Re: Samsung LN40B500P3F screen goes black every few seconds
I finally got the replacement part in today. I soldered it onto the board and put the board back in to the TV. No more flickering backlight, BUT now it sounds like an electric razor due to buzzing from the board whenever the backlight is on.
It's hard to tell which transformer it is coming from, but I used a non contact style probe to narrow it down a bit. The noise is loudest in the area's highlighted in yellow. The thermistors also get pretty warm, not sure how hot those should get. I let it run like that...
mike_drz
Member
Last Activity: 02-04-2019, 10:16 AM
Joined: 05-18-2017
Location: Toronto, ON
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Re: Samsung LN40B500P3F screen goes black every few seconds
Thanks for this link, I ordered from an ebay seller that uses "speedpak" whatever that is, but customs still holds on to it just to be difficult sometimes. I LOVE digikey, I have digikey boxes all over the place here. lol
Here's an interesting link regarding crazy shipping delays, Canada Post blames Customs, and customs blames Canada post.
[url]https://calgary.ctvnews.ca/canada-post-reveals-it-is-the-reason-for-lengthy-parcel-delays-1.3447438[/url]Re: Samsung LN40B500P3F screen...Last edited by mike_drz; 07-22-2018, 05:09 PM.Leave a comment:
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Re: Samsung LN40B500P3F screen goes black every few seconds
Thanks for the advice. Canada customs can be crazy at times. Sometimes I get Chinese packages in 2.5 weeks, other times it's 4 months. All the north american sellers have this at $20 vs $5 from hong kong. I might need a backup TV in that time, hah...Leave a comment:
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Re: Samsung LN40B500P3F screen goes black every few seconds
Thanks RJ! I'll give it a shot, worth a 6 dollar gamble. haha I'll check other components while I wait for the part to come....Leave a comment:
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Samsung LN40B500P3F screen goes black every few seconds
Hello folks, as the title states, the TV's picture will drop to a black screen every few seconds and the picture will come back intermittently. There is audio the whole time, and it's not a signal issue, as it does this in all modes even with the signal cables unplugged.
I've opened it up and found that one of the inverter transformers was getting very toasty, it had black char marks (part QGAH02095). If I just replace this part is it likely to just fail again in the near future? Does it have anything to do with the light tubes? If I need to replace the tubes, how would I go about... -
Re: Pioneer XR-A670 cd changer mechanical issue
No dice, the unit plays fine for a little bit, and then starts rubbing again. I tried pulling the spindle up, but it's friction fit pretty tightly. I used a wooden block with a screw head sticking out of it that goes on top of the spindle. Then I pulled up on the spindle head. It wouldn't budge, even when oiled. I was afraid I'd bend the spindle head.
This thing is all plastic, it doesn't seem to be pioneer's best work. It even uses screws as shafts, if you tighten them too much, things will bind.Leave a comment:
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Re: Pioneer XR-A670 cd changer mechanical issue
It looks like a combination of things causing the problem. I took the mechanism apart for the first time. The black rubber floats are chalky in colour. I took them all out, and sprayed them with some silicon spray. The motor shaft does have some vertical play on the shaft. The bottom end, or end cap of the motor is sealed. I can try slide the top of the spindle up a bit.
The tilt mechanism appears to just be a cam, when the cam unlatches, there's a spring that pushes the whole thing up and level. I stretched...Leave a comment:
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Re: Pioneer XR-A670 cd changer mechanical issue
RJ, it's been a while. How have you been? That's something else I'm going to check out. I have put it on the back burner for now, as the workbench has a wood working project on it right now.
From what I recall, the spindle looked like it was on a bit of an angle. It's as if the whole assembly is not coming up all the way. It's on a spring from what I see in the service manual. I'll take a look at it soon enough; and let you guys know.
Mike...Leave a comment:
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Re: Pioneer XR-A670 cd changer mechanical issue
Chungalin, that is genius! That never came to my mind at all while looking at it. I will take it apart and give that a try. Thanks so much for your advice
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Pioneer XR-A670 cd changer mechanical issue
Hello all, I've been fixing up an old cd/tape/stereo bookshelf type unit. I cleaned the rail for the laser and greased it all up. That fixed the first issue where it wasn't reading the disc. To my great joy, there's another problem.
The CD clamp rubs against the top assembly, causing the CD not to spin, or make noise if it does. If I push down in the middle of the assembly, then it'll play just fine. I tried bending the plastic, and it'll work for a few minutes. Now it's back to not working.
Am I missing an adjustment anywhere? Is there supposed to be a rubber part... -
Re: Toshiba M-9485C VCR
For anybody who's interested, the VCR was fixed. It had one bad head, and a problem with the audio head alignment for some reason. Got it fixed for a reasonable price.
For anybody from the Toronto area in Canada, take your gear to Oscar from AMI electronics, he really is great. He's one of the few guys around that still does board level repair on anything you bring him.Leave a comment:
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Re: Toshiba M-9485C VCR
I spent some time farting around with the tape adjustment and back tension. I got the crinkle reduced. However it's still there. I also only get signal from one head from what I can see on the scope. I definitely think it's a time issue now.
There is an older service guy I called today, I told him the issue and he said he can take a look, free estimate. We'll have to see if it's feasible. Might be cheaper to just buy a used head. This one is pretty worn....Leave a comment:
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Re: Toshiba M-9485C VCR
When I first took this unit out of storage, the head would make a crunchy noise, when I spun it by hand. It got better with time, but always was noisy when it was spinning.
When I had the head apart, I cleaned those air groves with a tooth pick. They were clogged up. Maybe that's what's changed the tape tension. I also had the idler motor apart when changing the idler wheel. Don't know if there could be a timing issue with that one. I also marked that rotor before taking it off just to be safe....Leave a comment:
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Re: Toshiba M-9485C VCR
Thanks RJ, I'll just have to hope the head isn't broken, that'll be game over. I won't adjust the heads, they are in the upper head with hex screws. I've left those be the way they are. Maybe one got bent while I was taking it apart who knows. The head always had some drag to it though, even before I took it apart.
The felt on the copper band seems fine, but the band itself is really flimsy, doesn't feel like metal anymore. It has more of the tension of plastic after 27 years....Leave a comment:
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Re: Toshiba M-9485C VCR
Today it started acting a little better, I found the crinkle is starting around the capstan shaft and pinch roller. The top is folding over. The back tension band on this machine is very old and worn out, the little copper band.
The head is still making noise as if something is rubbing. When I put that collar back on the head shaft, did I need to add pretension? There's a little wavy spring washer type thing, just below the collar.
One of the heads looks like it's lower than the rest, and is close to the bottom cylinder....Last edited by mike_drz; 05-26-2017, 09:52 AM.Leave a comment:
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Re: Toshiba M-9485C VCR
Thanks RJ, the drum assembly is all slotted with guide pegs etc, it can't go in wrong. Thanks for all the tips, very valuable info. Yeah the picture is quite crappy, and does cut in and out. There are some lines too, but I'm using a small cheap monitor, so I can't tell right now.
The tape sounds like it's almost making a grinding noise against the drum, and the drum slows down. A few seconds later, it'll run smoother, with just the crunchy tape sound. Not very good at all, I swear I didn't touch the tape path until I heard that...Leave a comment:
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Re: Toshiba M-9485C VCR
I took some scope shots, The switch is at 2v/div @ 10 mS, Envelope is 20 mv/div @2ms. CTL is 0.5 volt DC, 2H is 5 volt DC.
The shots didn't come out super well, because of the frame rate....Last edited by mike_drz; 05-25-2017, 07:59 PM.Leave a comment:
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Re: Toshiba M-9485C VCR
I changed the idler tire too, everything else was the same. I adjusted the tape path just now, it plays okay for a bit and then starts to grind on the tape again. The envelope on the scope is no where near what it was before. It's not catching on any guide posts or anything. It enters straight, and starts to crinkle when leaving the drum. The back tension and everything else are the same.
Would the switching point show up on the scope as being off?...Last edited by mike_drz; 05-25-2017, 07:32 PM.Leave a comment:
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Re: Toshiba M-9485C VCR
RJ, yep you called it. I put it back together on the marks the grub screws left on the shaft. Must still be a bit off though, I guess I create more fun times.
It plays but it crinkles the tape and cuts out, it also sounds like the motor is changing speeds sometimes. Is the only way to fix it trail and error changing the set screws?Last edited by mike_drz; 05-25-2017, 07:08 PM.Leave a comment:
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Re: Toshiba M-9485C VCR
Thanks, I couldn't get it apart without taking that collar off, to get it all apart. I marked everything, but we'll have to see if it still works after. That orange tape rust got everywhere....Leave a comment:
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