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Thread: The PVM-2730QM thread (H-STAT issue, colour bleed, convergence and more!)

  1. #191

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    Any ideas about what might go wrong on the D2 convergence board for these, @soyl? I find the adjustments don't seem to go quite far enough to perfect the dynamic convergence...
    Last edited by buttersoft; 1 Week Ago at 11:26 AM.

  2. #192

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    I don't have this monitor. I do have a 27" of the same time (KV-DX27TA) that has the dynamic convergence adjustments (H tilt, Y cross, Y bow etc.). When I take it out of the garage where it currently is I'll have to check how well they work but even the manual says that if the dynamic convergence is not sufficiently adjusted after the steps, repeat the steps as if they were aware that they don't work that great.

  3. #193

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    lol. And no rush at all. I need help to move these sets by myself, so if you get to this sometime down the track i'd still be keen to hear your findings

    I've been able to get things close enough on these sets without doing more than changing the angle of the yoke and using the pots on the D2 board, but maybe it's time to jump in and set one up from scratch.

  4. #194

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    Quote Originally Posted by soyl View Post
    The diodes work as switches for the top and bottom pincushion corrections. They are MC931. Each one has two diodes in series. If you desolder them the test will be more reliable and you can also swap them and see if the issue goes to the bottom. They're very easy to test so I wouldn't blindly replace them and I wouldn't replace any electrolytic cap before getting the issue sorted.
    Want to emphasise Soyl's comments there about not charging in and changing electrolytics willy-nilly.

    Easiest thing is to test them with an ESR meter in-circuit (no need to de-solder). An ESR meter will catch about 99.9% of dodgy electro caps this way. If you don't have an ESR meter, then you can test capacitance with better multimeters (and even some cheap ones) BUT you'll need to remove the capacitors from the circuit to test them.

    For example, when I was fixing my Sony 2730 earlier, there were 8 electro caps on the neckboard (C). I tested them all in-circuit with my ESR meter (Dick Smith/Bob Parker design, K7214) and found 2 seemed dodgy. Pulled them out and confirmed their dodginess with a multimeter (one was very dried-out, but this only visible after removal from board).

    The obvious advantage of doing things like this is that I only had to change 2 electro caps instead of 8. The other caps are still perfectly good. In retail-speak, this means I "saved" about 6 caps (75% discount!), and that is from just 1 neckboard. Imagine how many caps I could "save" from re-capping the rest of the monitor in the same way. Speaking of which, I might just go and do that soon. As you can tell, I am very fond of my ESR meter.

    As you probably know, Dick Smith is not the same company it once was. They certainly don't make ESR meter kits anymore (probably 20 years since they did). By an amazing coincidence, I just happen to have a few of the kits (K7214, ESR MkII meter) still in original plastic-wrap) in my shed, probably the last ones anywhere (let me know if you want one at a reasonable price).

    Otherwise, the same Bob Parker design ESR meter is also available as the Anatek Blue ESR meter,
    https://www.flippers.com/BlueEsr.html You can also find it on ebay (but beware of cheap Chinese fakery, look for the real thing). There are other meters that can do the same thing, but they will cost a lot more.

  5. #195

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    Quote Originally Posted by Zebidee View Post
    Want to emphasise Soyl's comments there about not charging in and changing electrolytics willy-nilly.
    Certainly, not a great method usually, in this case as I don't have a way to test in circuit and they only cost $2 each, replacing would take an equal amount of work. But I'll plan on swapping these to test first as recommended above.

    Quote Originally Posted by Zebidee View Post
    Easiest thing is to test them with an ESR meter in-circuit (no need to de-solder)....
    An ESR meter is something I've looked at needing for a while, but I've avoided because I haven't been familiar with the quality models to use. I see a lot of $10-20 options on Amazon and eBay that are clearly junk and can't be used in circuit. And then a lot of extremely expensive options.

    The kits you referenced look reasonable (about $80USD for the kit to assemble the Blue ESR Kit). As I'm in the U.S. and you're in Australia the ones you have probably wouldn't be as cost effective to ship over here. I think I'll look into getting one of these kits soon and have that resource available to me.

  6. #196

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    Yeah, caps are cheap and most even a lot less than $2 each. "Shotgun" replacement of cheaper suspect components is fine so long as you enjoy de/re-soldering a lot and have a good iron.

    $US80 for the Anatek Blue ESR is pretty cheap for the work it'll save you. These days, in the second half of my life, I value my time and frustration levels at least as much as money. It's also good for finding cold solder points and testing batteries.

    BTW I'm an Aussie but in Thailand ATM. But yeah, international registered post costs a bit.

  7. #197

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    There is a flip side to this, and while ive not done this in a TV set ive done a few very high end CRT projectors top to bottom, and there is no question the stability of the sets improved in MOST cases, especially with Barco projectors.

    Not that Barco used crap capacitors, but the Panasonic FCs and FRs are obviously better than what they did use.

    I have no clue why they wouldnt use "the best" and take a "no compromise" aproach with a CRT projector that when first available here was around $118,500 AUD, but obviously there was many places where they used a $0.30c cap instead of a $1 cap, and overall set stability ( and in at least two cases, reliability ) suffered.

    Ive have 2 of these Barco 9" monsters here and ive done all capacitors in both with the same results, so its not just a one-off fluke.

    Sony consumer grade sets didnt typically suffer bad capacitors, but improvements can be made, simular could be said for Panasonic.

    NEC were absolutely plagued with bad capacitors in the early to mid 90s, ive seen zero hour new old stock NEC 9PG CRT projectors dead out of the crate just because their Nichicon caps start leaking with age, but worse yet they destroy the boards at the same time. A lot of domestic consumer grade NECs suffered the same issues, just on a lesser scale.

    The amount of dead LG and Samdung LCD and plasma sets i repaired back around 8-10 years ago was nothing short of a JOKE. They almost always had capacitors installed that were not up to the task, and often not a high enough voltage rating to cope with life. Its one thing to have them leak after 15 years, but there was no excuse for that shit, its nothing short of pathetic.
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  8. #198

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    @neo-geo_man, yeah I hear you, many cheap monitors would def benefit from a complete re-cap within 5-10 years. Crap caps are a major failure point and definitely a problem esp with some brands, not just monitors. For example, often power supplies crap out with bad caps.

    Like you say, some original caps are just not good enough so often a good idea to replace with something higher rated for voltage, temp etc. Even so, many caps are perfectly OK, no need to change them out. Some caps get stressed out, some are just fine. ESR meter just makes it all a lot easier. Would be especially handy when doing a bunch of the same monitors like those Barcos as you'd work out where the stress points are.

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