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Component id needed

mcboon

Nov 22, 2023
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I am new here so if this needs to go in a different place please let me know. I am repairing an old VCR from the mid 80s and need help identifying the piece in the photo. It was on the main circuit board. I'm thinking it's a capacitor based on photos I've seen but do not see the capacitance. I am not an electronics expert. Any ideas? And where I can get one? Thank you!
tempImage45hMtF.jpg
 

kellys_eye

Jun 25, 2010
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The voltage rating (125VAC) indicates the device may be a VDR (voltage dependent resistor/ surge protector) whose value is nominally 4Mohms dropping to 2.5 ohms as it (rapidly) heats up.

Not seen one in this style before so maybe someone on here else is more familiar with it? A $20 component tester won't actually reveal this - it would just show it as a 'high resistance' or possibly 'OC'.
 

Delta Prime

Jul 29, 2020
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I would put that back!
There are sacrificial lambs. I usually see them get destroyed, kaboom! It looks pristine to me.
If it's a VCR from the 80s that's the least of your worries. Even right now you pull it out of the circuit the circuit should still work with or without it and they are normally used in parallel with the power rails not in series like a fuse or thermistor.
You can get them at digikey, Mouser, Newark element 14.
Looks like a (MOV)Metal Oxide Varistor.
You'll often see them call just Varistors.
The resistance is nonlinear and is dependent on a voltage applied to them.
They are for what is known as transient high voltage protection.
They will Absorb and conduct (clamping) this high voltage to a safe level but like I said I see them go kaboom or because they're for high voltage I say
VA-VOOM! Welcome to Maker Pro. :)
 
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mcboon

Nov 22, 2023
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Mystery solved! Thank you very much for the help and the excellent information. I will put it back in and pray for no kaboom!
 

73's de Edd

Aug 21, 2015
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No-no on varistor.
Looks like a paralleled ceramic capacitor and an anywhere from 2.5-4 meg resistor (being permissible) that would be from a circuit negative ground to chassis frame position. An ohmmeter and testing with one of its leads floating . . . . should confirm that resistance value..
You should have also given model and brand of Vee Cee Ruh and this parts circuit location for research..
 

Delta Prime

Jul 29, 2020
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No-no on varistor.
Looks like a paralleled ceramic capacitor and an anywhere from 2.5-4 meg resistor (being permissible) that would be from a circuit negative ground to chassis frame position. An ohmmeter and testing with one of its leads floating . . . . should confirm that resistance value..
You should have also given model and brand of Vee Cee Ruh and this parts circuit location for research..
That is a very interesting point!
Do you mean something like this?
photo_1700835089991.png
 

mcboon

Nov 22, 2023
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Thanks. Sorry I left out the info on the VCR. It is a JVC model #HR-VP70U. As for the circuit location, forgive my ignorance but I'm not sure what you mean. Here is a pic of where it was. You can see some discoloration by the 2 holes in the board and it's labeled CR901. This is in the back right corner of the VCR. Does that help at all?
tempImageeolJnX.jpg
 

kellys_eye

Jun 25, 2010
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The inclusion of a 'flash-over safety slot' in the pcb would indicate that the device is some form of transient protection.
 

mcboon

Nov 22, 2023
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Any more thoughts on this? Is this a ceramic capacitor as indicated by 73s de Edd?
 

kellys_eye

Jun 25, 2010
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One side of it is definitely connected to chassis ground (via the screw hole in the pcb) so it's certainly a transient suppressor. Such suppression can take the form of a capacitor and/or resistor to bleed voltages to ground (static).
 
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