Changing the Head Block on my MX5050 B3

[astrotoy]

Hi folks, I would like some help. I have a 5050 B3 which came with a 2 track head block - no 4 track playback head.  Due to an alert from a list member (thanks, Joel) I was able to snag a 2/4 track head block - looks mint to me - on Ebay for about $130.  Now I am trying to switch head blocks. It looks like there are only two screws to remove to switch the head blocks. I took them out and the old head block doesn't want to move. I don't want to force things, just in case there is something else I need to remove.  Help!! Thanks, Larry

[ironbut]

From glancing at the exploded view of the headblock, it looks likes it's actually 4 screws (could be wrong). It may be hard to get at the other two with the hinged cover in place though.
Here's a link to Darkhorse's manual downloads and exploded view is located in the parts manual.

http://www.tapeproject.com/smf/index.php/topic,1545.0.html

[steveidosound]

From glancing at the exploded view of the headblock, it looks likes it's actually 4 screws (could be wrong). It may be hard to get at the other two with the hinged cover in place though.
Here's a link to Darkhorse's manual downloads and exploded view is located in the parts manual.

http://www.tapeproject.com/smf/index.php/topic,1545.0.html

I think that is correct from my old 4 channel 5050 (not B3).

Look at the replacement headblock for the 4(?) empty holes and match up with screws that need to be removed.
Just don't loosen anything that will change head alignment.

[DJ Darkhorse]

Hi folks, I would like some help. I have a 5050 B3 which came with a 2 track head block - no 4 track playback head.  Due to an alert from a list member (thanks, Joel) I was able to snag a 2/4 track head block - looks mint to me - on Ebay for about $130.  Now I am trying to switch head blocks. It looks like there are only two screws to remove to switch the head blocks. I took them out and the old head block doesn't want to move. I don't want to force things, just in case there is something else I need to remove.  Help!! Thanks, Larry

Hi,
Just looked, it's three screws, and they screw into the 3 tape guides, also you have to take off the head housing assembly as well. Section 3 of the Otari Parts list shows an exploded view.

Found this pictorial.

http://www.awardaudio.com/R2Rpictures/Otari-Headstack/index.htm
 

[ironbut]

I just thought I'd mention that there's nothing to say that the head block's been adjusted. Even if they are in fact optically aligned, it would still need some tweaking. And even if the heads are totally adjusted relative to each other and the guides within the headblock, it still doesn't mean that they'll line up correctly with the guides, tensioners and reel tables on the machine.
After installing a new/new to you headblock never play an important tape until you're certain that all the guides on and off the headblock are correctly aligned or you will damage the tape edges. Nothing will cause oxide shedding like poor alignment. A guide may be shoving the tape against the upper or lower guide edges around it (or even over in extreme cases).
The tape knows where it wants to go (most of the time) so guide alignment gets out of it's way and lets it do it's thing.

Head alignment is a whole different thing.

[astrotoy]

Thanks fellows, for some reason I didn't see that third screw - right in the middle!  I just changed out the heads. I played an old mono 15/2 tape and checked the tape path. Nothing was scraping - things look like they are going down the path with plenty of room on both sides. I turned it to play and the sound was nice and strong with the music centered in the sound stage. I then put on one of the old 4 track tapes and flipped the switch to 4 track and the sound was really fine. Looks like it lined up just about perfectly.  I'll have my scope program back in a couple of days so I can check the allignment with a couple of allignment tapes.  Thanks for all the help!! Larry