Busted Sony 1210 Fixed!!
 

I got this because it was $3, when I tried it at the store a few days ago it was dead except for the red pilot light, no sound no HV static.

Today I figured the antennas were worth $3 so I grabbed it.

Got it home today and it comes right on, however it seems to have a problem.

That green line is all the raster there is, it appears to have no horizontal sweep.
Also the line is solid green which makes me thing the CRT is likely to be bad, I will have to see if my B&K has a socket for this tube, meanwhile if any of you Sony Gurus have some ideas about what's wrong with it I'd appreciate hearing them.

Turned out I do have a socket for this old Trinitron.
All three guns check well into the good range, the red gets there a little sooner than the blue and green but it should make a good picture.

I guess the presence of a 3AT2 HV rectifier tube means it's only 99.8% Solid State. :yes:

The last picture is the three color dots I got when the set is shut off.

WOW!!

I think THAT is the model of the "childhood" set I've been trying to find. wood grain, handle on top, 12"....and that "pull on" volume knob I remember so fondly :-)

NOW I know what set I'm gonna keep an eye out for!

It's from 1970, that's a pretty rare set. I have the '69 model in black. When working right, they make great pictures. Good luck getting her going!

I had a KV-1201 and it looked newer than this one, I would have thought the 1210 was newer.

Did Sony's model numbers follow a pattern where the higher number is newer or no?

Sonys about that time had seperate ckts for horizontal sweep and the HV. Check for a bad Horizontal output transistor, open caps, etc. Back in the day seens like only original Sony transistors worked as replacements. good luck.

Is the '1201 the one I have now?

That '1210 is older for sure, and a nice catch. Maybe the numbers went 1200 for plastic case and 1210 for wood, then the newer series could have been 1201 for plastic and 1211 for wood.

Years ago, I bought an aftermarket set of rabbit ears that duplicated the late-70s/early-80s Sony ones for a few dollars from (I think) Farnham Radio in New York, kind of the MCM of the early 80s. I may still have it in my garage; I'd like to find another set or two now as well.

For $3??? Now,that's a nice find!:yes:

I use to have one of these back in the 90s as a kid.. It must have been the next model up or below because I recall the UHF knob was the same size as the VHF.. It worked, and I remember after a while, having no room for it anymore, so it sat out in the yard for a while before it got trashed by the mother..

Good luck: You're going to need it. First thing you have to do is check for loose connections on the horizontal drive board. I don't know if 2SC267's are still available.
Those Sony's are great sets, but when they die, they die a miserable death.

think I have some 2SC267's in my stash..

Are the 2SC267's the ones on the bottom of the HV cage?
There's another large transistor mounted on a large heat sink at the top of the frame, I was guessing that's the Vertical?

Can I test them with the Diode range on my meter?

Lots of Electrolytics in this set too, lots of possibilities for failure here.

It looks like a nightmare to work on, very packed.

I don't suppose anyone has a schematic for this already scanned? :scratch2:

I'll second the horz drive board guess, especially around pincushion transformers. Don't overlook some total E-cap fails in this section also.

I have one of those and they are truly good receivers. Too bad a good tuner means nothing today. Bought a NEW CRT from Sony back in 1982 because it was the best looking set, by far, when used as a computer monitor.

Here's the deal:

KV-1200/1210/1220 are the same years, and are base (black plastic case), mid (wood case), and top of the line (wood case with dual speakers).

KV-1201,1211 same thing

KV-1204,1214 same thing

etc etc

Charles

PS: I may have a parts set for that, if you need. No promise, as I don't remember 100% if I gave that to someone last year. Let me know if needed, and I'll look.

Thank you Charles!

I found this coupon folded and tucked into the ventilation slots.
It expired in 1985 so someone worked on this set around 1984-85.

Here's that address today, left of the Thai restaurant.

http://goo.gl/maps/ONjG

Early ad for sale on eBay describes the first 3 12" trinitron models and shows the fancy KV 1220:

http://www.ebay.com/itm/1970-SONYS-T...item4838fd03e5

Were the first year 12" models the only ones with the low location of the ch selector knobs and "sky tune"?

not affiliated,
jr

I have an original Sony manual for the KV-1201 and some others, but not for the KV-1200/1210.

I have a 1201 and a 1220u. the 1220u works very nicely. Yes the SCR on the top of the set is vertical. THe bottom two are h out and pincushion or something to that realm. Bet your H out is open

Hmm, should go there and ask for a TV repair. :P

Looks like a home now.

Try rocking the horiz centering control (dead spot?) and check any jumpers. The H out trans could be open. If shorted you'd have less to look at. My gut feeling is a mechanical fault. good luck

Alrighty then, I got a little time and decided to have another look at this little Sony.

As you recall from the beginning of this thread, this set only has a vertical line from top to bottom, this is somewhat unusual since most Flyback powered sets can't make any high voltage unless the horizontal sweep is working, this is an early Sony though so it might as well have come from the Saucer at Roswell as far me working on it's concerned, I recognize the CRT and the on/off switch but after that...

Anyhow, it was suggested that one of the two large TO style transistors under the flyback cage was probably the HO, now since I burned up my Digital Multimeter with the Diode scale on it a couple weeks ago I only have a vintage Digital Meter to use and only on Ohms.

First I disconnected one leg of the transistor closest to the edge of the flyback cage, the set didn't operate at all like that so that one must be an oscillator for the High voltage, connected it back and disconnected the other one, now the set runs exactly the same as it did so either this isn't doing anything or it's doing something that can't be seen with no raster.

I removed it and tested it with the Ohm meter, it checks about 1 ohm both ways between the case and the one leg, the other transistor is the same number and it doesn't check shorted like this so... I'm guessing this one is bad.
It's a C806A would I be right in guessing it's actually a 2SC806A?
I see Sony sells those for (gasp) $22.55 each!

NTE has an Equivalent NTE283 for $10.53 but I wonder if it would hold up?
Also is there anything else that would have made this one go bad.

I wouldn't mind the $22 if I knew it wouldn't go pop as soon as I turned it on.

I would try the NTE one first, and if it works maybe you can buy an original one later or buy 2 NTE's for the price of the Sony one so you can have an extra. You probably can get that locally. You can try Ford electronics in Buena park or Orvac's in Fullerton or Net electronics in Downey. Not exactly close to you but it's worth a shot.

Watch for dry electrolytics in the horizontal oscillator area. Also check and scope the the B+ to be sure it's is clean and free of AC and noise, and regulating at 130v (or 135 on some Sonys). If that's low or high, fix that problem first, or there will be more blown transistors. I can't remember any tips on that chassis, but 95% of the time, all trouble starts with dry electrolytics in the power supply and horizontal on 1960s-70s Sonys ;-) .

Charles

I ordered an NTE283 this morning.
Turns out the cheapest source was my local Electronic supply house, $12.60 and no shipping, however it won't be here till next week sometime maybe.

Meanwhile I'll recap the oscillator board, there's one Electrolytic on there with the plastic sleeve shrunk halfway down the can, I'm guessing that's from heat and it wasn't made that way.

Well I pulled all the electros on the Oscillator board, all three of them, they look pretty questionable with slightly swollen rubber on the bottoms and one with the plastic pulled down so the top 1/4" of the can is exposed.
I wish I had an ESR meter to confirm their badness but since it's 40 years old I'll just assume they are bad and replace them.

I also made a list of some other fairly large Electros I can see, not sure what circuits they are in without a Schematic but figure they should go too, some of them look questionable as well.

One is a large Non Polarized cap mounted in front of the Oscillator board, it's only .1Mf but it's rated at AC 450 Volts, I guess it's just a normal non polarized cap?

There is also one large can mounted in a recess on the bottom of the chassis, I'm guessing it's the main PS Filter and since it's got HV, sound and no hum I'm going to leave it alone until I get the set working, (if I get the set working).

All the rest are modern Poly Film Caps and most likely good so I'll leave them alone.

I have two TAB "Japanese Color TV service manual" volumes that cover the KV1200 and KV1201/12, since I have had a KV1210 for 30+ years I forget but I bleeve I had this problem. It sounds like you're on the right track. PM me If you want a scan emailed.

Thank you for the offer, lets wait and see what happens when I put the new Transistor in.

I replace the three electrolytics on the Osc board and fired it up with the Transistor removed to see what would happen, without the transistor in place I still get just a vertical line but it's now bright white and perfectly straight up and down, and it fills the entire height of the screen, the oscillator is clearly heard running.

I put the transistor back in just in case I had misread the Ohms readings but it still doesn't sweep, it does however reduce the brightness and make the line green and bendy so it's probably dragging the power supply down I would guess, the surprising thing is nothing smokes or pops with this shorted power transistor in place.
Hopefully I will get the replacement next week sometime.

Kind of an odd set that has the HV circuit separate from the H sweep, it's like some of the vintage sets that used an RF high voltage supply.

I have a sweep transistor in an old Panasonic 5" Pop Up set but it's rated at 50w where the one in the Sony is rated at 125w, it might last a few seconds if I packed it in Ice before I powered it up. :D

Make sure you have that brightness down so you don't burn a line into the CRT!

Eric-

Decades ago, I worked on one of the early 12-inch Sonys, probably the KV-1201 that I have the manual for. One of that set's numerous separate problems was a vertical-sweep problem, and I remember installing two replacement-type (ECG or other) output transistors. They lasted a short time (minutes to hours), then one or both blew again. I then bought the "real" Sony parts, and they were fine. One of the few or only times I had to have OEM transistors in a device to make it work.

Your set has a horizontal issue, not vertical, so with luck it will not have the same problem.

Hi Chris, well they didn't call today to tell me the part was in so maybe early next week.

If it at least works with the NTE long enough to verify the set is worth fixing then I wouldn't mind buying the OEM part if I have to.

Yes. Only the 1220 "Premium model" had Skytune.

Cool! Good to know, that's the one I have in my storage unit. I need to re-veneer the cabinet though.

Well I have made some progress with this set.

I installed the NTE Transistor but still only had a vertical line on screen, did a little poking around and discovered I had left out the two plastic insulators that go over the screws for the transistor, I discovered this when I saw one of the insulators laying inside the Flyback cage.

I thought it something was amiss when I installed it but didn't know what until I discovered the case was at ground potential.

Anyway, fixed that problem and tried it again and now the set wouldn't turn on, got CRT heaters but no sound or HV, I figured I blew something up by leaving out the insulators but it had been running right before I shut it off, it had also been running with the old transistor installed the same way, in fact I wonder if it might have been fixed after I recapped the Oscillator board but I installed the T'sistor wrong? Well, not worth swapping it to find out now.

Checked fuses, checked voltages, had 114v on both of the large Transistors and nothing was smoking but it just didn't run.

Checked the Horiz Osc Transistor and it was good, finally I was just poking my meter around checking for B+ and I heard the HV crackle on, I have no idea what I did, checked the screen and now I have a full raster and good sound, however I don't have any video and the Brightness and Picture controls do nothing, the CRT is biased full on on all three guns, there may be a picture but I can't see it with the CRT turned full on.

Still working without a schematic, any ideas what would kick all three guns full on? Brightness control has zero effect.

I have had Sony color monitors that went "all white" (and then the protection circuits shut off the set) when electrolytic capacitors were bad.

Since you work on a lot of solid-state "newer" TVs, I highly recommend that you get an ESR meter for testing electrolytics. They are worth their weight in gold. I have a Creative Electronics one; they seem to come up on Ebay fairly often and sell for under $100 there. It is actually not that complex a device, just an oscillator and a circuit to measure the signal that comes through the capacitor being tested, I think. Decades ago, my co-worker duplicated the one we had in our shop in Illinois when they could not find any new ones to buy anymore.

Tonight the set wouldn't start again, there were voltages missing in some places where I knew they should be, poked and prodded, checked Diodes and so on but nothing.
Finally I just took the soldering iron and soldered a lug on a terminal strip that I had poked previously when the set mysteriously started running, sure enough it started running again. The connection on the lug looked fine but maybe it was a cold solder joint somehow, I'll see tomorrow if it'll still run but it worked all evening while I was trying to figure out the video problem.

If I disconnect any of the RGB wires on the CRT socket board that particular color goes away so I know the CRT is responding, the Picture control grounds the Base of a small transistor and that seems to be working OK too.
I'm not sure how the brightness control works just yet.

I just found and bought a factory service manual for this thing on eBay so perhaps when I get that I may be able to figure this out.

I suspect bad caps too but without knowing which ones are in what circuit it could be difficult to figure out, I don't want to go through the expense of shotgunning them right now either, not until I see a picture on this thing.

I bought a service manual for this set, now I can actually check some voltages and know what section I'm working on.
I also took the manual to the Electronics Store and bought a bunch of electrolytics, this isn't every cap in the set but it's enough to make a start and to have on hand if I find I need a particular one.

This whole pile of Caps was only $10, because they are very small values and voltages. One is only .47@10v, the tolerance on most is -10% to +150% so that gives a lot of wiggle room on those odd values.

And this is why I hate working on Solid State gear.

I was rotating the set to get to the Horiz Hold control and the tip of my Soldering Iron came in contact with the metal chassis of the TV, pow, dead set, I wish I had had one or the other on an Isolation Transformer! :no:

I figured I blew the fuse, there are two fuses in this thing and one circuit breaker but none of them blew.
Funny thing is nothing else seems to be shorted or blown either, the set just won't run, the CRT heaters don't light either despite being on a separate transformer which is getting AC voltage as far as I can tell, however the workings of this set are a bit confusing to say the least.

I did check the CRT to see if the heaters are still ok and they are so it's a power problem.

I do get a dial light however, and when the set is plugged in but switched off I can clearly hear the Horizontal Oscillator running, it winds down though when I switch it on.

The set was having a power supply problem to start with, it didn't want to power on cold first try, tonight I had to switch it on and off about three times before it would start so maybe I just finished off a bad Filter in the PS somewhere?

I can upload the PS portion of the schematic if anyone thinks they can assist me here, I would sure appreciate it!

This thing is from another planet, or so it seems. :yes:

Yup.....Used to say that when I was 20 even, that Sony Trinitron sets were "alien"....and I have NEVER managed to bring one back.

Only RECENTLY claimed my ONE and only Sony victory....and it's an old 700U set I had sitting around for like 25 years. I had that 700U since I had JUST come from Hong Kong and wanted a real portable set since I wasn't stable yet. From a garage sale, it ran for maybe a year or two and then VERY suddenly had only a white raster. It's an old B/W set...but to this day the only Sony I have ever revived. My next one looks to be the 8-301W that I have MOSTLY running.

Eric-

I first learned (the hard way!) what a "hot chassis" is when I was installing a little kit "frequency counter calibrator" into my Sony KV-1922, in 1980. I started to hook an oscilloscope probe's ground clip to the chassis when I got the big BANG! and the TV went dead. On mine, one or more of the main diodes after the power switch had blown.

I hope you can find a good deal on an isolation transformer if you do not already have one.

Does a variac also serve as an isolation transformer? I have been trusting that I'm isolated by using a variac. My assumption being...that it's a big transformer.