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1971 Sony Trinitron KV 1201
I picked this up tonight, it worked when initially plugged in. After the ride home, I suddenly have no picture, not even static. The sound is still fine, though the crt isn't lit up. When I shut it off I get a momentary red, green and blue bar flash horizontally across the screen, then a green dot in the center for a minute.
What should I look for when I open this up tomorrow? Last edited by Airedale; 12-21-2020 at 02:40 AM. |
#2
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The plug will stay attached to the back, it is a safety interlock. Just pull the whole back off.
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Thanks
The case was just stuck with grime. I'll clean up the chassis and start an inspection tomorrow. Though I still need to find a schematic for this. Last edited by Airedale; 12-22-2020 at 01:04 AM. |
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For a manual go by the chassis number ( SCC-### ). In the
early Sony days the same model number can have a totally different chassis in it. Sears & Magnavox did it too. 73 Zeno LFOD ! |
Audiokarma |
#6
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What's going on here?
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#7
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Thats the main filter can on the small PS board. Looks like candle
wax to me. Not an uncommon thing to find. 73 Zeno LFOD ! |
#8
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The first thing these Sony sets needed is a cleaning of all pots and any switches.
The original operation should return but until that's done, nothing will seem right. Capacitors are usually OK or totally shot, look for bulges and excreta. Good luck.
__________________
"When resistors increase in value, they're worthless" -Dave G |
#9
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Quote:
We had a Sony come in from another shop with all sorts of vertical issues. Working through it, I found almost every capacitor bad. The shop owner said it wasn't possible a bad electrolytic was the problem because he jumped every cap in the vertical one by one (insert loud gasp that he didn't blow this Sony up by hot jumping the caps...). Every cap that was changed either improved or changed the vertical scan until the last one or two fixed it. None of those caps had any outward signs of problems. John |
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Well I can't find anything denoting a chassis number, inside or out.
The wax that is on top of the electrolytic can seems to have dripped off of the circuit board that is above it. I've given a visual inspection of the other caps, no leaking or swollen ones to be found. Rather than testing each cap I'll just take notes of their values and do a total recapping, I could use the soldering experience. I've never owned a Trinitron, let alone a vintage one. I saw this set working before I brought it home, the picture was a bit blurry. Though when I got home.. the screen didn't come on, not even static, just sound. Last edited by Airedale; 12-22-2020 at 08:59 PM. |
Audiokarma |
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Look for a blown pigtail fuse. Check electrolytic caps I power supply for short or high ESR.
__________________
Sony Trinitron is my favorite brand. My wish list: Sony KV-7010U Sony KV-1220U |
#12
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Looks like the chassis tag is on the metal above the HV
area. Before you spend money on caps get the pix back ! Be sure the CRT sockets on all the way 1st. If you do a recap only do the electrolytics. Do them a few at a time then recheck the set as you go. 73 Zeno LFOD ! |
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those are nice sets, I have one as a daily watcher. sounds like the CRT is being biased off, turning the set off releases the bias as the residual HV pulls the electrons thru.
check HV anode voltage 19kv check the voltages at the 3 cathodes of the CRT IIRC should be around 100v-110v. These are driving by the collectors of the 3 video out transistors. The grids all get voltages from boost voltage, so if you lost that, then you will have cut off the tube. boost is about 500v check pin 5 (common screen grid) on the crt should be upper 400's the common control grid also from the boost is upper 90's (pin 7) My guess is you lost the boost. Last edited by DaveWM; 12-31-2020 at 08:09 AM. |
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Thanks for the help. I'll pick up a HV probe and look into acquiring a manual.
This is a cute set, I'd love to add it to my living room for occasional watching. |
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I have the same set with " wood" cabinet , KV1212 ( the one in my avatar pic ). It works like a champ but has pincushion issues ( any ideas? -- thanks !) This set was the one in the Sony print advertisement where it was set up in a bank branch and left running for a year and a half with no servicing needed
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Audiokarma |
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