Four-track problems (sticky shed?)

[masonpitzel]

(originally posted in Gear Talk because I'm a dumbass)

So I just started playing around with the Teac A-3440 my band purchased the other day, and there's definitely something wrong with it but I have no idea what.

Here's what goes down:
- Play. Tape starts playing back extremely fast -- just marginally slower than FF. Freq response is limited as well. It sounds mainly a lot like listening to a fast-fowarding tape on repro. (Regardless of whether I put it on 7.5 or 15 ips, this happens.)
- Reverse, to slow the tape before stopping. While it's reversing the sound gets clearer and louder. You know what a reversing tape sounds like; this sounds like that. (This is the part where I get a little excited because things seem like they're working how they should). Stop.
- Play. Tape seizes up immediately. From here I can FF or reverse, and hear things on repro through the headphones in the meantime, but I can't play the tape. Whenever I hit Play, the machine just instantly goes "chnk" and stops.

I think I've eliminated sticky shed as a cause, as I cleaned the heads and tried two different reels that I know to be shed-free, and the same thing happened. On top of that, I can play the tape pretty much all the way through if I don't stop and re-start -- it just plays retardedly fast, like 50 ips or something. If I stop and re-start, it'll seize, and won't play again til I put a different reel on.

Anyone have any ideas?

Addendum: Okay, so now it won't play at all. Just ff and rev. Definitely thinking the path is all gummed up from sticky shed. Can anyone confirm?

[The Scum]

If it's gummed up from sticky shed, there will be brown oxide schmutz all over the tape path...on the heads, rollers, guides...everywhere, and in little piles around the guides and stuff...and you'll have to scrub pretty studiously to get it off.

It sounds like you might have tension problems, or perhaps a motor or servo that isn't functional. There's usually a tensioning procedure in the manual...usually play a tape, watch where the tension arms are, and adjust a trimpot.

When it seizes, can you manually turn the reels to add slack to the tape, then tighten them back, and make it go?

[Judas Jetski]

I've had a number of older decks which did similar things. It was often related to the pinch roller not engaging properly (or at all). In every case, it's been because of dried or hardened grease which was interfering with the action of the mechanism which moves the pinch roller. I strongly suspect that this is what's happening with your deck.

One of these decks is a TEAC 40-4, which I believe to be the pro version of the 3440. On that deck, the pinch roller and lifter mechanisms are controlled by a plunger solenoid which is packed with grease. I opened the deck up, figured out which part did what, zapped it with a little lithium grease, worked the mechanism back and forth about 600 times (by hand and using the switches). Problem solved.

Here's the thread, which is almost exclusively me talking to myself:

http://messageboard.tapeop.com/viewtopi ... t=teac+404