Fisher 8 track only playing 1 and 2

[Carbsandcaps]

I picked up a fisher cp-100 8 track player that won’t play programs 3 and 4. I’ve adjusted the head up and down with the set screw and can get program 1 to play when on program 4 but that’s with the screw all the way in. When it’s set just right for program 1 and 2 to sound perfect I get nothing from 3 and 4. The head only seems to be moving to 2 positions when the program button is pushed. I removed the solenoid and manually changed the program to watch the head. The plastic cam that’s moved to head seems to be ok.

This is a 2 and 4 channel player so I don’t know if that has anything to do with it. Anyone ever deal with one of these? I know 8 tracks have gone the way of the dinosaur but I’m working on my all fisher setup and this is one of the pieces.

 

[dhnash]

This unit is apparently operates in 2-channel or 4-channel mode. There are selector buttons on the left side of the front panel that are used to select either of these two modes. If 4-channel mode is selected, the unit will only switch the playback head between two positions corresponding to two 4-channel programs. The 2-channel mode must be selected to allow the head to be switched between four positions corresponding to four 2-channel programs.

 

[Carbsandcaps]

This unit is apparently operates in 2-channel or 4-channel mode. There are selector buttons on the left side of the front panel that are used to select either of these two modes. If 4-channel mode is selected, the unit will only switch the playback head between two positions corresponding to two 4-channel programs. The 2-channel mode must be selected to allow the head to be switched between four positions corresponding to four 2-channel programs.

The modes on the side are just lights. The big slider switch inside is what changes the lights. When I run it without a tape in it by pushing the power switch I can move that switch and it changes from 2 to 4 channel. I agree that it seems like something the 4 channel or 2 channel modes. The coils in the head all measure about 750ohms.

 

[dankik]

Since it is a 4-channel player with 4 head gaps, when in 2-channel stereo mode the physical head only has to move between two positions (as @dhnash says). The other set of two positions should be handled by electronic switching of the head signals (I would guess). Maybe the large slider switch has dirty contacts preventing audio in two positions. There should be a difference between cartridges that are 4-track and 2-track, another notch sensed by a switch or light beam. Maybe this switch is bad or misaligned? Have you tried cleaning it with Deoxit?

 

[Carbsandcaps]

Since it is a 4-channel player with 4 head gaps, when in 2-channel stereo mode the physical head only has to move between two positions (as @dhnash says). The other set of two positions should be handled by electronic switching of the head signals (I would guess). Maybe the large slider switch has dirty contacts preventing audio in two positions. There should be a difference between cartridges that are 4-track and 2-track, another notch sensed by a switch or light beam. Maybe this switch is bad or misaligned? Have you tried cleaning it with Deoxit?
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Ya I deoxit’d it a few times I’m assuming it’s in that circuit though. It looks like the 4/2 board is right under where the tap goes I think I’ll go there next