#31
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That's what I thought. There's a number on the bridge rectifier, I think I might have something in my parts stash that might work, (I had found a couple of baskets at the local SA a couple of years ago that were full of NOS TV and VCR parts like IC chips, capacitors, resistors, diodes, fuses, rectifiers, rectifier bridges etc. that came from a local appliance store that went out of business.)
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#32
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The Bridge Rectifier in my VCR that was bad is a S1WB S40 Rectifier Bridge, at least that's the numbers on the top of the rectifier bridge which when I look that number up on google, nothing shows up...
See picture below. |
#33
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40 71 could be just a date code for 40th week of 1971, if that fits the date of manufacture of the VCR.
Edit: although that seems very early. |
#34
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That seems a bit too early for a date code, unless Panasonic was using up old parts when making their VCRs, because this VCR is from 1987...
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#35
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Yeah, on second thought, not likely.
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Audiokarma |
#36
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Quote:
https://www.mouser.com/datasheet/2/3...BA-1202965.pdf Perhaps the 40 indicates 400 volt? just a WAG, jr |
#37
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Quote:
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#38
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UPDATE: Replaced the bridge rectifier and the VCR is still blowing fuses, so I wonder if maybe the Q1 is bad in the power supply board (the transistor on the heatsink.) when I did the diode test it seemed like it checked fine, but maybe I wasn't doing the check correctly.
What would the correct replacement for that transistor be? I looked up that transistor (it was a Panasonic part number) and it didn't seem to cross-reference to anything currently being made (no NTE parts or anything.) |
#39
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If its anything like my unit, the heatsink transistor was bad after the fuse kept blowing. my mistake was not using a dim bulb tester the first time around, so I had to buy the replacement transistor TWICE. Luckily there was some NOS on ebay.
Yours has no C or B value on it? |
#40
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Quote:
I'll take a look in the morning. |
Audiokarma |
#41
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Hello. That looks like a rebadged Panasonic PV-4750. The 4760 is the hi-fi stereo version. Be sure to check the electrolytic caps in the power supply before using the machine.
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#42
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If this is the power supply your machine has, I can post the full schematic if you need it.
Fivos |
#43
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yep that's it right there, I still need to check the switching transistor in the power supply (Q1) because this power supply only has 2 transistors in it overall and the one of them is the Switching Transistor (the transistor attached to the heatsink) that's the only part I haven't changed yet that I suspect might be still causing the VCR to blow fuses.
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#44
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Quote:
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#45
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Yes, all the diodes checked fine yet. The only diodes that checked bad was the bridge rectifier, which I already changed that out for a modern replacement the switching transistor I have not had a chance to check yet, the way they did the power supply in this VCR is that you have to disconnect a ribbon cable that's connected in a strange manner and then undo 2 solder blobs holding it to the main circuit board and then bend a retaining tab and then gently remove it from the main board without cracking the main board.
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Audiokarma |
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