My JVC HR-S7800U VCR stops after 3 seconds and the drum head doesn’t spin

[videoconverter11]

I have a JVC HR-S7800U. When I insert a tape, it begins to play, but after about three seconds it stops and displays “Auto” on the screen. I’ve attached a video showing the issue. The drum also doesn’t spin, and I’ve noticed that it seemed unusual is the wheel connected to the motor belt — it moves back and forth quite a bit. Are there any general diagnostics I can make based on this? Thanks

Link: https://youtu.be/-k-2tgMdPn8?feature=shared

[themaster1]

Have you tried other tapes ? Before doing anything try other tapes just to make sure

These JVC's they don't like sunlight/ lamp , just put something to cover the light sensors (right and left)

You could check the belt below the mech, ensure it's not too loose /mushy, you'd need a brand new one if that's the case.

[aramkolt]

I think the key here is that the drum doesn't spin, that is fairly rare unless the drum itself is disconnected which would be the small ribbon cable that goes into that top circuit board.

Does the drum do a slight spin or move at when you initially plug in the VCR?

[themaster1]

Can be the 9V on the power supply (if drum really does not turn) but for now i doubt it

[dellsam34]

Check the CP protection circuits, they are usually on the right side of the mechanism next to the power supply, I can't remember which one specifically powers up the drum motor but they are easy to test, check for voltage on both legs, if one doesn't read a voltage it's blown, You need the schematic to find them.

[davexnet]

Check the CP protection circuits, they are usually on the right side of the mechanism next to the power supply, I can't remember which one specifically powers up the drum motor but they are easy to test, check for voltage on both legs, if one doesn't read a voltage it's blown, You need the schematic to find them.

This blew in my jvc many years ago. Fixed under warranty. The ticket mentioned the protection circuit,;
I had similar symptom, drum not spinning. Never did find out where it actually was

[Tester.]

I too had this fault on three of my JVCs, years apart.

[videoconverter11]

Have you tried other tapes ? Before doing anything try other tapes just to make sure

These JVC's they don't like sunlight/ lamp , just put something to cover the light sensors (right and left)

You could check the belt below the mech, ensure it's not too loose /mushy, you'd need a brand new one if that's the case.

Thanks, I have tried other tapes and it has the same issue. I also covered the sensors with the same result.

Can I ask where the belt is located? thanks!

[videoconverter11]

I think the key here is that the drum doesn't spin, that is fairly rare unless the drum itself is disconnected which would be the small ribbon cable that goes into that top circuit board.

Does the drum do a slight spin or move at when you initially plug in the VCR?

It doesn't move at all unfortunately.

[themaster1]

Have you tried other tapes ? Before doing anything try other tapes just to make sure

These JVC's they don't like sunlight/ lamp , just put something to cover the light sensors (right and left)

You could check the belt below the mech, ensure it's not too loose /mushy, you'd need a brand new one if that's the case.

Thanks, I have tried other tapes and it has the same issue. I also covered the sensors with the same result.

Can I ask where the belt is located? thanks!

The drum should be rotating, so it's a power supply issue, like others said, check the circuit protector (CP) on the secondary, i think there is another outside the power supply (left side of the board). The CP's protect against over voltage, they just short.

[davexnet]

Have you tried other tapes ? Before doing anything try other tapes just to make sure

These JVC's they don't like sunlight/ lamp , just put something to cover the light sensors (right and left)

You could check the belt below the mech, ensure it's not too loose /mushy, you'd need a brand new one if that's the case.

Thanks, I have tried other tapes and it has the same issue. I also covered the sensors with the same result.

Can I ask where the belt is located? thanks!

The drum should be rotating, so it's a power supply issue, like others said, check the circuit protector (CP) on the secondary, i think there is another outside the power supply (left side of the board). The CP's protect against over voltage, they just short.

I've not been able to find any further info. What do they look like? Do you have a picture of one?

[themaster1]

[QUOTE=davexnet;2780736]

[I've not been able to find any further info. What do they look like? Do you have a picture of one?

See attached picture. There should be a writing close to it like "CP5301" etc..on the board.
There are at least two CP's like i said (most likely more) one in the secondary of the PSU and the other close to the PSU.

[Tester.]

The relevant CP tends to be kind of near the drum (usually to its right), oftentimes marked as "CP4001". The approx. location and designation are consistent on the (several) JVC models I know.