Sony Trinitron KV-1331

[liammc00]

I found this TV about a year ago at a flea market for $40. I did a service on it when I got which was replacing caps that were bad or ones that are nown to leak over the board.This TV is very low hour set as the tube is very bright with good contrast and gray scale. I use the set in a dark room so I have to turn the contrast ( picture control) pretty far down or I will need sunglasses to watch this set. The TV works well for being from 1983 and 17 years older than me.

The TV is currently hooked up to a blue-ray player, Atria VCS ( 2600 ), and a Hitachi VCR. The blue ray player is old enough to have composite out and has a USB which works great at playing videos. I use that USB feature to play old music videos from the 80s-90s. This getting off topic but I have an old 80s GPX boom box with B/W TV from 86. When I picked it up for $5 I immediately thought boombox +TV = old music videos from the 80s. Once I get the boombox fixed I will show it off.

[ARC Tech-109]

Looks good to me, far better than some of this modern "HiDef" LCD junk.

[zeno]

Yup, that set looks 98% new to me. A few 'lytics here & there & every 20
yrs & I bet it will live to be 100 yrs old.

Zeno

[liammc00]

Addendum I took the back off the set to clean the the volume control and turns out my memory is very poor as a actually recapped all but a couple I didn't have on hand. The ones I left still tested good. Also I connected up my 1984 Sanyo VHS VCR to it and the old Sanyo could stand a new pinch roller as the original is about shoot.

[liammc00]

Well the TV has suffered a failure. While watching the TV it all of sudden turned off as If I had hit the power button and no signs of smoke. I later took the back off only to find that fuse F602 was burnt black. So I a component has shorted to ground. Well with schematics hopefully I can find the bad part. If anyone knows of any failure prone parts that like to short please let me now.

[Alex KL-1]

1983! I born this year...

Typical parts, experienced Sony serviceman can point something for this model, but in general, stress parts are more prone to fail: HOT, flyback, pulse capacitors (from collector of HOT to ground). Pulse caps (=tune caps) can destroy the HOT when it fails (generally open). It de-tunes the flyback, creating a giant pulse for HOT eating...

[liammc00]

I checked the H. Out with my multimeter on diod mode and this my result I got back.
With positive lead on Collector I got 2.0 on both emitor and base. If I reverse the leads I get .500 on emitor and base. If I measure emitor to base I get a dead short no matter which way I have the leads. (Was measured in circuit)

i also just took H. output out of the board and put it in one of those cheap compnet testers from china and i have included a picture of the results

Schematic can be found here
https://drive.google.com/file/d/1VPj...w?usp=drivesdk

[Alex KL-1]

Q502 indeed measure low ohm between E-B junction at circuit due to trafo coupling, and some models even out of circuit (some have internal R). But B-C junction needs to measure pristine.
Another suspicious: IC601 (+B reg/audio), C527 and/or FBT. Or symply a bad cap in the line...

[zeno]

Originally Posted by Alex KL-1

Q502 indeed measure low ohm between E-B junction at circuit due to trafo coupling, and some models even out of circuit (some have internal R). But B-C junction needs to measure pristine.
Another suspicious: IC601 (+B reg/audio), C527 and/or FBT. Or symply a bad cap in the line...

Ditto
Most HOT's have a built in resistor E-B and damper diode E-C.
When they go they dead short E-C 99% of the time.

Look behind the HOT for a small disc cap, they often crack & burn.
IIRC its a 2200 pf 2KV. ?? Common on others too.
The reg / audio amp IC also likes to get cold joints on it.

Zeno

[liammc00]

Well the cap in this set is 1.4kv at .0055mmf and it's the only one that goes up to 1000v+ range. The cap is film and case had no cracks as well the cap tested ok at least with my multimeter. I also checked all the ceramic caps in the horizontal area too and found nothing broken.
The stk I'm not sure on how to test and in the past I did resolder the stk back when I first got the set. I did find short to ground threw c520 and If I removed c520 both pads are still shorted to ground. The cap is disk cap 330p at 500v.

[Alex KL-1]

If you isolate the pin #5 of flyback, the short continues in the line?
C516 and C529 also can "shorts" the line albeit with the H yoke rdc.
C541, also.
Or, a pin of the STK (isolate them to see if one have short to gnd).

EDIT: isolate = remove solder carefully and let the pin floating

[liammc00]

(Update) I tried what you suggested Alex KL-1 and this Is the results. First I isolated pin 5 on the flyback and no change still a 0.3 short across the pads of C520. Next I checked the caps C516, C529, and C541 and they all passed with flying colors. even though it's pretty slim chanch it's the yoke but I thought couldn't hurt and as expected no change. Then I completely removed the STK module from the board and still shorted across the pads with or without C520.

[zeno]

Originally Posted by liammc00

(Update) I tried what you suggested Alex KL-1 and this Is the results. First I isolated pin 5 on the flyback and no change still a 0.3 short across the pads of C520. Next I checked the caps C516, C529, and C541 and they all passed with flying colors. even though it's pretty slim chanch it's the yoke but I thought couldn't hurt and as expected no change. Then I completely removed the STK module from the board and still shorted across the pads with or without C520.

Cap is mounted behind the HOT, not on the PCB if it has it. Its a small
brown disc cap, the new OEM is a pleasant blue color. Common also to RCA & Panny. Yokes almost never go on SS sets, I can count on two hands full in many yrs. Most on GE & Hitachi.
Zeno

[liammc00]

Originally Posted by zeno

Cap is mounted behind the HOT, not on the PCB if it has it. Its a small
brown disc cap, the new OEM is a pleasant blue color. Common also to RCA & Panny. Yokes almost never go on SS sets, I can count on two hands full in many yrs. Most on GE & Hitachi.
Zeno

I didn't see the disk cap but maybe I'm just blind so I included a picture of the main PCB board top down. I did manage to clear the short and I accomplished it by isolating pins 11 and 12 on the flyback. If I measure the between pins 11 and 12 out of circuit I get 0.1 of an ohm.

The only time I had a yoke fail was doto the rubber wedges becoming caustic and ate at insulation of the yoke windings. Orion sets from the early 90s at lest have the same problem too. I have an early 90s Orion and the wedges were wet to the touch. Luckily I got to the set in time to save the yoke by removing the wedges.

Sorry about the picture quality but as we both know the set is very limiting on image sizes. Which is great if your my grandad that still uses dial up.

[Alex KL-1]

Originally Posted by liammc00

(Update) I tried what you suggested Alex KL-1 and this Is the results. First I isolated pin 5 on the flyback and no change still a 0.3 short across the pads of C520. Next I checked the caps C516, C529, and C541 and they all passed with flying colors. even though it's pretty slim chanch it's the yoke but I thought couldn't hurt and as expected no change. Then I completely removed the STK module from the board and still shorted across the pads with or without C520.

It have some corrosion electrolysis between PCB tracks? Or someting in this line making contact