Re: Help with Tatung TLM-1905 LCD no power at all
diode check 470 one direction and 143 the other ohms 89.8 one direction and .46 on 20k scale other direction. By the looks of it I did not change that little cap. I will see if I have one. It doesn't look bulged in person
jbshocks
Member
Last Activity: 03-05-2021, 12:04 PM
Joined: 01-06-2013
Location: Clawson
-
Re: Help with Tatung TLM-1905 LCD no power at all
see if this picture is better...Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
removed fuse. no voltage on either pin or across them. I will try to get another picture later.Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
So un solder the fuse and test for power? I ca do that after work but I don't think there will be anything. There is no sign of power on that side of the main yellow transformer....Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
The 3.5 I get on the little 8 pin chip sg3842gs that I replaced. I also get 3.5 across the small 22uf cap. I get nothing on any pin of the white connector going to the other board.Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
what about this little chip? It is P721F, call a switching power supply. How would I test it. Could it be the cause? I have power on the two legs with in the zone that power works....Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
I changed out the chip and the little 22uf cap. Symptoms the same. Only difference now is that I get 3.3v between pin 5 and 7. Still no voltage on board connector.Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
Thanks Rtech, I will order one up from digikey and give it a shot.Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
diode reads 500 one direction and nothing in the other in diode test mode. This is out of circuit. I could easily change out the chip. My concern is that I have no voltage on the chip vccLast edited by jbshocks; 02-04-2013, 11:46 AM.Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
FYI, found this thread. [url]https://www.badcaps.net/forum/showthread.php?t=14042[/url] Same power supply same symptoms. I tested pin 5 to 7 nothing. in fact tested pin 5 to all pins. Only pin 3 was non zero and fluctuated between .8 and .9v. Unfortunately no resolution was posted.Re: Help with Tatung TLM-1905 LCD no...all pins. OnlyLeave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
chip says sg3842gs. I can see on the board it goes to pin 7, verified with an ohm meter.Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
across the big cap is 169 v DC. Here is a little better picture. I don't have a very good camera....Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
Measuring across c109 (small cap) 0 v dc...Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
it is c109 and it has 64.5 on each leg to ground.
Also testing with meter on 200 vdc the area in orange is the only area of the board with any power at all....Last edited by jbshocks; 02-03-2013, 02:29 PM.Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
on 200v DC tested ground to each side of F1. Nothing. 0. Also tested ground to each pin connector. All 0. Ground screw to input side of transformer 63 v. I will try to get better pictures and read the guide....Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
Where circled in black I got voltage. Red circles, nothing....Leave a comment:
-
Re: Help with Tatung TLM-1905 LCD no power at all
F1 checks fineLeave a comment:
-
Help with Tatung TLM-1905 LCD no power at all
I have a Tatung LCD monitor that does nothing at all. No LED on power button nothing at all. It had some bad caps which I replaced and that did nothing. I hooked the back lights to a different brand power supply and the display itself works fine. With power plugged in I have voltage on the large yellow transformer on the plug side nearest the big filter cap. Around 60v. I would think that mean the bridge rectifier is fine as well as filter on the output side of the transformer I have nothing. No voltage at all. I checked the resistance on the output and it is roughly 1 ohm. Would that indicate...
No activity results to display
Leave a comment: