Ed in Tx, is you out there?

[Barry777]

Hi Ed,

All my JVC's are working fine now, but I do have one rather silly question. My machines (BR-S822U, 500U and 800U) have very similar mechanisms and appear to be "older" versions according to my service manuals. Thankfully, the alignment procedures weren't much affected. All my machines lack the tension sensor (the one that looks a little like a full erase head), which was my first clue that the machine doesn't exactly match the manual. I was pulling the reel motor assembly to replace the worn brake pads with small pieces of leather, which was a great way to earn some brownie points since I took the wife to the craft store for the leather!

My question is about this weird little sprocket-looking wheel on the underside of the mechanism right by the takeup reel motor. It's part of the chassis-mount stuff and you have to be careful to work the reel motor assembly back under it during reassembly, without disturbing its position. I remember seeing this sprocket somewhere in the manual but can't seem to find it, now that I want to learn about it. I think I remember it having something to do with tension. Would you happen to know what this is? It can be turned from above, but that requires a special tool I don't have - smaller in diameter and with finer "teeth" than the standard one. Of course, I'll have to pull the mechanism if I ever need to adjust it - thankfully I don't seem to have any trouble with it right now.

The sprocket itself is maybe just over 1/2 inch in diamater, with very fine teeth. Looks like stainless steel, very bright and silver. Thanks in advance for your help! As a side note, I got some weird performance when I put it back together; the FF function actually slowed way down when it was supposed to really start cooking. Also, the tension arm would slam violently back and forth when I loaded my JVC torque meter tape. Turns out the back tension was more than 70 grams as opposed to the spec of 54. A quick tension bias adjustment fixed that. I'm learning! These pro machines are a different animal altogether.

It's monsoon season here in Arizona, and the house is at 50 % humidity, even with the A/C running constantly. I thought I'd better pull all my capstans to lubricate the bearings to keep the moisture out and prevent rust forming in them. This is what started this little career underneath the mechanism. I have my Alesis BRC on the way, so it was time to start tip-topping these machines for the long haul. Thanks again Ed ~~~

Barry