If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
Hi guys.
Just moved into a new flat (thanks GHA!) and need a TV.
I found a JVC 32" which was being thrown out for bad PSU, but the panel seems fine. Luckily got to it before the nice people who remove these things smashed the screen...
Reckon there is any way to test then fix it for not too much wonga? Its totally dead, no sign of life and no standby light..
Last time I hooked up 9 SMPS's in parallel to generate the 9 power rails it needed then ordered a broken TV and asked for just the boards. 2+ years later, works well.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
I have a view sonic which still works after i replaced the main filter caps on the SMPS, these viewsonics were notorious for blowing out these caps which were spec'ed poorly in ESR. Havent had a problem in 1+ year.
Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
I would second the just replacing the filter caps, all of the dead monitors I have found (admittedly much smaller monitors) have had bulging caps which simply needed replacing.
I had one friend with a larger lcd panel (about the size of yours) which had a bad self start circuit on the psu,which was due to a shorted zener diode, which in turn took out a bridge rectifier. If you aren't getting anything out of it I would try and trace down the startup 'bootstrap' circuitry and look for issues. If you are feeling really brave you can try just feeding voltage directly into the supply rail for the switching circuitry as well. Any luck locating a service manual? The aforementioned TV actually had a complete schematic of the power supply in it
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
... wrote ...
I would second the just replacing the filter caps, all of the dead monitors I have found (admittedly much smaller monitors) have had bulging caps which simply needed replacing.
I had one friend with a larger lcd panel (about the size of yours) which had a bad self start circuit on the psu,which was due to a shorted zener diode, which in turn took out a bridge rectifier. If you aren't getting anything out of it I would try and trace down the startup 'bootstrap' circuitry and look for issues. If you are feeling really brave you can try just feeding voltage directly into the supply rail for the switching circuitry as well. Any luck locating a service manual? The aforementioned TV actually had a complete schematic of the power supply in it
my caps were bulging, with one shredded open at the top, and a dead short. which then shorted out a normal diode and scorched a zener, replacing them fixed all psu related issues.... i used several smaller caps in parallel to get the ESR down, its a miracle they all still fit in there.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
Yeah, someone on #hvcomm suggested something similar. The trick which sometimes works is to wind a 10 turn coil around the main SMPS transformer and connect this through a ballast capacitor (current limit) to a high wattage halogen supply of the SMPS variety.
This at least lets you get the thing going, so you can then find the shorted rail(s) and reduce the problem's complexity to manageable levels.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Flat panel TV repair
