Mitsubishi cs-2710ra vertical problem
in [Repair]
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From: Tech Data on 28 Aug 2006 21:09 ladybug wrote: > Will regular 1.2 ohm resistor work as a burned current limiter? > > http://www.mouser.com/ > > > Mouser Part #: 660-CF1/2L1R2J It'll work just fine. www.techdata-kicksass.net
From: Ohmster on 4 Sep 2006 05:13 "ladybug" <natayz(a)gmail.com> wrote in news:1156809810.350898.9610 @i3g2000cwc.googlegroups.com: > I got new caps but TV seems to be completely dead now. I don't have > power on the main high voltage transformer so tube gets nothing. No > cathode light, no high voltage... I checked the fuses, no problems > there.. I can hear power relay clicking when I press power button on > the remote, so controls are good. Any ideas? Gosh I tried like hell to get you away from this thing, Ladybug. After all the work you put into it, now this. (And it is STILL just an old 27" TV set!) ...sigh. "Any ideas?" ...yeah, pitch the set and be done with it already. But I assume that is still not an option, yet? Is horizontal output transistor shorted? This is a large, usually black transistor (Black plastic, maybe metal back on it, with three legs on it, attached to a large metal plate of some kind to dissipate the heat.) over near the flyback transformer. If you put an ohmmeter probe on the collector (Center leg) and the other probe on the emitter (leg on the left side) does it read a very high value of ohms or is it shorted (Very low ohms, usually 1 ohm or less.)? If shorted then you have opened up something in the power supply circuit that feeds the B+ to the horizontal output circuit, could be a resistor or fuse (Some fuses look like small resistors, attached with wires to the board.) and the horizontal output transistor will have to be replaced. Could also have been caused when you put the CRT board back on with bent pins on the CRT. Now that they are straightened out, the set might work if you find out what happened to your B+ for the horizontal output circuit. Seriously though, if the set is not fixed really soon with just a few last things to do, consider cutting your losses and running on this. How much more kicking can your heiny stand on this job? -- ~Ohmster
From: ladybug on 4 Sep 2006 22:42 Ohmster wrote: > "Any ideas?" ...yeah, pitch the set and be done with it already. But I > assume that is still not an option, yet? > > Is horizontal output transistor shorted? This is a large, usually black > transistor (Black plastic, maybe metal back on it, with three legs on it, > attached to a large metal plate of some kind to dissipate the heat.) over > near the flyback transformer. If you put an ohmmeter probe on the collector > (Center leg) and the other probe on the emitter (leg on the left side) does > it read a very high value of ohms or is it shorted (Very low ohms, usually > 1 ohm or less.)? > > If shorted then you have opened up something in the power supply circuit > that feeds the B+ to the horizontal output circuit, could be a resistor or > fuse (Some fuses look like small resistors, attached with wires to the > board.) and the horizontal output transistor will have to be replaced. > Could also have been caused when you put the CRT board back on with bent > pins on the CRT. Now that they are straightened out, the set might work if > you find out what happened to your B+ for the horizontal output circuit. > > Seriously though, if the set is not fixed really soon with just a few last > things to do, consider cutting your losses and running on this. How much > more kicking can your heiny stand on this job? > -- > ~Ohmster Thanks for you help, Ohmster. Actually I found myself liking to fix this old TV. Kids have smaller back up TV for now so there is no rush to get it fixed right away. I got a schematic from the local library and it proven to be a good reference. I figured out why power was lost. Firstly a diode D553 ES-1F appears to be bad and reads open in both directions. I temporary replaced it with a rectifying diode that holds 600v. I found that I have 23V output and other voltages untill pin 8 of LA7838 gets connected. Once I connect it all voltages from transformer dissapear, and cathode light goes off. I suspect that I need a new LA7838... Will try to get a replacement shortly.
From: Michael A. Terrell on 5 Sep 2006 00:42 Ohmster wrote: > > Seriously though, if the set is not fixed really soon with just a few last > things to do, consider cutting your losses and running on this. How much > more kicking can your heiny stand on this job? Why don't you go create news:sci.electronics.throw.it.away so you can play there with the other people who are too eager to quit every repair attempt? -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida
From: ladybug on 21 Sep 2006 15:30
Just wanted to let everyone know that I got the TV fixed. Parts took a while to come. It was bad chip LA7838, an open diode, couple of burned 1.2 ohm resitors, and a dozen of leaking caps. Thanks everyone for the support and help and boo to nasayers. Michael A. Terrell wrote: > Ohmster wrote: > > > > Seriously though, if the set is not fixed really soon with just a few last > > things to do, consider cutting your losses and running on this. How much > > more kicking can your heiny stand on this job? > > > Why don't you go create news:sci.electronics.throw.it.away so you can > play there with the other people who are too eager to quit every repair > attempt? > > > -- > Service to my country? Been there, Done that, and I've got my DD214 to > prove it. > Member of DAV #85. > > Michael A. Terrell > Central Florida |