plenty of brightness range, but as it warms up, the picture gets dimmer and dimmer until it fades out completely. At first, I thought it was the brightness pot, but now I'm not so sure. It takes about 7 minutes to completely fade to nothing. Let it sit for 20 minutes, and the brightness comes back.

My similar set is loaded full of questionable small electrolytic capacitors. I am all for finding the specific problem before changing parts, but with this set I am doing a full recap. I find the cans hold up better than the small board mount ones in 60s solid state stuff.

What is happening to the High Voltage as the set is on for a few minutes? Is it fading? At the risk of saying the obvious, you may want to change some of the capacitors, especially electrolytic ones.

Just a thought.

need to check if you got high voltage when the picture disappears or what the voltage is. These set still use a rectifier tube. check the rect tube or sub with a known good one. When the picture goes dark need to see if it is in the high voltage section or in the video section. when it goes dark need to pull the service switch see if you a service line, if not then its in high voltage and if you do its in the video section. doing a full recap right now will be just throwing parts in and not troubleshooting. get the set to stay up and running I say it would be a good idea to change caps a board at a time would be the right way to go.

Nice set, but I learned those are one of the FEW sets of that era where you really DO need to recap the boards. I can't remember the brand, but Motorola used some really crappy caps, IIRC they are brown, and those boards gave us fits in the 80's. It was not the mindset of the era to even service the boards, but to simply exchange for rebuilt. Good luck with the set tho.

Thanks everyone. I'm definitely going to check the hi voltage before and after it fades.

Do you mean the brown tubular film caps (or paper?), or the electrolytics? I'm restoring one of these too, and intend to test and replace all electrolytics, but the brown plastic ones seem suspiciously like paper capacitors. Gotta pull some and test for leakage current.

the tubular film ones. You wouldn't think they would be bad, but they have issues.
As for a recap, if you are comfortable with it, do all the boards. If yours has a specific problem, recap the board that would cause the problem, and see how it goes.
It's been MANY years since I've been in one of those, so hopefully a MOTO person will correct me on bad info, but wasn't the main board that always caused issues the JA board? (can't remember if that's the name of the board anymore)

Good to know. That look like brown versions of the old black beauty capacitors from the fifties which are often bad. This TV really was made at a time of change, all those old tube era parts mixed with silicon transistors and modularized construction. Thanks for the heads up!

I have tons of film caps, I got a couple bulk orders from China eBay sellers. I'm going to try and replace everything suspicious.

Slow fades then slow brightening of px often the
filaments loosing volts. Just see if they are changing.

HV rects were about the only thing that went on them
in the olden days, sometimes yearly. IIRC they used
a 3A3 & some times a 3CU3 or 3DB3 ?? And dont
neglect module contacts, usually can smoke them out
with light poking & tapping.

73 Zeno:smoke:

I measured HV before and after the picture faded out. 24 KV the whole time.

I think he means CRT heater voltage and any other tubes in the set (some WID sets had ~4 tubes in them).

I was just clarifying that the HV does not change. The CRT filament is also lit when the picture fades. I'm beginning to think some component is drifting and causing the bias voltage to go up as if the brightness control is turned down.

Time for a can of freeze spray....

JA board was the first switching power supply for a
TV as far as I know. Lots of fails & we didnt understand
how it worked early on. Used in the 2nd gen WID sets
but not the Quasar 2 or portable hybrids.

73 Zeno:smoke:

There are three transistors on the L module that I will be turning my attention to next. They have to do with the brightness limiter.

Motorola's used a 3AT2 or a 3BT2, HV rectifier. The old TS915's were really reliable, but they had their quirks. :scratch2:

I agree.Change the electro caps and see what happens.I remember these sets have those orange electro caps on the modules.I got to do the same thing in my two portables when I can dig them out of the dungeon.

So they were the first that came up with the PITA switching power supplies in TV's.

I am quite astonished that the CRT in my Motorola tests as good as it does. After I C&B'd it with my 470, it checks nearly brand new. It has just as strong emission at 4 volts, as it does at 6.3 volts. Don't believe me?