85-16b develops its first problem since I bought it new 23 years agp

B

BRDTS

Member
This actually started some time back so I moved to using other Tascam machines I have when needed. Thought some of you transport gurus may have an opinion on this before I haul this over to Montebello.

Reel motors have decided to not move tape .. at all ...in play/ff/rew or spool. Whether tape is loaded or not, capstan runs all the time .. which normally it wouldn't unless tape is across the red optical light in the path.

So those are two weird things at the same time.

I cleaned the optical area a few times and that doesn't seem to be the problem, although the capstan continues to spin even with no tape loaded.

So basically, no reel movement. I can load tape, hit "play", pinch roller engages, and basically the capstan will pull tape and spill it.

I have some card choices there in the back that I suspect may be the culprits, including possibly the tension servo amp card or capstan servo amp card. But this gets into areas, I'm not really in to. I pulled several of those cards for the very first time today and other than 23 years of dust, nothing seems blown or burnt out on them ... not that they would.

I've been eyeing another couple of 8516bs out there to have an extra and for parts and cards to swap out. Or, maybe I'll just take this over to Montebello and dump it in their laps. Or maybe this will just be the end of my 8516 era.

Any off-the-top-of-your-head tips on what to check regarding the transport cards?

By the way, looks like someone posted a partial 8516b manual pdf if you feel like some boring reading. Although schematics aren't there as those are another additional couple of hundred pages.
http://scc-344-recording-arts-fall-2009.wikispaces.com/file/view/Tascam+16-85B+March+2008.pdf
 
I can't tell you either but it wouldn't hurt to check the power supply for any bad fuses and then pull any cards controlling the transport, clean their contacts, and reinstall them. Just make certain the power is off before doing anything.
 
Thanks for the tip. One of the 20a fuses was bad. A quick trip to radio shack and transport's moving great so far in all modes. Dunno why I put this off for four years.

Looks like one of the fuse holders is bad too, so I'll have to fix that and then just run the machine for a week or two to see if anything crops up.
 
After this many years you should consider re-capping the power supply.

Also suggest you connect your equipment to a good surge protector such as Panamax.
 
Transport is still a-okay with the fifty cent radio shack fuse replacment. The optical shutoff is still a little weird.

Normally, the red optical light only allows transport movement and capstan spin if tape is loaded, blocking the optical path to a mirror (I guess it's a mirror in there).

Instead, the capstan spins all the time, even with no tape loaded. Which is no big deal by itself I guess. But additionally, if I ff or rew tape all the way off onto the supply or takeup reel, the motors and tape keep spinning until I manually click the stop button on the machine or aq85 remote. Meaning, the optical isn't doing its job.

One thing I did accidently find out is that if I shine a flash light at the optical area, that works great to also stop the reels and capstan when tape runs all the way off a reel. Clicks the machine right into stop. So, I can send a reel of tape into ff, let it run all the way off onto the other reel ... and then, standing a foot or so away from the 8516, aim my flashlight at the optical area which stops everything, well, except the capstan starts spinning again when I turn off the flashlight ... hahah. A flashlight remote stop.

Any ideas on that? I've cleaned the optical area about six times now and all I can think of is that something is not quite lined up in there somewhere with the optical light and mirror.

By the way, I'm having some fun this week with this. The tape machines spend most of their time covered up with no use. It's kinda nice to crack open the 8516 for a change.
 
Well it stands to reason that either something is misaligned between the lamp and sensor, or the lamp isn't getting enough voltage and therefore it is not bright enough. I'd be messing with that. It sounds as though, really, everything functions, you just have two elements there that aren't talking to each other. The other thing you could try is if you can take the faceplate of the front of the transport and see where the sensor plugs in and exercise that connection. Maybe there is oxidation in there that finally got to the point where it was too much and there is enough resistance in that connection to reduce the voltage transferred from the sensor.

By the way, I'm having some fun this week with this. The tape machines spend most of their time covered up with no use. It's kinda nice to crack open the 8516 for a change.
Click to expand...

Wow...I totally know what you mean. I'm just a hobbyist so I'm not in the studio much anyway and particularly for the past couple years since I've been focused in refurbishing devices and we've had a ton of stuff happening at home and work, but this last couple of months I've hardly spent ANY time in there...3,400 mile road trip with travel trailer in tow with my family through Yellowstone, Mt. Rushmore, etc., working on completing exterior of our house from last year's remodel and so on, but I was in there just the other night to document some differences between my Ampex MM-1000 relay box as compared to the schematic. I was mentally whining about going into the studio which is a TOTAL mess and having to climb behind the machine just to get a small bit of info so I can try and put to bed why the thing won't lock into PLAY mode, but I really do enjoy that big beast...flipped the gate down on one of the headblocks, had to unplug a relay to study the contact numbering...the sight and smell of dormant "big-iron" just waiting to be up and running. There is something stirring about a tape machine to those of us that like them, and frankly I believe that for those that USED to use them and don't anymore in the name of progress, I betcha most would admit after rolling a reel of tape that they too miss the experience.
 
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