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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 31st Dec 2007, 2:30 pm   #21
Nickthedentist
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Default Re: SONY Trinitrons

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Well, I've put it all back together having resoldered the video output transistors on the CRT board, the earthing straps to the CRT and IF module (the IF circuit which has already been resoldered) and I still have no picture and just a pop when turning on, although the tube does seem to fire up because the tube flickers as it should do when turning the TV off and it make s the customery sound a TV does when you turn it off.
Then what? Does the red LED at the front stay on, indicating that the set's gone back into standby, or does everything go wholly dead? Any sound?

Also, look at it in the dark. There should be a dull orange glow in the neck of the tube if its heaters are running.

Nick.
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Old 31st Dec 2007, 2:46 pm   #22
ballistic
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Default Re: SONY Trinitrons

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Then what? Does the red LED at the front stay on, indicating that the set's gone back into standby, or does everything go wholly dead? Any sound?

Also, look at it in the dark. There should be a dull orange glow in the neck of the tube if its heaters are running.

Nick.
Hi Nick

No - the LED at the front does not come on, there is no picture and no sound (presumably there should be something even though I don't know if it's tuned into a channel).

Although I have the rear cover back on, I can just make out the glow at the end of the tube neck - presumably the heaters.

Does this help pinpoint anything?
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Old 31st Dec 2007, 5:42 pm   #23
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Default Re: SONY Trinitrons

Hi there
Try slowly adjusting the screen voltage - you may find you get a dull screen with lines, ususally green. Back it off slowly and you may suddenly get full working - this is a critical adjustment so you may need a few goes to get it right - and Nick is as usual right - mark the position!
If no good, then I think you'll have a regulator (or frame chip) dry joint - it is a bit of a pain to get the chassis out - but check it isn't the chassis with little access 'doors' under it that you cut open and replace. If you don't know what I'm talking about then you haven't got them!!
Good luck
Glyn
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Old 1st Jan 2008, 12:46 pm   #24
Michael Maurice
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Default Re: SONY Trinitrons

If you read the first post, it tells you that this is the AE1 chassis from the model numbers.

As Nick says, if the single red light is on its in standby, if not then the HT should be 135V, the heaters should be lit ( according to your post, they are) and you should hear a buzzing sound from the scan coils.

Turning up the A1 should bring up a raster, if you get a single line check/replace the frame chip, if you get a small raster, replaced C531 and C532.

After carrying out these checks report back to us.

I'll send you a PM with my phone number.
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Old 3rd Jan 2008, 1:33 am   #25
ballistic
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Default Re: SONY Trinitrons

Hi Mike, many thanks for sending your phone number. I may well call you on a weekend but so busy during the week due to doing overtime for my boss everyday, battling to work on my crutches because a screw came out of the metal work in my ankle on boxing day, and coming home to look after my partner who is as sick as a dog at the moment. Anyway... the update...

Yes, turned the screen voltage up and the the raster came back, a little further and the flyback lines came back, but I don't have an aerial in this room so not tested picture yet.
However, I can tell there are still issues because 9 out of 10 it comes on with a loud POP to the speakers, and the on screen display showing channel and volume etc has only worked on one attempt of turning off and on again.
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Old 12th Jan 2008, 8:06 pm   #26
Michael Maurice
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Default Re: SONY Trinitrons

Check the soldering of IC251 and IC261, they aree the likely cause of popping sound, check the soldering of the 3 output transistors on the CRT base PCB, it can be responsible for intermittent loss of one or more of the colours, including the OSD.
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Old 12th Jan 2008, 10:00 pm   #27
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Default Re: SONY Trinitrons

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The way I rework AE1's versions B & C is s follows:
Don't forget to replace R522 with a better resistor, it will often go open or intermittent, causing high +B. It is either 100k or 150k, replacing with the wrong value will cause the +B to be unadjustable.
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Old 14th Jan 2008, 7:05 pm   #28
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Default Re: SONY Trinitrons

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I think i've had this only once and I've lost count of the number of AE1 chassis that I've repaired.
For what it's worth, I did one of these (AE1C) last week, and R522 was in a terrible state to look at - it had been cooking if the board all around it was any indication... Upon removing it and examining it carfully, you could see that the outer layers of paint/enamel had fallen away, exposing the inner spiral of carbon. This resistor is a little 1/8W, but it has to dissipate around 0.18W. Amazingly, it measured 100K within 1%!

Another resistor to check is the 1K, 1W that is in the G2 supply (sorry - manual not to hand). These go open-circuit, resulting in no picture. This affects many other models too. Not sure why - flashover perhaps?

For info, this set was in a poor state - upon powering up there was EHT and scans, but no picture. Field scan wasn't right (the auto cut-off lines at the top of frame could be seen dancing all over the place). The micro didn't respond to any commands. Several electrolytics in the PSU had leaked goo all over the place, which required about 30 components to be removed and cleaned. To improve access, I removed the audio, field and small PSU heatsinks. Then, I had to resolder about 50% of the joints on the main board. I replaced almost all the larger electrolytic capacitors, and checked the ESR of the rest. Next, inspected the various sub-boards for dry-joints, which were largely ok. Of course, the RGB output transistors needed doing, and I did the tube base socket as well. On the rear PCB (which holds the scarts), I found a massive dry joint that was actually a carbonised crator - this carries the signal from the output from the EW circuit.

After doing all this, the set worked first time. Which was good, because I didn't fancy trying to apply logic - I'm sure they couldn't have made these sets any more complicated! Still, a comb filter decoder in 1991 is quite impressive! Luckily, after all this work (2 evenings - about 8 hours in total), the tube is still good, and the picture and sound is first rate.

Hope this encourages the OP, and sorry there are no quick fixes. Most components on the main board run hot and/or carry significant currents. Strip it all down, get a good light and a magnifier glass. Oh, and a sore thumb on your left hand after operating that desoldering pump
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Old 19th Jan 2008, 10:45 am   #29
ballistic
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Default Re: SONY Trinitrons

I just have more and more respect for you guys as time goes on. It's apparent a lot of the work you do is a labour of love.

Because I have no training as such, every step of the way I come up with more questions. For example I don't have any service manuals or diagrams, so I have resorted to taking digital photos of all the connections to each board as I take it off so that I never have to post on here "where does this go?"
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Old 19th Jan 2008, 11:48 am   #30
mhennessy
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Default Re: SONY Trinitrons

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For example I don't have any service manuals or diagrams, so I have resorted to taking digital photos of all the connections to each board as I take it off so that I never have to post on here "where does this go?"
There's nothing wrong with this - I do the same

It's also worth writing on the connector itself as you remove it - look for the designation on the PCB (e.g. D-12). You may find that Sony had already printed this on the connector, but perhaps only on the larger ones...
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