Help! Pioneer T-6600 (R2R) Won't Go More Than a Second without the Tape Going Slack

[FabGadget]

I have a (so far as I am aware) previously-unused Pioneer T-6600 I just acquired that is having trouble keeping tape in the tape path, even after replacing all the belts. At first I could not get it to play/FF (it's an auto-reverse deck, so there's no rewind distinct from FF) at all for more than a second before the feeder reel starts spewing tape; and no matter which direction I had it playing/FFing, the uptake reel seemed like it was slower than the other reel. I put a drop of synthetic oil in the spindle shafts, the capstan shaft, and the pinch roller shaft as indicated in the manual. I did a lot of fiddling with the pads, and it seems like it's now consistently able to successfully play in the regular left-to-right direction with sound, but FF is only working occasionally without the tape slacking at the feed end. The reverse direction is still not able to play at all without immediately slacking.

Probably related to that, the left hub in particular seems to struggle the most to spin. At first it almost wouldn't spin at all, even without a reel. Without a reel, it's spinning now (mostly), but the lower pad that engages during playback is constantly making it spin rough and noisily, unless I manually disengage the pad, at which point the hub spins smooth and quiet (I can't tell if the right hub maybe is suffering from this as well, but it's not noticeable if it is). I find that the pad seems to be completely solid, which I doubt is supposed to be the case, to the point that I can't tell if it's rubber or dense felt that's somehow solidified with age. I can also feel the pad slightly sticking initially when I manually disengage it while the hub is stationary (though I'm not sure if it's the pad itself that's sticking or if it's the pad's arm as it rotates away from the hub).

All of that said, I hope it's not a situation where I'm fixating on the hubs/pads without that being the actual problem (or at least not the only problem), and what if it's not (or not just) that the uptake reel is too slow but that the capstan/pinch roller is too slow? I do notice the capstan flywheel is a little wobbly during playback/FF (though the capstan itself doesn't appear wobbly), and it has struggled with bumping into the speed-selector post, especially when the deck is horizontal. Anyone know how to get everything running smoothly?

 

[Nimbley]

Even being unused, these machines are highly mechanical beasts and will need extensive work. I'm not familiar with that particular deck, but I've rebuilt several machines, including a Pioneer. Setting the reel tension is a very important calibration and some machines have quite complex procedures to get it set right. Grease gets sticky after years of no use and will cause these tensions to change. Oil and running time may help, but ultimately it will probably need to be rebuilt. The motor run capacitors may have gone bad and the motor just runs out of power, the power supply in the unit may have drifted from specs... Cosmetically an unused machine is great, but one that has seen regular use over the last 50 or so years is probably going to be more likely to run properly without work even if worn out. You might try just letting the motors run without a tape for half a day or so, things might loosen up? You can use a rubber band to hold the capstan arm in place to keep the deck in play mode.

 

[Doghouse]

Even being unused, these machines are highly mechanical beasts and will need extensive work. I'm not familiar with that particular deck, but I've rebuilt several machines, including a Pioneer. Setting the reel tension is a very important calibration and some machines have quite complex procedures to get it set right. Grease gets sticky after years of no use and will cause these tensions to change. Oil and running time may help, but ultimately it will probably need to be rebuilt. The motor run capacitors may have gone bad and the motor just runs out of power, the power supply in the unit may have drifted from specs... Cosmetically an unused machine is great, but one that has seen regular use over the last 50 or so years is probably going to be more likely to run properly without work even if worn out. You might try just letting the motors run without a tape for half a day or so, things might loosen up? You can use a rubber band to hold the capstan arm in place to keep the deck in play mode.

Good advice. I'm a firm believer in "use, is the best form of preventative maintenance."

 

[FabGadget]

@Nimbley Thanks, that sounds like a good plan for the moment. I'll start it up when I get home and leave it running. As I mentioned, I did finally get it to play left-to-right, with no noticeable speed issues when I plugged in a pair of headphones, so I'm really hoping the motor and circuitry are fine (everything looked okay when I inspected the inner back end, though of course there's only so much to gather from a visual inspection) and it just needs to loosen up. It wouldn't even play at all at first, so hopefully the fact that it can play now is a good sign. In the meantime I'm all ears if anyone has some insight in replacing or restoring the pads (unless they're somehow supposed to feel completely solid).

 

[Nimbley]

The brake is usually a thin cloth or mesh over a rigid hub. They shouldn't give when pressed into. In fact some manufacturers specifically say not to touch the brake material or band with your bare fingers as the oils will contaminate them. There is a tension adjustment for them the same as the motors and capstan pull.

 

[FabGadget]

I didn't know that, but now I'm praising yesterday me for being thorough and wearing gloves, so thank you again! I'll see if I can find the tension adjustment for them as well when I take a look after work.