About Henry A. McKelvey Expertise I have worked in the Electronics field for 25 years, and have been a Telecommunications Expert for 20 years. My Expertise has been in: Video, Audio, RF, Television, and Stereo. I have been in the Television repair business for 25 years and have repaired over 20,000 Televisions in that time. I was a manager of an Information Technology Training Team at The Verizon Advanced Services Group Center, and a Distinguished Member of Technical Staff at Verizon Laboratories. I am now working full time in the TV repair industry until I can find another full time job, I know what your question is: "why don't you just work full time in the TV repair industry permanently?" Well the answer to that is simple, due to the complexity and the DIY craze, TV repair work is at best a good way to make extra money, not to rely on it for your livelihood. A sad truth, but a truth nonetheless.
Experience 25 years as an Electronics Repair Technician, 20 years as a Telecommunications Expert, and I love Electronics.
Organizations The Society of Broadcast Engineers (SBE)
The International Society of Certified Electronics Technicians (ISCET)
Publications On-Line: http://www.fixya.com/users/shuttle83 (solutions to repair issues)
US Patent and Trade Office: (Copy and paste the link below)
http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=0&f=S&l=50&TERM1=McKelvey&FIELD1=&co1=AND&TERM2=Verizon&FIELD2=&d=PG01
Education/Credentials University of Phoenix (MSCIS working on)
University of Phoenix (BSIT 2006)
World College CIE (BTEE 2006)
Cleveland Institute of Technology (ASEE 2006)
National Education Center (Diploma in Commputer and Network Technology 1989)
TESST Electronics School (Diploma in Electronics Engineering Technology 1985)
AG Bell Vocational High School (Diploma in Electronics Repair (Radio and Television Repair 1983)
Awards and Honors Society of Broadcast Engineers Membership (July 2006)
Special Technology Achievement & Recognition Award (STAR Award) August 2004 (ISO 9000 Certification VTO-SIT)
CWNP Certified Wireless Network Administrator (June 2004)
Special Technology Achievement & Recognition Award (STAR Award) September 2003 (MSN Project)
Special Technology Achievement & Recognition Award (STAR Award) November 2003 (Client CD and Registration Server Issue)
Network Management Certification (ICCP)(2002)
Data Communications Engineer Certification (Global Knowledge)(2002)
TCP/IP Network Analyst Certification (ICCP) (2002)
Winners Circle Award for Development of the DNOC Provisional training Team (2001)
FCC License General Radiotelephone without endorsement (1985)
FCC License General Radiotelephone with shipboard RADAR endorsement (1985)
Certified Electronics Technician Certificate (Electronic Communications)(1989)
Certified Electronics Technician Certificate (Consumer Electronics)(1985)
6 Patent Applications on file (do google search on "Henry A. McKelvey")
Past/Present Clients See http://www.fixya.com/users/shuttle83
http://www.google.com/search?hl=en&rlz=1T4DMUS_enUS243US243&q=%22Henry+A.+McKelvey%22+TV+Repair&aq=f&oq=&aqi=
Question QUESTION: It's an oldie 45" but when I bought it 19 years ago, eight months into ownership the picture went dark. I pulled out the chassis and checked the solder joints on the power supply and found the flyback pins were cold-soldered and cracked. I re-soldered, checked the whole set for the same trouble and re-assembled. That worked, and it has since been playing beautifully until last month when the picture went black again. I performed the same procedure as before but didn't find any bad joints this time, instead, I determined the flyback had burnt out. I decided to replace the whole power supply and doing so brought it back to life with a beautiful picture for that evening. Next evening however, it turned on, but there was no bright, vivid picture. The RGB Screens do light up though and if I turn up the drive pots they each brighten and form the typical pale white raster. But I have to really look close, and in the dark, to make out the faint video cable transmission. All the colors appear to be there and superimposed correctly, only the video image is very washed out and hardly visible. My onscreen menu for adjustments work seemingly as normal giving the impression that there is high voltage putting it there. I decided though that the new PSU burnt out again lacking horizontal drive, so I had Pioneer send me another one. NOT the problem. I'm at a loss now wondering what it could be. Any tip would be appreciated.
ANSWER: Hello Ray,
First of all reset those drive pots back to their old settings and get the schematic for this TV. Then using the schematic and a signal generator set to the levels on the schematic adjust those drive pots back to the proper bias values.
At this point we re ready to tackle the real problem, which is most likely a lack of high voltage or the filament voltage is not high enough,not to mention the possibility that the CRTs might be malfunctioning.
OK let's tackle this in a methodical fashion.
1) using the schematic as you guide and setting the video signal generator to the setting on the schematic.
2) Check the voltage of the filaments of the CRT and determine if they are at the proper level, if not this could be the issue. If they are ok check the high voltage level at the CRTs and at the High Voltage trippler. if the voltage is not at the proper level this could mean that the flyback, the high voltage trippler, the horizontal output transistor,or any of the associated circuits have malfunctioned
3) if the high voltage is OK and the filament voltage is ok this may mean that the CRTs are defective and are malfunctioning. For this I suggest the use of a CRT analyzer to test the CRTs. Taking into mind that CRTs are tubes, the CRTs analyzer is just a tube tester for the CRT.
4) following the instructions on the CRT analyzer test each of the Tubes and determine what the problem could be.
QUESTION: Thank you sir for the speedy reply. What you advise makes all the sense in the world. I am not a technician but above average to electronics. I ordered another PSU to avoid buying the high voltage probe and the CRT analyzer. I didn't get results with a second board. I believe there is high voltage present but I can't measure it. All other lower voltages are present as follows: 6.25v, 9v, 12v, 13.5v, +23v, -23v, 30v, 35v, and 39v these coming from the PSU stepdown to the measurement exactly. My CRT filaments can be seen glowing in the neck and receive power from here. I failed to mention before that on the convergence board there are six 5 or 10 watt power resistors next to the STK4277 chip. When the set is running 4 of these resistors are so hot I can't touch them for a second or get burnt. The other 2 are not even warm. I checked them and they are all to the correct value. Is this a hint that maybe the STK blew? From what I've read, when it does you lose convergence but I haven't lost convergence there's only the weak video signal path to the tubes. Here in Hawaii there are no tv repair resources so I'm trying to make a go of it as best I can. By the way, a full blown schematic doesn,t exist anymore and the service manual I have isn't helpful at all.
Answer Hello Ray,
I think you may have hit upon something here. The resistors connect to the convergence amplifiers right? What I need for you to do is to measure the VCC + voltage of the STK4277s, then I want you to remove the STK4277s and then try to power on the TV set. The set should come on (sound at least). The convergence amps might be the problem, they could be dragging down the power supply and causing system failure. This has happened before with the use of STK convergence amplifiers.
You may have a convergence problem but the amps might be dragging down the power supplied to the video section thus masking the problem
