auto stop randomly engages on Pioneer HR 100

[jdwk]

I was attempting to use the pioneer HR 100 to locate the splice on a recently repaired tape. I usually use the "one" setting on the auto stop knob because it doesn't require the head to move from 4 to 1 like the "end stop" does, it just "stops" when it hits the splice without the click of the channel change. Now, If the knob is in the "one" position, the deck stops within two minutes and the auto stop light comes on, but of course, no splice, it just randomly stops. Putting the stop control on "all" and letting it stop after the channel switch from 4 to 1 it works as it should. anyone have any idea what could be causing the problem? Cleaned heads, foil detector. and the capstan, and it had no effect. any ideas would be appreciated.

 

[Stereo2]

I would say that the 8-track function switch control ( one /endless/ all) has dirty contacts.

 

[jdwk]

I have D5 fader lube, that I have used on volume controls. Can you use that on a switch like that or should you use one of the other Deoxit formulas?

 

[Stereo2]

Deoxit formulas for switch contacts.

 

[dankik]

Here is the schematic for the Program and Function switches and head solenoid. The function switch is shown in the "One" position (blue). When the foil tape runs past the Contact Piece it applies power to the Program Switch (S7) which applies power to the solenoid. When in the "All" position the Contact Piece drives the solenoid directly. When in the "One" position the sensor goes through S8-2. Clean and check continuity through Function Switch S8-2.

 

[jdwk]

thanks so much for the effort!

 

[jdwk]

here is where it gets interesting, I tried 2 other tapes, put the switch in the same position, no problem, as soon as I put the tape in that had the problem, it returns and automatically stops. I going to try other tapes, and see if others do it, or don't. But now it seems ONE tape makes this happen.

The tape in question, is a maxell from the quad era, the ones with the plastic piece in the upper left corner that you remove if you are trying to record a quad tape, and I noticed something.....maxell used a different tape formulation in the covert a quad blanks, that changes as soon as they arent the ones you convert to quads, if you happen to have noth kinds of maxell tapes, have a look at them side by side.....wonder if it's some difference in the oxide. the tape sounds good and doesn't have dropouts. who ever recorded it, had a deck with the mechanical pause usually found on the better units, sounds pretty close to a normal oxide cassette.