Yes. I used a regular pre recorded cassette tape just so I could more accurately test the speed. I had to have it set to low speed on the switch, and pitch control all the way down. And the reason I ask about the pinch roller is because when I push on the pinch roller to push it more into the tape, it slows it down because it puts more pressure on the tape and capstan. So the roller should be sitting where it normally does when it plays, but I was thinking the thinner space between the central bore and the outside of the roller would equate to less pressure on the tape and capstan, therefore allowing it to move faster. With no pinch roller pressure, the spindles move at near fast forward speed and so does the tape.
And yes I read his tutorial on rhe pinch roller and idler tire replacements, and I went to home depot to look for what he was talking about, but I thought it might be better and more economical to look at the packages of washers and o-rings that they had. I think the ones I put on are working decent but i guess I cat really tell until I fix this head block setting issue.
And oh okay I understand. I will just have to play around with the positioning of it then.
So just, which part has to come off to be re aligned? It looks like the belt would just pop off without taking off any of the wheels.
So how do you know the pre-recorded tape is playing too fast? Just by ear? I think in addition to the pitch knob there is a speed adjust trimmer on the pitch control PCB. You first adjust the pinch roller pressure, then use a test tape with a known frequency tone and reproduce the tone and adjust the trimmer until the frequency measured at the output jack of the 246 is equal to the known frequency on the test tape. Yes of the pinch roller pressure is too low, the takeup torque may overcome the capstan shaft and the tape may be slipping past the capstan shaft. First, you need to install the correct pinch roller, and secondly you need to adjust the pinch roller pressure using a spring guage in accordance with the instructions in the service manual. You really, really, really ought to have the service manual for that machine if you are doing this kind of open-heart surgery and wanting/needing to make these kinds of repairs/adjustments. Do you have the service manual?
Regarding the idler tires, no offense, but if you had the info for which parts to get, and you chose to do something different for whatever reason, don't expect it to work right, or that you will be able to get it to work right. If somebody told me what parts to get, I wouldn't consider something else at the risk of it not working right. There's a reason the particular washers were recommended by DrZee. Its up to you whether or not it is worth saving a few dollars to have the headache of trying to get it to work right.
I think your first objective IMO is get a service manual, and second get the correct parts.
Regarding the head base position, I'm attaching two pdf files to this post. One is the instructions from the 246 manual regarding the head base position adjustment. It was a little difficult to make sense of it, so I also grabbed the same instructions from the 234 manual which help to clarify. Refer to the 246 instructions as far as the adjustment trimmer identifier and location, but use the 234 instructions as a clarification on what you are supposed to do. You basically put the transport in PLAY and then STOP mode and power it off and then make a note of where the head base is sitting. You then turn the reduction pulley (the large white one with the 4 holes in it) by hand to see if you can get the head base to go lower. If you can, then on the 246 there is a trimmer R552 on the control PCB...you turn it on, put it in PLAY again and then STOP and tweak the trimmer to lower the head base position to the lowest position in STOP mode. You then repeat this a couple times to make sure its where it should be (i.e. PLAY, STOP, power off, note head base position, see if you can get it lower with the reduction pulley by hand and if you can, power up, press PLAY, then STOP, tweak trimmer, PLAY, STOP, shut it off and repeat the steps until the head base is in its lowest position when you hit STOP and power the machine off). If you can't ever get the head base to its lowest position in STOP within the sweep range of the trimmer then you will need to figure out what needs to be disassembled and what gear teeth need to be adjusted so the adjustment can be accomplished within the trim range of R552.