I'd would like to swap the old drum with another JVC drum sadly the pinout don't match, the new one is only 4 heads.
Models are hr-s8600ms and hr-s7600ms.
I just don't know if i can do it and the right way to populate the socket.
If someone has tried this before please let me know
I would not attempt it unless you are sure the pin out is correct, Even then, it may not work correctly, who knows how the system control reacts when it sees open circuit on the flying erase head rotary transformer pins.
I've looked at the service manuals pretty extensively on USA models, basically all JVCs have the flying erase head as the last 2 pins and the rest of the pins stay in the same order for all of the 7x00, 9x00, 3x00, 4x00, series at a minimum. While I haven't actually done it, as long as the pins are set all the way to the side of the "1" numbered pin, it should work as long as the pin pitch (width/spacing) is the same, which they should be. I assume a signal only gets sent to the flying erase head when erasing a tape. I think I've assembled a JVC before without connecting the head ribbon at all (just forgot) and it still moved the tape as though it was playing, there was just no video output/hifi unsurprisingly.
Good to know, this comes in handy when swapping normal heads for DD ones. I would still use the same type of head just to make sure the ribbon cable won't shift and shorts out something.
all JVCs have the flying erase head as the last 2 pins and the rest of the pins stay in the same order as long as the pins are set all the way to the side of the "1" numbered pin, it should work as long as the pin pitch (width/spacing) is the same.
Thing is on the service manual we can only guess which is the 1st, they only show on the chipset side not the socket.
If i had to guess and looking at the cable (8 pins, followed by 3 others with an opposite angle) , the 1st is on the right side (looking at the socket from above/normal). I could be wrong though
edit:
unless it's the opposite, left side first pin (see 2nd picture), thanks for confirmation. Always have a hard time understanding these diagrams
Last edited by themaster1; 02-06-2025 at 02:32 AM.
Well today i tried so i did connect on the right side of the socket without luck. The vcr did boot and immediately shut off.
Both drums have 8 pins + 5 (with a ° angle) for the Original (with Flying E.head) and 3 pins (with a ° angle) for the 4 heads.
Dead stuck for now
Edit:
Now that think about it, it could be the dynamic drum that's dead (i've spotted a few light cracks), I'll try with another non DD drum soon
Last edited by themaster1; 02-07-2025 at 01:29 PM.
So do you know for sure that your DD unit is working and is it still connected to the motherboard? Usually non-DD drums do not have the mounting screw holes on the bottom of the drum, so unless you have it kind of floating in the socket not attached to the drum or have an extension cable on it, my guess is it's the lack of a functioning DD that is causing the shutdown.
typically you'll know that the DD is working if you hear the DD motor move forward and back at initial power-on.
No luck with the other drum (non DD) , same song boot+ auto shutdown
You can't put a non DD drum on a DD VCR unless you disable it electronically or have a working DD drum gear box connected with an extension cable to the motherboard. There is a guy who sells a DD emulator now for $90 over at vhelp.
If the DD system causes a CP (circuit protection fuse) to blow you'll need to replace it first.
