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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. |
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#1
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APEX PF2720 MAKES WEIRD NOISE
Can anyone help or offer some direction?
My Apex TV was working fine until today. When I turn it on there is a strange whining sound and no picture. Anyone had an experience with this? Thanks, Gary |
#3
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APEX PF2720 MAKES WEIRD NOISE
wrote:
Can anyone help or offer some direction? My Apex TV was working fine until today. When I turn it on there is a strange whining sound and no picture. Anyone had an experience with this? ** So there is normal sound from the speakers ? If so, the set many just need a good clean around the picture tube and any wiring going to and from same. I have used rags moistened with denatured alcohol to get all the black soot and dust off, plus a vacuum cleaner if it is really bad. It's probably an outside chance, but what have you got to lose ? FYI: UNPLUG THE SET AND LEAVE IT FOR 10 MINUTES BEFORE DOING ANY CLEANING. ...... Phil |
#4
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APEX PF2720 MAKES WEIRD NOISE
On Thu, 15 Jun 2017 18:20:41 -0700 (PDT),
wrote: Can anyone help or offer some direction? My Apex TV was working fine until today. When I turn it on there is a strange whining sound and no picture. Anyone had an experience with this? Thanks, Gary Another guess is a shorted horizontal output transistor and the whine is a switched power supply trying to drive a dead short. In any case not worth fixing. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#5
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APEX PF2720 MAKES WEIRD NOISE
On Friday, June 16, 2017 at 4:28:08 AM UTC-4, Phil Allison wrote:
wrote: Can anyone help or offer some direction? My Apex TV was working fine until today. When I turn it on there is a strange whining sound and no picture. Anyone had an experience with this? ** So there is normal sound from the speakers ? If so, the set many just need a good clean around the picture tube and any wiring going to and from same. Cleaning in and around the second anode assy won't help a no picture condition and whine, which is what OP complained about. FYI: UNPLUG THE SET AND LEAVE IT FOR 10 MINUTES BEFORE DOING ANY CLEANING. ..... Phil Good advice, assuming his TV's HV transformer has an internal bleeder. If it doesn't contain an internal bleeder, the CRT may store 20KV for several days at the very least and will deliver nice jolt to whoever tries to wipe down around the second anode cup, even days later. Some TVs mute the video first before the HV is shut down, and the charge on the CRT remains very high with no bleeder. It would have been nice if OP had told us if it's a CRT, plasma, or LCD. The only thing they all have in common is that produce a picture. |
#6
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APEX PF2720 MAKES WEIRD NOISE
On Thursday, June 15, 2017 at 9:20:46 PM UTC-4, wrote:
When I turn it on there is a strange whining sound and no picture. Anyone had an experience with this? Thanks, Gary Is the sun shining where you are? Knowing the weather is as about as helpful as the information that you posted. Start with model number. Absent that, whats the technology? CRT, Plasma, or LCD/LED? Whining complaints along with a change of performance are *usually* a switch mode supply under a higher than designed for load. |
#7
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APEX PF2720 MAKES WEIRD NOISE
On Friday, June 16, 2017 at 9:57:32 AM UTC-4, John-Del wrote:
On Thursday, June 15, 2017 at 9:20:46 PM UTC-4, wrote: When I turn it on there is a strange whining sound and no picture. Anyone had an experience with this? Thanks, Gary Is the sun shining where you are? Knowing the weather is as about as helpful as the information that you posted. Start with model number. Absent that, whats the technology? CRT, Plasma, or LCD/LED? Whining complaints along with a change of performance are *usually* a switch mode supply under a higher than designed for load. Oops, see the model in the title.. If you have a DMM, check the LOP/Horizontal output transistor for a Collector to Emitter short. That's the easiest check to make. Other than that, any kind of shorted device on the secondary of the smps will cause a whine from the supply. |
#8
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APEX PF2720 MAKES WEIRD NOISE
On Thursday, June 15, 2017 at 9:20:46 PM UTC-4, wrote:
Can anyone help or offer some direction? My Apex TV was working fine until today. When I turn it on there is a strange whining sound and no picture. Anyone had an experience with this? Thanks, Gary Thanks to everyone for taking the time to respond. Jeff, The images from the link you supplied were awesome. I think it's time for me to help the economy and buy a new TV. |
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