AG-1980 refurbished, now HiFi and EP unstable?
 

I have several Panasonic AG-1980 refurbished VCRs. One of them which has been working fine has developed two problems. It has trouble locking into a hi-fi audio track and will switch between normal and hi-fi. And it no longer plays EP speed tapes stably, which it used to do wonderfully. Are these problems that can be solved with some sort of adjustment, or is it likely a more serious problem like the heads are worn out? Incidentally, turning off the TBC makes the stability problem worse.

Before you start messing with the alignment examine the heads with a macro lens and make sure the heads are not chipped or have oxide buildup around them.

As to the head wear, There is a tool but pretty hard to find to measure the head protrusion from the drum surface which determines how much wear before the drum assembly needs to be replaced, unfortunately you will not have access to such tool.

If you have access to an oscilloscope and a good prerecorded tape you can tweak the alignment but it is not going to be as perfect as a factory alignment tape.

When TBC on/off makes matters worse, it's almost always a caps issue.

This VCR is a beast to repair, even I don't attempt it.

Send it to TGrant, pony/suck up the ~$400 for the work, and know it will get the best repair possible. He'll examine everything from heads to caps, scoping things as needed. He has the tools and knowledge. I'm all for DIY, but this deck will be extremely difficult, like 10 on a scale where 1=easy/10=hard.

Great VCR, worth it.

Consider a JVC as primary, keep Panasonic wear to a minimum for tapes that really need it.