Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
It's a KV27TS20 almost 19 years old. Don't worry...it's been superceded
with a nice Sony HD LCD TV. But I figured I would at least take a look before tossing it. And fix it if it's something simple--even if it only benefits the person picking up from curbside. Symptoms: Totally dead. Does not respond to front panel or remote power button. No relay clicks...no degauss buzz. Some years back another similar looking Trinitron, only slightly younger, died due to a failed regulator chip but you'd still hear the power relay click and the degauss buzz if trying to power on after a long enough interval. I fixed it with a new regulator chip. That model had a separate power board but this one does not. Does the "always on" power on this one come from the main regulator or someplace else since that would seem to be the first place to look. I don't have a schematic. I saw two fuses but they checked out ok. |
#2
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
Steve Kraus wrote:
It's a KV27TS20 almost 19 years old. Don't worry...it's been superceded with a nice Sony HD LCD TV. But I figured I would at least take a look before tossing it. And fix it if it's something simple--even if it only benefits the person picking up from curbside. Symptoms: Totally dead. Does not respond to front panel or remote power button. No relay clicks...no degauss buzz. Some years back another similar looking Trinitron, only slightly younger, died due to a failed regulator chip but you'd still hear the power relay click and the degauss buzz if trying to power on after a long enough interval. I fixed it with a new regulator chip. That model had a separate power board but this one does not. Does the "always on" power on this one come from the main regulator or someplace else since that would seem to be the first place to look. I don't have a schematic. I saw two fuses but they checked out ok. Just follow the pc trace and see where the standby voltage is developed. Shouldn't be too long a path. How much experience do you have repairing tv's? Good luck. -- David Farber David Farber's Service Center L.A., CA |
#3
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
Hi Steve,
Steve Kraus wrote: It's a KV27TS20 almost 19 years old. Don't worry...it's been superceded with a nice Sony HD LCD TV. But I figured I would at least take a look before tossing it. And fix it if it's something simple--even if it only benefits the person picking up from curbside. Symptoms: Totally dead. Does not respond to front panel or remote power button. No relay clicks...no degauss buzz. first you should look up the chassis number of this set on the internet. Once you it, check if you can find a list with common issues with this set and their remedies. Since it is a Sony set, it should be easy to find. At least, that's my experience with these. I don't have internet access now and I'm writing this post offline with my handheld, otherwise I'd look ot up for you. A very common website for such repair information was http://eserviceinfo.com, I don't know though whether the site is still up and running. I'd also check good old http://repairfaq.org. Good luck and greetings from Geneva/CERN, Adrian |
#4
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
Thanks. I've tried to verify standby power and I do get 5V in once place
it's labeled. I figured if I can find something simple like a bad diode I'd fix it but since I have no use for the set anymore I don't want to put too much effort into it. I'll do a bit more searching before surrendering. |
#5
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
The plot thickens. I'm limited in what I can do with the main board hooked
up (about 20 connectors) and with it out of the set I'm not sure if my live tests are valid. Anyway, I put it all back together, attempted power again and still dead of course. But I left it plugged in. About 20 minutes later I heard the power relay clicking and the LED flashing. I pushed the power button a few times and the set came on. I'm guessing the defective standby power may eventually charge a filter cap to the point it can pull a relay in but in so doing the voltage droops again unless one happens to be hitting the power button at just the right moment when main power can take over. So it really must be something quite simple. Or not. We shall see. I've not been able to trace things enough to find fault but maybe I'll have better luck if I can track down a schematic. |
#6
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
On Feb 18, 12:35*am, Steve Kraus
wrote: It's a KV27TS20 almost 19 years old. *Don't worry...it's been superceded with a nice Sony HD LCD TV. *But I figured I would at least take a look before tossing it. *And fix it if it's something simple--even if it only benefits the person picking up from curbside. Symptoms: *Totally dead. *Does not respond to front panel or remote power button. *No relay clicks...no degauss buzz. Some years back another similar looking Trinitron, only slightly younger, died due to a failed regulator chip but you'd still hear the power relay click and the degauss buzz if trying to power on after a long enough interval. *I fixed it with a new regulator chip. That model had a separate power board but this one does not. *Does the "always on" power on this one come from the main regulator or someplace else since that would seem to be the first place to look. *I don't have a schematic. *I saw two fuses but they checked out ok. Given the age involved, I'd just change the electrolytic caps on the psu secondary and go over the soldering in the psu and line stage. The symptoms suggest a cap or a cracked joint. -B |
#7
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
Sony Trinitron KV27TS20
Good news. Never did find a schematic but Googling I found a mention of a capacitor, C605. This is an electrolytic 22uF* rated at 250V. It didn't look bad but unsoldering it it does look a little bulged at the bottom. I didn't have anything like that laying around but figure a bigger cap in a PS section might be worth trying I temp wired a 680uF* / 200V and with that in the circuit the TV starts and behaves normally. So I need to find one closer in value if not the exact replacement. I measure 140V across it. It's there even with the set is off so obviously standby related. I had no idea standby voltage was so high. I suppose it could be from the wrong value; without a schematic I don't know if it would do that. But that does indeed seem to be the source of the problem. * microfarad of course. Can't get a mu on here. |
#8
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
* microfarad of course. Can't get a mu on here.
Here's one for future use: μ Sylvia. |
#9
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
If you were running Windows, you'd be able to get it from the Character Map
applet. And if you can also enter it directly by pressing ALT+0181. |
#10
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
Sylvia Else wrote:
* microfarad of course. Can't get a mu on here. Here's one for future use: μ Thanks Sylvia but that's not reproducing correctly here (running Xnews on Windows XP). I tried using one and saw it wasn't going to work. |
#11
Posted to sci.electronics.repair
|
|||
|
|||
Sony 27" Trinitron Dead
William Sommerwerck wrote:
If you were running Windows, you'd be able to get it from the Character Map applet. And if you can also enter it directly by pressing ALT+0181. Hmm...that one may work. µ Thanks. I'm not sure what one I tried (pasting in from elsewhere) but probably the same thing Sylvia was suggesting. I don't know if others see that one correctly but I didn't. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
sony 29" trinitron dark, no picture | Electronics Repair | |||
sony trinitron 32" | Electronics Repair | |||
SONY KV-32S40 32" Trinitron screen distortion bowtie | Electronics Repair | |||
Dell (sony) trinitron P991 monitor not "starting up" | Electronics Repair | |||
Sony WEGA 32" Trinitron TV | Electronics Repair |