Sony KV-2643R score
 

Always wanted this one. Well I picked it up curb style tonight down the street in my neighborhood. A sign taped to the CRT says not working. Oh well. Loaded it up in the back of a Prius and drug it home.

Red gun is extremely tired. (Typical since its driven the hardest) Green almost there too. Blue is bright as day... Typical for these early 26 inch Trinitron CRTs.
Played the screen and drive game and was able to achieve a somewhat watchable picture.

I've changed a few of these Trinitron CRTs in the past. Never attempted a rejuvenation. From what I hear its usually a no go.

I'd have to tap it in to my SENCORE cr161 as it doesn't have the proper socket.

Anyone attempted a successful rejuvenation on one of these ever? I figure maybe give it a shot. Got nothing to lose. Trinitron CRTs are not happy when bumped huh..

Never had a Sony rejuve & last more than a day. What works
usually is bringing up the filament. Jump out the low value resistor
in series with the filament up on the CRT board. Slight risk it will
short but you got nothin to loose.

73 Zeno:smoke:
LFOD !

True. I'll give it a whirl. Something tells me that these trinitron CRT's don't run at a standard 6.3 V between the heater pins.

I attempted to rejuvenate a slightly smaller Trinitron from around that era, with the result being that it got even weaker.

How does it test with higher heater voltage? Maybe you can rig something up to run it like that, instead of the more destructive route.

I was thinking of measuring the H to H voltage across the pins on the CRT neck. This should hopefully give me an idea of what it normally runs at. Even though I cranked around the screen and BKG pots, there is no red BKG pot. This is of course the weak one.

Does this set have filament voltage derived from the flyback? I think that's common on Sony TVs. If that's the case, make sure to check it with a VTVM or meter which has decent response up to 15kHz - an ordinary DMM may give a falsely low reading here, since most aren't accurate above about 1kHz.

Somewhere I have a Simpson model 303. IIRC, it worked ok, but had a sticky needle that I repaired some years ago. Would the DVM meter be a bad choice because of the frequency the flyback runs off for the ripple in the DC that DVMs cannot pickup?

And would I not be mistaken that this is literally the first 26 inch Trinitron introduced in the US outside the 21 inch?

If so, it's a score to me to add next to my 30 inch KV3000R.

They run the filament off high frequency AC, not DC. A DVM usually starts to read low as frequency increases, getting grossly inaccurate by the time you get up to approx. 15kHz (flyback frequency)

Someone correct me if this era sony doesn't power the filament this way, but I'm pretty sure they do. At one point you could buy Sony specific brighteners, which were small high frequency transformers intended to boost the filament voltage off the flyback.

Here is an example https://www.ebay.com/itm/SPB2-ISO-Is...-/182417131479

Before proceeding, make sure the filament in this TV really is powered from the flyback

Sorry I meant AC. I'll take some pictures tonight, however the neck board states an R, G, B, G1 G2, I believe and H and another H. Assuming this would be a yes since there is no single pin H and a Ground for H (heater).

Only speculation here of course. I may have it backwards.

Ok so it looks like the voltages that drive the filaments are derived from the flyback. This would require me to put my Simpson to the task, if I can find it.

Here are the pics of the pinouts. I see the resistor on H1 tied to G2. It's a 220kohm. What's that about? Going to H2 looks like a sony proprietary inductor of some type. Dont see that changing voltage.

Well in a turn of events, I went ahead and cranked up the screen drive, sub brightness and sub contrast all the way up.

5 minutes in to a bright green raster, the red popped back!

Would this technically act like a rejuvenation when g2 voltages go extremely excessive?

I'm going to run this hard like this and then readjust the drives in a few hours. Maybe the ramped up g2 drives cleared this out?

So I backed down all the adjustments to where I started, and noticed the red is now being driven towards center. The screen pots for B and G are damn near at centerline to achieve a good white balance. I have the BKG at centerline as well on all three pots.

I cranked everything up to max until I had a bright green screen with retrace lines, then it went to yellowish then red popped in. I left it like this for 20 minutes and backed it down. Then let the set cool for an hour and it stayed the same.

Well see how long this lasts I guess. Picture is pretty decent now. Just a bit out of focus around the corners, and if I turn up the picture level too high, I get green or red smearing. (Weak CRT still I'm sure due to poor focus tracking on the corners and sides of the CRT which will not pull in). I suppose I can always connect my anode probe to see if I have close to 30kv.

Ok. I have been reading back on old posts.. There was a discussion between a few members about "Econoquick"..

This design is meant to leave a few volts at the heaters when the tv is off, not half, or full voltage. I have a feeling that Sony designed this device while the energy crisis of the 70's was in full swing. Sony probably knew something.. If they couldn't get away with half voltage cause of the guidelines introduced then, they could with econoquick. Something at least had to be there at all times to keep the cathodes clean. My theory is If a Trinitron CRT is put into use, it cant sit for a while dormant with no filament activity or the cathodes will become corroded.. The fact that people probably may have been worried about energy consumption, they may have unplugged the set often while not in use, possibly drastically reducing the life of the CRT. This set set for 25 years stated by the previous owner. She recalls that the picture was perfect before it was put out of service just to replace it with a projection tv. It sat in the garage since unplugged.

Her idea of perfect, and your idea of perfect may not be the same thing. That said, it's great to hear you got it going!

Yeah, I thought of that too.. But before I started, there was literally no red and barely any green. Unfortunately I didn't snap a picture before I got to work of this condition. Everything was very "smurf like" faces were literally blue. But, yes I agree, it's hard to remember details with the human mind ranging that far back.. luckfully she told me she plugged it up in the garage to see if it worked to decide whether she would sell it or give it away and that's when se noticed the raster was all blue. Hence the not working sign on it.

Actually it is the opposite....If the heater is ran for a prolonged time without beam current the cathode will develop an emission blocking layer faster. This problem was especially an issue in early tube based computers where the heater of a triode in a latch might be ran full tilt for hours with no cathode current. Any CRT can "fall asleep" (develop an emission blocking layer on the cathode) from sitting unused for several years. A good reason to run your sets periodically.

My recommendation: if you are going to use it daily and want picture fast then the ecconoquick is good, but if you are not using it regularly unplug it or switch off the power strip it is plugged in to to reduce CRT wear.

Your chassis derrived rejuvenation is fascinating... I may have to try that on one of my Trinitrons at some point.

Almost every TV I've had the pleasure of working on, which has sat a long time since last being used, had a dramatic increase in emission, and stabilization of color tracking once I let the CRT sit at 8-9V for a while. Sometimes it stays that way, sometimes it drops right back down after it has been off a while.

Absolutely agree. Most of the vintage color sets I've picked up showed weak sleepy emission. the 8v overnight trick brought most back to life into the green.

As to Electronic M, yes I always thought that any heater without cathode use causes oxidation. I just dont understand why Sony would make a big deal of econoquick if the SS circuitry was a 8 to 10 second wait from dead cold anyway.

A far leap from a non instant on full vacuum tube tv that took 30 or more seconds to produce picture, in which yes, instant on reduced CRT life and vaccum tube life as well.

A few notes on all of this.
Econoquick is just a fast warm up CRT. No STBY voltage.

Almost all SS sets WITHOUT a power transformer use a flyback (FBT) winding
for the CRT filament. Some sets ground on end & others "float" it at apx 130V.
This is to keep the F & cathode close DC wise to reduce arking & H-K shorting.

Service notes.
Always look for cold joints especially if the set has a PCB for the CRT socket.
Early RCA in line CRT sets used a spring contact socket. Many had toasting & went intermintant ( RCA, Admiral, Maggy, Sears/Warwick ). The plastic key on the CRT would melt & the contacts burn. Repair was a new socket, remove key, clean & bend F pins out slightly then put the key back on.

Sets with H-K short & grounded F.
There was a rash of Sanyo built Sears with Sylvania jugs that shorted H-K.
This coinsided with mass failures of the Z0064 HV rect, divider that kept us quite busy ! They used a grounded F configuration. Repair was to isolate the
F from ground ( cut etch & run a wire). Place a 1.5 meg resistor between
the shorting K & f. Also add IIRC a .01 cap from the K to ground. This made the set usable again but you could still see when it shorted in the pix.
$50 sure beat a new set for the customer !

Low E. Caution some risk !!!
You should use a scope for this ! Measure the P-P filament first. You want to
increase the F about 20-25%. Most sets have a low value resistor in series
with the F ( apx 2 ohm 1 W ). Jump it out & watch the scope for the change in P-P.
Early sets had an "open" FBT with the core for the pulse winding exposed.
Try adding a turn to the F winding. Use the scope to watch the P-P. Again not
a perfect solution but sure beats a new CRT !

Instant on.
One of my biggest beefs. Instant on is a killer especially on all tube TV's from
all MFG's. All of us are quick to condemn it. BUT on SS sets its a different
story IMHO. Ask anyone here what CRT holds up best from the 70's. 90%
will answer Zenith chromacolor jugs. The flat chassis & E line CC2 sets both
had instant on............

I am tired, nuf sed fer now
73 Zeno:smoke:
LFOD !

Well I found a 220k ohm resistor on the H2. There is an H1 and H2. Obviously I cant read with a DVM. Could you elaborate on this low value resistor jumping?

Essentially increasing heater voltage it sounds.

I still have a focus issue on the outside perimeter of the CRT I cannot achieve with dialing focus around. also blue and red smearing from weak R and B emission although it retains good brightness and contrast even with the smearing with my chassis derived rejuvenation. lol

I know it's most likely a weak crt, just surprised it can retain a really bright raster with quite a bit of contrast, not like the usual Trinitron weak crt.

But it does exhibit the smearing as contrast level goes up. And quite a bit out of focus around the perimeter.

Ok. I gave my homebrew crt rejuvenation by cranking up R,B,G drives, screen g2 and sub brightness and sub contrast one more go just for the heck of it to try to bump this sleepy CRT awake since I wasn't happy about the red and green smearing issue I was having since the picture level had to be at a less than adequate level to make the smearing livable. I figured what do I have to lose, after all it was free.

So for 2 hours I let it cook like this in the garage to the intro to Family Guy where I saw it the worst.. After about 20 minutes I saw some red background flickering, then it gow worse. All the sudden the red bloomed in like crazy, then faded back to normal.. The red smear became green. 5 minutes after that, the green did the same thing, then the green smear dissapeared.

So I backed everything back down to midrange after letting it cook for another 1.5 hours.

What I found is if screen G2 is all the way up, sub brightness all the way down, this eliminates 90 percent of the color smearing.

Still convinced its a weak crt.

Btw, anode HV is right at 28.9KV. Reference decal says 29KV
I also looked over the neckboard for solder cracks.

Wrong resistor. It should be just a few ohms. If not on CRT PCB trace the F
wires back to the FBT. It also may not be there at all.

The H1 and H2 wires connect directly to the flyback via pigtail connector.

Ok. Found out my HV probe is messed up possibly. what I thought was 28.9k is actually reading 15k. It's a bk precision HV-44 probe. The damn needle adjustment was cranked up and didn't realize it. Once I calibrated it back to zero, this is what I'm seeing. Doubt the tripler is actually only putting out 15k when the set requires 29kv. Is there something I'm missing?

Could be my meter. Bout to go check some vintage sets of mine to be sure.

Huh.. My probe measured a Zenith I have the back off at 24kv. Tvs rated at 25kv. Now I'm wondering what's up. Maybe this is the reason for such poor focus? But still convinced the crt is worn out. 710AB22 is just one of those duds.

Strange. Cant imagine getting a decent pix at so low HV. Maybe you are not quite hitting the metal ? Fold up the boot & be sure. NOTE most Sonys have
a coax HV lead. The outer is HV & the inner goes to the H-STAT control.
The inner makes contact to a small spring on the CRT. If you dont use the
removal tool you can loose or bend the spring. Remove the 2 HV claws
first then pull strait off. Dont use the bend & rip off method !

73 Zeno:smoke:
LFOD !

Think my probe is shot. The needle is sticking. looking for a replacement. What's the best way to adapt my sencore cr161 to read how bad this CRT actually is? Thinking of using some wires and alligator clips. What do you guys think? I know I need heater, ,R,G,B, g2 and g1 and ground right? I'm not aware of the stripe colors on the jig? Do I need to use those or just the common colors?

Its putting out a mediocre picture with sub brightness down, and screen drive turned all the way up surprisingly. just out of focus around the outer areas. Wont come in at all. Center of the raster is clear as a bell and the smearing is gone while over driving the G2.. But I can tell the tube is weak.

I know now that the filament voltage is 6.3v ang G1 is 50v. Would use a socket CR-37 but I dont have one.

Ok so heres my setup. I used an old BK 465 to run the juice to the filaments. I unplugged the AC filament feed from the socket on the mainboard, then connected it to the BK via one of the sockets, and monitored by DMM. Honestly there is little difference besides some of the color saturation gets a little better and whites stand out more and gets brighter but nothing huge. Focus still sucks wither it's set at standard 6.3v or up to 8v.

Sounds to me like you should dump this thing and focus on your CTC39 :)

That's probably what I'm going to do, however it makes a nice test jig for some crazy ideas and figuring out how to adapt a CRT tester via homemade connections and rejuvenation attempts. Figure of I was going to waste a CRT on accident, this would be a good learning curve. It was free after all. All in the name of science..lol. I'm going to use the chassis for an RGB mod possibly for a NEO GEO arcade unit.

One way to make a universal universal (as in should work on any tester and CRT) is to find a junk scope that uses the same base as a 10BP4 (and 90% of CRTs pre1960), Rob the base off the scope tube and populate clip leads onto the pins for the gun of a 10BP4. Nearly all testers had settings and socket to test a 10BP4 so if you build a socket that adapts that to clip leads that socket will adapt almost any tester to almost any CRT...It will only one gun at a time, and you'll have to label your clip leads and consult the pinout of the tube you want to test, but it sure beats having no adapter at all.

This is exactly the universal adapter I made when I decided I wanted one. I color coded my leads based on the color code for the red gun leads in a color CRT, and have a good enough handle on which of those are what element that I can hook them up to a monochrome the (which used a different color code than a color tube) if I know or can see the pinout through the glass. Most testers only need 2 H leads, a K, a G1, and a G2 to work.

Got bored today while waiting on some caps on order for my CTC-16..

With the junk CRT tester I have connected to the heater voltage on this Sony, I performed something that came to mind.. A little experiment of sorts.

I notice that when I jump the voltage up to around 8V, I get green saturation that seems to lack at 6.3v. With heaters running at normal voltage I get green smearing to the right and in kind of reddish whites.

I would jump the CRT voltage to around 12 and without hitting the tube with a rejuvenator, I would hold it there in tap the back of the neck well I bring it the heater voltage back to 6.3v. I did this roughly 10 times and when to hold it at the 12v for about 10 minutes each time. And every minute I would tap the neck with the handle of a screwdriver. (This is because every time at high heater voltage, the green would flicker in if I tapped the neck)

Every time I would bring it back down to 6.3, the picture Room go back to a murky reddish color with greeny whites with some smearing. After about the 5th or 6th time running at 12 V I had a massive amount of green saturation, Then the picture went bright green with retrace lines. At that point I brought it back down to 6.3 and the green screen with the retrace slowly faded back down. Suddenly I had the picture you see here. No more blur Or smearing at all. On a neck of the CRT by measuring a 143 V on the green where I had a 111 V before . Blue and red
measure about a 148 V.

Is this the AKB circuit balancing the guns? I didn't thing. Set of this vintage has auto kine bias.. But man, surprisingly it looks way better. I had to rebalance the drives to compensate for the sudden green gun improvement. Red seems better too from early on with the crazy chassis derived rejuvenation I did. Lol. I'm close to dumping this thing off to e waste, but thought I'd have some fun with it. Now it looks really good...

Wonder for how long. It's been on all day and still looks surprisingly good. oh well.

Can almost guarantee this set dont have AKB. It has adjustments.
Besides Sonys AKB will cause the video to blink on & off with a jug
as soft as this one especially when cold. I asked Sony why once &
they said they didnt want sets with soft CRT's cause they are like
billboards screaming "Sony pixs suck!".

73 Zeno:smoke:
LFOD !

I kinda figured. that system was not implemented till the late 80s early 90s.

Left it on all night again. Still really good! Drastic improvement from when I first got it. Looks almost as good as the CRT on my Sony KV3000R (which is perfect).

Neat technique I came up with. Possibly overheating the cathodes temporarily in bursts may have burned away some of the contamination on the cathodes. of course this is purely speculation.

Lol kids playing Donkey Kong Super Nintendo.

Maybe I did something close to what this VKer did except I used no transformer on the G1 circuit since the G1 was already activated with the TV on during my process.

http://www.videokarma.org/archive/in.../t-257458.html

It appears that the Trinitron cathodes, being paper thin, can actually be cleaned by non destructive CRT whacking with a full on rejuvenation, but merely by burning the cathodes clean with extreme heater voltage. In sessions.

Not sure how or why, but heck, it worked, and unlike Alastair's design, I was actually seeing this happen since it was on ar the time.

Btw. Never posted a pic of how it looked when I got it. This is after I turned down the B drive. It was really blue and looked nasty.

I have however, have really crappy poor outer focus. Any ideas? Possibly a poor flyback or divider block?

Btw, heres a shot of the KV3000R in the same room.

Quick question as to screen readings? Is this an inclusive test to show how much the CRT is biasing each gun? I've always thought the closer these readings are to each other, the better the CRT is. Am I correct?

It seems that the longer I run this thing, the better the picture is getting and these readings are coming closer together. in the last day I've had to back off on the green and red a bit.

I tested the screen grids on a small 14 inch Trinitron CRT computer monitor I have here at work that's built into a CNC machine. They range all from 131v to 138v. Pretty close to each other. This CRT puts out a great picture. Guess that answers that. If one is low, that's the cathode in trouble.