(On Topic) Work of Art

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Love those Trinitron monitors. Great design throughout.

Tim

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Seven Transistor Labs 
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Tim Williams
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I had one fail similarly about 5 yrs back. I wonder if it had the same problem.

Reply to
DTJ

Nice writeup BTW.

Reply to
DTJ

Enjoyable read! I originally saw my first Trinitron in, I think 1973. My first job out of High School was with a video sales and service company. That was when we had 1/2 inch reel to reel video recorder/players! Sony AV3600 and the AV3650 that would edit! We sold Trinitrons with the recorders. At some point I installed a modification to provide video and audio inputs to the Trinitrons. When the Umatic 3/4" cassette machines came out those was our machines to sell. Regarding the channel 3/4 modulators, I recall, one of the Sony seminar trainers, saying "Don't reduce the value of R17 in the modulator, it will increase the power output". Hint, hint. I always enjoyed the training seminars, I always left thinking how magical this stuff is. Mikek

Reply to
amdx

In case you ever get the problem with the black level getting too bright and the retrace lines showing, here is how I fixed my similar monitor:

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here is the circuit before modification:

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Possibly there is some software way to fix it but the pot worked for me.

Chris

Reply to
Chris Jones

Horrible, heavy, hot beasts with fuzzy pixels. Recycle it and get a nice big LCD or two.

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John Larkin         Highland Technology, Inc 

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John Larkin

Nice tear down. However, I see a problem: The electrolytic in the middle of the photo, and the blurred one near the bottom of the photo, are about to blow their tops. I suggest you replace them, and check the others with an ESR meter.

Back before about 2000, I did some monitor repair along with the usual computer stuff. Sony monitors were a unique problem because of their design philosophy. Everything seemed to be sized for a specific lifetime. My guess(tm) was about 10 years life before everything failed at one time. The most obvious indication of this was the multitude of different electrolytic capacitor voltages used. If the current and temperature of these caps are known, their lifetime can be predicted.

When I dragged a Sony monitor in, and removed a dozen shields to gain access, I often found that if one capacitor was bad, they all were bad. That makes some sense since they were all calculated for approximately the same lifetime. I would walk the ESR meter through the monitor, and often find half the caps with high or marginal ESR. Replacing 50 electrolytics was not my idea of fun, but I did it a few times.

Near the end of the Trinitron era, Sony was supplying only the tubes to OEM manufacturers, who would supply their own electronics and packaging. Oddly, the overall quality improved.

Not all Sony CRT's had this problem. I had several 19" flat screen Sony monitors (model number forgotten) that lasted about 15 years and were still working when I recycled them.

The brown goo that you found was originally yellow goo, also known as acrylic cement. It eventually becomes conductive and possibly hygroscopic. That causes problems with high impedance circuits. Removing it is also a PITA. Naphtha seems to soften it slightly, but can also wreck the underlying parts. There was a discussion on the topic of "brown goo" in sci.electronics.repair a few years ago. Unfortunately, all my links to suppliers have gone dead:

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Jeff Liebermann     jeffl@cruzio.com 
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Jeff Liebermann

I found some additional suppliers of yellow goo using the description: "One component solvent resistant flame-retardant waterproof yellow fixing adhesive glue for electronic components": Duz anyone have any info on the composition of the yellow goo?

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Jeff Liebermann     jeffl@cruzio.com 
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Jeff Liebermann

I had one... heavy sucker! ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

That sounds cheap. I bet those sets were so cheap you guys didn't even put the price in the catalog! ;-)

For sure, the amount of junk in there is a lot more than just "beam goes left, beam goes right".

Tim

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Reply to
Tim Williams

There is, actually: you can find an archive of WinDAS (Sony's Digital Alignment System) on the web. There's a four pin header in the back with "TTL" serial (appears to be 5V CMOS directly off the MCU), so a level shifter and serial dongle is all you need. You can save the entire EEPROM contents and tweak the G2 setting.

It's also an ugly, awkward program (it may've been written by an intern) and can very easily be used to reset every register to nonsense values... (Good thing they are all limited, so there's no 0xf00f, even in service mode.)

Tim

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Reply to
Tim Williams

Those caps are weird, the vent pattern is actually curved, not the surface. You can maybe see this better in the overall view, where the lines look curved more than the surface.

The last one I played with had aging coupling capacitors (RGB levels way off) and the video amp solder joints were all but broken off -- whoever designed that particular model (it was a Mitsubishi Diamond something) had the genius idea of making the video board a huge, poorly supported piece, with the amp chip screwed to a heatsink on a separate piece of metal!

Replacing the little caps (1-10uF 50V thingers) and soldering all the joints brought it right back. There was still some saturation / ghosting going on at high intensity, but that was tolerable.

Ya know, I found it odd that they used a mixture of caps throughout the circuit: the standby supply has a 47uF 25V on one side, and 47uF 50V on the other. Doing basically the same thing, 12V or so I'm guessing. They did use Nichicon, Chemicon or Rubycon throughout, but yes, aging is still aging when it comes to capacitors. The +200V supply has a 105C cap, the PFC has an 85C (330uF 450V) one -- potentially the shortest life part, I might think, because of its surface area ratio.

I must have one of the lucky ones then. ;-)

Hmm, that doesn't sound like it. The one (still good) inductor has rubbery and brown stuff (I didn't test it for solvent resistance), the other stuff is gooey and brown and flowing (slowly) and readily soluble in acetone.

Tim

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Tim Williams

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

31kg curb weight. ;-) Most of which, I'm guessing, is lead in the CRT glass. The shroud actually says < 0.5uSv/hr x-ray output, which I believe comes out to approximately background radiation.

Tim

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Reply to
Tim Williams

Cool writeup, thanks! Although I agree with JohnL that you must have too m uch time on your hands if you're using these relics for any reason other th an sheer amusement.

I imagine you had a hairline crack in the solder joint. There was probably nothing wrong with the resistor. I've posted my (least) favorite example before, I think -- A12A3 from an HP 8663A signal generator:

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The thing that looks like a piece of wire is a hair. Not the proverbial RC H but close enough. It is massive compared to the actual fault, visible ju st below it where the transistor lead contacts the pad. You can just barel y see it with the naked eye when you know where to look, but you'd never lo cate it in the first place without a microscope.

I had to inspect every joint on the board to find it. I couldn't pin down the fault even with an R134A-soaked Q-tip (my version of your wooden skewer .) That was a bad day at the workbench.

-- john, KE5FX

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John Miles, KE5FX

On Sun, 5 Oct 2014 19:22:53 -0700 (PDT), "John Miles, KE5FX" Gave us:

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That is no "work of art"

I see a fracture in the solder joint, and there is a hair laying across the board. Likely an eyebrow hair, from the perfect roundness of it.

Reply to
DecadentLinuxUserNumeroUno

Here's another solder hairline crack from hell: It's the power amplifier module from a Kenwood something ham radio. I'm too lazy to lookup the details. The messy soldering job was the best I could do to bridge the cracks. This happened before I bought my fancy binocular microscope, so I couldn't see the crack(s). I walked an ohmmeter down the trace until I found TWO cracks in the trace. About 3 months later, it again developed a crack, this time between the two previous solder patches.

If possible, I backlight the PCB with a flashlight, which often makes the crack(s) visible. Of course, that doesn't work on 4 layer and up PCB's. Otherwise, I try to determine the section that's not working, and reflow every solder connection in the section with my soldering iron.

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Jeff Liebermann     jeffl@cruzio.com 
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Jeff Liebermann

Years ago I used trinitrons to test the limits of some ideas I had in my sp are time, since they could be got for not much and sold for a fair price af terwards. I managed to get some very dead tubes working again. I ended up w ith a couple that weren't really practical to fix, and decided one mad day to try something a bit out there. So I replaced an entire faulty PSU pcb wi th little more than a lightbulb - and it worked.

NT

Reply to
meow2222

Cool writeup, thanks! Although I agree with JohnL that you must have too much time on your hands if you're using these relics for any reason other than sheer amusement.

I imagine you had a hairline crack in the solder joint. There was probably nothing wrong with the resistor. I've posted my (least) favorite example before, I think -- A12A3 from an HP 8663A signal generator:

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The thing that looks like a piece of wire is a hair. Not the proverbial RCH but close enough. It is massive compared to the actual fault, visible just below it where the transistor lead contacts the pad. You can just barely see it with the naked eye when you know where to look, but you'd never locate it in the first place without a microscope.

Yikes, good thing you had the "eyes" to see it!...eventually.

All the joints in this monitor have that silky semigloss finish, gray not quite shiny, and plenty of solder (definitely a wave process). I've heard chip components can crack if there's too much solder -- or maybe the solder can do the cracking too.

Tim

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Reply to
Tim Williams

I did that years ago. Now I can view a schematic and layout simultaneously which is nice. But I still miss the sharpness and contrast of the Trinitron. It's stashed in a closet here in case the new

27" monitor fails in the middle of the workday.

Tim, very nice write-up.

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Reply to
Joerg

Buy a spare LCD monitor. They're far cheaper than a hernia operation. ;-)

Reply to
krw

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