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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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VCR AIWA HV-MX1U, a bit strange...
Hi there,
this VCR will not operate properly. When switched on, the headdrum starts to rotate. When I try to load a tape, the cassette is ejected immediately. In the display, the label "DEW" ist lit. (rotating drum for faster drying?) But I can't find any dew-sensor in the drive-mechanism. The on/off button works, every other button is ignored. Is there any idea? 73 Peter |
#2
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I would not know physicaly where the dew sensor is in your machine, but
it is possible that it is defective. It is also possible that the electronics that it feeds may be defective. Jerry G. ====== |
#3
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Peter Lehmann wrote: Hi there, this VCR will not operate properly. When switched on, the headdrum starts to rotate. When I try to load a tape, the cassette is ejected immediately. In the display, the label "DEW" ist lit. (rotating drum for faster drying?) But I can't find any dew-sensor in the drive-mechanism. The on/off button works, every other button is ignored. if this unit is about 4-5 years old or more, and strange things happen, just replace the electrolytic caps in the power supply section. Some of these units are now starting to drop dead. -Ben |
#4
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The dew sensor is usually a small flat square about a quarter inch
square or smaller and about a sixteen of an inch thick with two pins or wires coming out of one edge that is sometimes mounted near the capstan or in that general area that monitors the level of humidity present inside the vcr. Maybe take the cover off and blow dry the carrage area for a few minutes and see if the dew light goes out. If it does then you are good to go, if it doesn't then you may have a problem in the circuit that monitors that sensor. |
#5
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Hi there, Thanks for reply. I think, this VCR has definetly no DEW-sensor. In the upper right corner of the drive-mechanism is a small PCB with two connectors. One is for the loading-motor, the second is marked DE and -empty- :-( Since I am working on VCRs for more than ten years, I know how a DEW-Sensor looks like and works, but naturally you know nothing about my skills. So I will check the PSU and wait for more ideas. Normally I would give up such a VCR (Longplay, but no HiFi-Sound), but it is a multinorm (PAL, NTSC, SECAM), so I should try to save it. 73 Peter |
#6
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Peter Lehmann wrote: Hi there, Thanks for reply. I think, this VCR has definetly no DEW-sensor. In the upper right corner of the drive-mechanism is a small PCB with two connectors. One is for the loading-motor, the second is marked DE and -empty- :-( Since I am working on VCRs for more than ten years, I know how a DEW-Sensor looks like and works, but naturally you know nothing about my skills. So I will check the PSU and wait for more ideas. Normally I would give up such a VCR (Longplay, but no HiFi-Sound), but it is a multinorm (PAL, NTSC, SECAM), so I should try to save it. 73 Peter Peter, Just thought of another thing you could look at. Yesterday I repaired a SABA vcr with similar symptoms: buttons ignored, power flashing on-off, unusual mode cycling, etc. Turned out that the front rewind switch was being pressed in permanently by part of the plastic front panel button, which had deformed. I discovered that when the front panel was removed the unit worked fine with but would go crazy when it was replaced. regards, Ben |
#7
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Hi Ben,
the news: Came into the workshop this morning and plugged the VCR into mains. VCR came up immediately and worked fine. I think, I should not understand this yet. Life is too short ;-) At this time I assume static charge at the DEW input of the control-processor. I have no schematic to verify this. In my last post I had an error. The unused connector is marked 'DW'. Seems to be for an DEW sensor. Let's hope the VCR will work the next days so I can return it to the customer. 73 Peter ps.: In the past I also had stuck buttons. This failure also occured when front panel removed. |
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