Rowe TI-1 selector coil stuck on

LyonsArcade

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Hi guys;
I've got a Rowe TI-1 with the familiar Model #1100 carriage in it... the problem I'm having is, when I select a song, every few songs the selector coil locks on, in the write-in. So the buttons will stay stuck in, the selector wiper will spin around, the coil will fire to lock the pin down, then stay stuck on... so the read out will find the record, and play it over and over again since the reset coil can't push the pin down, since the selector coil is holding it down!

So the coil starts smoking after a couple minutes and you realize it's stuck in. Usually the buttons are stuck in too. If you turn the scan switch to off, the coil immediately releases, and when you turn the scan switch back on the coil is fine. So I don't believe it's the actual coil, it's whatever fires it.

I've looked over the schematics but can't figure it out, what makes that coil fire, and what kills the power to it? Does it involve the latch relay, since the buttons are sticking in? It doesn't do it every song, just every few.

Thanks!
 
Hello,

Sorry I do not know your name.

I would make a paper taper out of writing/copy paper and pull this through the open contacts on the on relays S1 & S2 on the search unit to clean the contacts (do not use any form of switch or contact spay). It may be as well to do the same to the open relays on the back of the keyboard (these are under a plastic cover).

Regards
Alan Hood
ami-man
UK
 
Thank you Alan, I know the two relays you're talking about on the Search unit, one of them wass misadjusted before, I'll check those out and also the ones on the keyboard. Thank you for your help!

Ron
 
Alan, I checked adjusted and cleaned the S1 and S2 relays, and the R1 and R5 relays in the top of the box... when that didn't fix my problem, I looked over the schematics a bunch more to try and figure out how this thing works.

Here's what it's doing. Every few selections, The second button latches in (the number button)... the motor scans, and then s1 locks in like it's supposed to. Then the rear wiper scans, and S2 locks in like it's supposed to... and then stays locked in. When S2 locks in, R1, the 'select pulse and latch relay', never disengages.

The manual says that there's a diode across R1, and that this diode makes a select pulse, a slight delay in R1 disengaging. So it's supposed to get it's power through S2, normally closed switch 3 and 4. When S2 engages, it transfers 3 and 4, and makes 4 and 5. That kills the power to R1, and the diode somehow (I don't quite understand that part) makes a slight pause until R1 disengages.

R1 is supposed to drop out, which turns off the latch coil, which unlocks the letter and number buttons, which kills the power to S2.

R1 isn't dropping out, so S2 never drops out, which leaves that selector coil locked on.

It's an intermittant problem... and I've noticed sometimes, R1 will drop out after a few seconds. Could this be a problem with that diode? How does the diode keep the coil energized? I don't understand the logic of that. It kind of sounds like it could be the issue since it comes and goes. I've looked at S2 switches 3/4/5 over and over, and it's definately working properly, making and breaking like it should. I've sat and stared at it though when the switch is open, and the R1 relay is still energized! It'll sit like that for a few minutes, but I don't like leaving it like that since it might burn up the selector coil that's locked on the whole time S2 is.

Any ideas? Thanks again for your help!
 
Last edited:
Hello Ron,

Is R1 a plug in relay or a soldered in type?
It doesn't matter whichbut if it is the plug in type replace it. If it is the soldered type unscrew the relay from the search unit (I think just one screw secures it), remove the plastic cover and check the four loop cables that are connected to the contacts.

I found an issue on one of these last month and it was the first time I had seen it even after working on the 1100 mech for over 30 years. two of these cables than have a thin coating of insulation on then had shorted together after the cables had become hot. I put some tape on them and away it went.

Please let me know how you get on.

Regards
Alan Hood
ami-man
UK
 
It's a plugged in one, it's one of the ones up in the top, with a blue plastic cover around it. I'll take it apart and see how the wiring looks inside it.

Thanks!

Ron
 
Alan, thank you for your help... I fixed it! The R1 relay under the plastic that you pointed me to originally, was magnetized. I disassembled it, beat the metal pieces with a hammer until they acted right, and then put it all back together and it works perfect now.
 
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