Re: RCA LED65G55R120Q No Backlight
I assume the low voltage string is bad?...
zacheriaj
Senior Member
Last Activity: 01-31-2019, 01:32 PM
Joined: 01-12-2014
Location: Madison, WI
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Re: RCA LED65G55R120Q No Backlight
Sorry for the delay. I'm in WI and its been a rough week! Finally got voltages for you.
PS-5Vs: 5.1v always
ADJ-BK: 1.6v when turned on, drops to 0
5V+5V: 4.9v once powered on, then drops to 0
LED Connector (left to right)
+: 285V drops to 0 in five seconds
-: no reading
+: 135V drops to 0 in 5 seconds
-: no reading...Last edited by zacheriaj; 01-30-2019, 04:59 PM.Leave a comment:
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Re: RCA LED65G55R120Q No Backlight
What connection should I remove on the main board?...Leave a comment:
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RCA LED65G55R120Q No Backlight
hello, I picked this TV up for free and started to diagnose it. I assume either a main board issue or shorted LED's. When I power it on, my voltages come up correctly and the LED's light for a split second. Then the entire system shuts down. No voltage anywhere. I assume shorted LED's forcing the PSU into protect so I disconnected the LED connector, powered on again, and the same issue occurred. Voltages came up for a second and then everything shut down. Any ideas? -
Re: Sanyo DP46819 Picture Issues
That is what I assumed. They have it listed but none in stock. Do you know which one is the gamma chip and if it's worth the gamble that it's an isolated issue?...Leave a comment:
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Re: Sanyo DP46819 Picture Issues
Thank you. What exactly am I testing for, how, and what would cause a gamma issue?...Leave a comment:
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Re: Sanyo DP46819 Picture Issues
This is the SJ photo for the t-con. It is the exact one, I don't have the tv with me right now....Leave a comment:
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Sanyo DP46819 Picture Issues
Picture is solarized as shown in photo. I have cleaned t-con connections, re-flowed the ground pins on the t-con connector, and the issue persists. Any ideas? SMPS tests perfectly. Also cleaned the t-con connector on the main board. TV has sound and video, all other functions are fine. Customer stated that the picture was dim so he used a can of air duster on the set and now this picture problem started.... -
Re: Rotel RMB-1075 blows left front fuse
I have. And I don't think that anyone here would question ti the quality or validity of Digikey components....Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
Thanks for the tip RJ. But I beat you to it
didn't really need but a hair of adjustment...
Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
Replaced the bad output transistors and R425. Didn't see any other issues during testing. Unit powered up fine and passed all tests. Once it warmed up, I let it run about 60-70% for 45 mins with no issue. Customer is thrilled. Thank you everyone for the help!...Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
Thank you RJ. I didn't initially see the value on the schematic.Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
It is shown in this picture. I have it pulled now but can't see the middle color codes....Last edited by zacheriaj; 06-22-2016, 10:28 PM.Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
I tested everything on the board. Driver transistors are ok. diodes are ok. The only other fault is the R425. Any idea how to find the value for replacement? I'm thinking it's either 33ohm or 330 ohm but no idea on the wattage.Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
Found direct replacements here. I will test the drivers tonight as well.
[url]http://www.digikey.com/product-search/en/discrete-semiconductor-products/transistors-bipolar-bjt-single/1376376?k=A1492[/url]Re: Rotel RMB-1075 blows left front ...?k=A1492[/url]...Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
VR401 is fine and shows no signs of stress. I found R425 toasted but everything else is testing ok. Now I have to find the values of the output transistors so I can order some. I think i have it in the parts list though....Last edited by zacheriaj; 06-22-2016, 11:12 AM.Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
I removed the left side amp board and isolated the emitters on the output transistors. I found Q414 dead short from collector to emmiter. Depending on cost, I may replace them all. I'll update when I can on the outcome....Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
Yes. Every other channel works. I have the new fuses on hand but I didn't want to risk damaging any other channels and also used the good fuses during testing. Also, being that the amp is getting some age to it, I decided to order the new style time delay BelFuses through Digikey. Figured i'd replace all at once as soon as I figure out the issue with channel 4...Last edited by zacheriaj; 06-21-2016, 08:19 PM.Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
Can you give me contact points for this?...Leave a comment:
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Re: Rotel RMB-1075 blows left front fuse
No shorts on those at all. Resistors are all good. Is it possible that the fuse blew while testing because I don't have the other channel fuses installed?...Leave a comment:
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