Teac A-1250S AUTO-REVERSE PROBLEMS!!

[sean sweeney]

I work at a music store working on and repairing old decks and whatever comes through the door. It's a very wide scope that I work on... I've restored several reel to reels since I've been here and this unit has been vexing me for over a week.

It won't go into auto reverse and also will not rewind!
It plays fine in forward mode, and will fast forward.

I have replaced all of the caps... I've checked all of the relays... they all seem to be good, or at least free moving. When I attempt to rewind or engage reverse play the capstan direction will change as long as I hold down the reverse play button but the pinch roller won't engage and when I let go the capstan will spin in the opposite direction. The reverse tension arm that has the terminals for the auto-reverse can be shorted, which I've done, and the relay will repeatedly click, but no actual reversing will happen other than momentary reversal of the capstan once again. It also will not rewind. I'm a little befuddled at the moment and perhaps need some help from more superior minds, as I'm about to give up on this and I hate to do that when it's a nice sounding deck and would be an asset to the store (and my job). I really want to get this thing going again! It's in perpetual state of disassembly and I want to get it out there. Can anyone help me with some possibilities of where the problem lies, I've checked pretty thoroughly for bad solder joints... I'm about to try that again. I know sometimes you may get a real lemon, but I've had a nearly 100% success rate with machines of all styles that I've had in here... this one has got me stumped!

 

[sean sweeney]

OK! Well... no one replied to me, so I downloaded the maintenance manual... and it mentioned diodes... so I tested and preemptively changed the two diodes they were talking about that the problem of "no reverse function" and "no rewind" had in common. NO CHANGE!

So then I stared at it for about an hour.

And then I came back to the manual and recognized the other things the two functions had in common, which was the relays. I had tested them and found that none of them were bound up and seemed to be ok... and I had a look at relay 3 and four and after running them through the paces they seemed to be doing their respective jobs... I then focused on RELAY NUMBER ONE!

I wasn't ready to commit to removing (very hard ) and replacing it preemptively, so I took my soldering iron and burned a hole in the side by the contacts and used a ceramic screw driver to actuate the relay... and BAM... the functions came to life...

so then I had to face the doom-laden option of replacing this very hard to get at relay. My solder-sucker was clogged, but after removing the relay from my parts deck, I realized that it was far too tight in this operation to even use the old solder sucker... I tried to clean it and effectively destroyed it and in a temper tantrum threw the whole mess away... couldn't find any solder wick ANYWHERE locally... so I took some fine stranded speaker wire that I had here and soaked it thoroughly with solder flux and went at it carefully removing each pin of solder with the makeshift solder wick. I don't think any store bought wick would have worked better... the flux laden speaker wire sucked it up like a thirsty hydra... and the defective relay came out like a bad tooth.... and the new one went in like clockwork in about a tenth of the time... I eagerly powered the deck up and the reverse and rewind functions came to life... by this time, it felt like high magic had been done. I had replaced all the caps, both electrolytic and the motor run caps as well... and also some of the diodes... stared and cursed for hours... but really only about two days of hard work. This was the worst deck of them all... but I didn't give up. I've belted and capped many decks in this store... this was the worst. But it's nice to have it back on line. Just to reference this problem and the eventual solution... RELAY NUMBER ONE or the operation/run relay was the major malfunction. RELAY NUMBER ONE. Please take note.
Thanks and hope this helps someone later on!