nick3092
Member
Last Activity: 11-09-2022, 01:57 PM
Joined: 04-14-2020
Location: Milwaukee, WI
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Mid/late 80's Nichicon Yellow Caps
I recently acquired a set of Bose Roomate speakers from the mid to late 80's. Basically the right speaker cabinet is completely passive, and the left one has the power transformer and amplifier circuit in it. Out of curiosity, I opened it up to see what the circuit looked like. Looks like they used all Nichicon VX (2x 4700uF/16v for smoothing off the bridge rectifier), a couple random Nichicon SE series sprinkled on the board, and what really caught my eye - 2 yellow sleeved Nichicon caps (both 1uF/50v with no real series marking. Below are pictures of the caps. The only thing not shown in these... -
Re: Advice on replacing some mid80's caps
Thanks for the advice. I actually just finished the recap last night. I used a mix of Nichicon and Panasonic. I usually stick to those two, but have used Rubycon and UCC in some applications when needed. Nothing against them, I just try to stick to two brands so I'm not spending hours comparing caps across 4 vendors.
I usually stick to FC or FR when I go with Panasonic for general caps. I also used some Nichicon UPM and UPJ for some caps where FC or FR's weren't an option.
In general, I always try... -
Re: Advice on replacing some mid80's caps
Except that is sam[B]wh[/B]a. I'm talking about sam[B]hw[/B]a.
[ATTACH]214308[/ATTACH]
Plus I'd guess that datasheet is at least 2 decades newer than this cap, at least.
I've only worked on one other CRT before, and it did have a schematic and parts list. It had a cap on the deflection board that was also yellow jacketed (but at least it was a brand name cap), and was called out as being low leakage on the parts list. Can't be a coincidence this board has one too. But I could be wrong....Last edited by nick3092; 06-16-2020, 07:23 PM.Leave a comment:
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Advice on replacing some mid80's caps
I recently picked up a an old Apple //c color monitor from 1985. I noticed the color controls were quite touchy, so I opened it up to see how hard it would be to get the pots out to clean them. And I saw a cap that looked like the top was bulging pretty good.
So out the logic board came, and now I'm looking to recap the whole thing just to be safe. Unfortunately, Apple didn't believe in board level repairs, so schematics are non existent. I had to go through and inventory it manually, and have no idea where in the circuit any of these really are to even guess what type I should... -
Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
Wrapping this thread up. The culprit turned out to be IC007, the defection processor. Apparently Sony used this same design (N3 chassis) in several of its own and re-branded monitors, and it was quite common for this IC to fail in that chassis and cause these symptoms. I found an NOS one for a reasonable price and found someone local who does SMD rework for a reasonable price as well.
Monitor is now happy, and so am I. Thanks to everyone for their input.Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
Not sure if anyone is still following this, but I have a (non) update. Since I don't really know what to check next, I went ahead with the only thing I know how - recapping the A board (RGB/video amp). Unfortunately, seems to have made no difference what so ever. The only board left I haven't replaced the electrolytics on is the L board (V stat, H stat, LLC, Geo magnetic sensor). I highly doubt the issue is there. But I had to order some other parts, so I did order those caps as well. I don't have anything to lose by recapping...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
Since I haven't got any more suggestions on what to look at, I went ahead with recapping the power supply board since I had the caps on hand. I was able to twist the negative terminal on the large filter (C611 330uF/450v) so that it fit the PCB. I didn't expect it to actually fix anything, and it didn't. I bought the wrong physical size caps for the 15 and -15v rail filters (C675, C677 2200uF/25v), so I left those as is. I don't think that's the issue anyway, the scope didn't show those rails looking that bad.
But...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
Thanks, I did find a link to the service manual that I posted back at the beginning of the thread. I did also download the service manual for that eBay monitor found by R_J. The deflection board is almost identical from taking a high level look at it.
I did a copy and paste of just the capacitor list for each into Excel and compared them. My monitor has 3 caps the other one doesn't. But otherwise all the references, descriptions, and values matched up. The part numbers differed in probably half the cases, but they...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
I was wondering if there might be a common fault in these monitors. When mine first started acting up, I had searched trying to find a solution. I never found anything, other than someone posted over on the CRT Gaming section of Reddit: "I bought this guy so I'd have something to play games on until I can either repair my SGI GDM-5011P's deflection board..." Which made me wonder if all these had some kind of defect on the deflection board. Maybe a bad batch of some part they used? Of course the million dollar question...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
The post on the arcade forums? Those values were from me trying to bench test the power supply board only. It seems when the bard is out of the chassis, the 200v rail runs high.
I get that linear power supplies run high with no load, so that can happen. But I thought this was SMPS and voltages would be spot on. When I put it in the chassis though, the voltages are all reasonable. So I gave up on trying to bench test the power supply after the post on the other forum.
Here is what I posted earlier in...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
I am able to get to IC703 and Q501/503 by using a piece of 22ga wire to extend my probe into the vent holes. I did have the wire pinched between my fingers when I took these, but I don't think it affected the reading at all. If they look funny, I can try to take them again without holding the wire to navigate through the vent holes.
I took the IC703 print at 5ms like the others. But at 5ms Q501/503 just looked like solid line. So I backed down to 5us, and you get several square waves. Not sure how these look, as...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
Ok. Do you have any suggestions what to probe with the scope next? This level of troubleshooting is way above me. And I've never done anything with video signals before. So I really appreciate all the guidance so far. Which means I'll need some explicit directions on what/where to check next.Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
Sorry if I missed the suggestion about trying different resolutions. The laptop I'm using allows me to pick 3 of them when mirroring the laptop display: 1280x800, 1024x768, and 800x600. The issue exists in all 3. I don't think it looks any better or worse in any of them.
Switching to monitor only output, I can also select 1152x864, 1280x960, and 1280x1024. Issue also occurs in all 3 of those resolutions as well. Doesn't seem any better or worse than the other 3.
Does that help narrow down where to check...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
Any other ideas of what to look at? I know film/mylar caps are generally very reliable. But would there be any chance one of them could be starting to fail and causing this? Looks like there are around 30 or so on the deflection board.Last edited by nick3092; 05-01-2020, 02:46 PM.Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
I can try and see if I can make up some kind of mount to position the deflection board so I can get to the back, if needed. But it's not going to be easy. And I'm assuming straight up replacing the board is out of the question, since it's probably made out of unobtanium these days. So repair is probably my only option.
A friend of mine offered a suggestion if I need to probe IC703. I could just take a piece of solid strand wire and use it to probe through the hole in the shield, and connect the other end to my probe....Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
I noticed when doing pincushion and horizontal size adjustments, the peaks and valleys of the ripple tended to go up and down. I noticed on the horizontal adjustment there were two larger valleys on the bottom half of the right side that never changed, even though almost every other part of the ripple did. Not sure if that points to anything. But it seemed odd given the behavior of the rest of the ripple.
[ATTACH]211554[/ATTACH]
Also, if IC703 is still of interest, this is where it is. I was thinking...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
The deflection board hangs vertically, and the wiring harnesses are not really long enough to be able to lay it down. Trying to prop it up would be virtually impossible. Not to mention the fact it integrates the tray and another big heat sink in the back of the tray into the heat sink on the top side of the board.
I'll play around with the geometry settings tomorrow morning before work and report back....Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
It's highly unlikely I missed a cap on the D board. I only ordered what was on the part list, and had nothing left over. Plus I printed out the part list and the PCB layout and checked them as I worked. As I removed the cap, I checked it off the list. Once I put the new one in, I X'd out the location on the PCB layout. Plus there was a layer of dust on everything. I just visually inspected the board, and all the caps are all dust free now.
IC703 is a problem. It's an SMD chip located on the back side of the board....Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
I took a snapshot of the blue pin on CN402. Despite changing the trigger to video, and trying to find the trigger, the best I could do is get it to be "twitchy". Meaning it was kind of stable, but looked like it would occasionally jerk left or right. Trying both polarity options didn't seem to make a difference.
CN402 - 6 B_IN
[ATTACH]211502[/ATTACH]
CRT Image
[ATTACH]211503[/ATTACH]Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
I took a snapshot of the blue pin...Leave a comment:
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Re: SGI GDM-5011P CRT Monitor (Sony Trinitron) Help
I downloaded a GIF of the color bars, and ran it full screen on the laptop while scoping IC403 on the blue in and out pins. I made sure after using the auto function to change both to 5ms as suggested, but it didn't look stable. It was rolling horizontally on the scope, and just looked like some almost solid blocks. So just to be safe, I also took prints at 5us as well. Which look more like detailed waveforms. Hopefully at least one set of these is right.
IC403 - 1 B_IN - 5us
[ATTACH]211498[/ATTACH]
...Leave a comment:
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