Hi all!
I just recently came into possession of one of these great machines although it is not completely functional (but close). There seems to be an issue with the tape transport (go figure), specifically an issue with the rewind and forward fast functions where those functions only appear to work under certain conditions. I know there are few threads on here and other sites that details issues related to my specific one but have not had much luck - I hope the pictures/video I provide in this thread can help others with similar issues and save time + money.
First a little background...When I received the 688 I immediately popped the hood open to inspect the capstan belt and lo and behold it had melted away. I am currently awaiting a replacement belt in the mail and temporarily placed a rubber band in its place which seems to work well enough. All the other functions of the machine (with the exception of recording, haven't tested that yet) appeared to be good until I placed a 72-minute, high-bias type II tape in the machine and tested the transport system. The 688 seems to play the tape just fine (without any distortion of sound, even) although has trouble with REW/FF where it either rewinds/forward fasts incredibly slowly, or attempts to but then seizes up and does not, as if there is no cassette in the deck.
At first I suspected a slipping idler tire or, worst-case scenario, a faulty reel motor so I focused in on that area. I applied some silicone lubricant to the gears and some synthetic [sewing machine] oil to the motor post in the hopes that this would resolve the issue but no dice. I kept playing around with the FF/REW functions and noticed something odd: when I unscrewed the tape deck assembly and stood it straight up, perpendicular to the machine, the functions worked almost flawlessly but when I set it back down in it's normal position, the same issues came up. I removed the reel motor to have a closer look and it seems to work as it should; I have no way of testing if it is providing the proper amount of torque but seeing as how it functioned as it should when the tape assembly was made to "stand up", I would think that it is. I checked the idler tire too and it looks like it may need replacing at some point down the road but it looks fairly good for the time being.
Here's a short video I made describing the issue right after I removed the reel motor:
https(colon)//photos.app.goo.gl/RRH5YiVjeJhDyMGG9
And here's another video showcasing the problem with the tape transport (where I "stand up" the tape assembly and show how the FF/REW functions work in this position)
https(colon)//photos.app.goo.gl/SbSp3XwojaLJWmzK7
please forgive my wordage as I am still very much an amateur at all this DIY stuff I called the tape assembly as "transport" so scratch that. Also just to clarify, when I note that "gravity" has something to do with the issue my train of thought was considering issues with the gyroscope (?) within the reel motor or the tape spools or something else due to the downward force of gravity in that resting position which is relieved when the tape assembly is placed in a "standing" position - hope that makes sense, haha.
Any help would be really really appreciated.
Thank you!
I just recently came into possession of one of these great machines although it is not completely functional (but close). There seems to be an issue with the tape transport (go figure), specifically an issue with the rewind and forward fast functions where those functions only appear to work under certain conditions. I know there are few threads on here and other sites that details issues related to my specific one but have not had much luck - I hope the pictures/video I provide in this thread can help others with similar issues and save time + money.
First a little background...When I received the 688 I immediately popped the hood open to inspect the capstan belt and lo and behold it had melted away. I am currently awaiting a replacement belt in the mail and temporarily placed a rubber band in its place which seems to work well enough. All the other functions of the machine (with the exception of recording, haven't tested that yet) appeared to be good until I placed a 72-minute, high-bias type II tape in the machine and tested the transport system. The 688 seems to play the tape just fine (without any distortion of sound, even) although has trouble with REW/FF where it either rewinds/forward fasts incredibly slowly, or attempts to but then seizes up and does not, as if there is no cassette in the deck.
At first I suspected a slipping idler tire or, worst-case scenario, a faulty reel motor so I focused in on that area. I applied some silicone lubricant to the gears and some synthetic [sewing machine] oil to the motor post in the hopes that this would resolve the issue but no dice. I kept playing around with the FF/REW functions and noticed something odd: when I unscrewed the tape deck assembly and stood it straight up, perpendicular to the machine, the functions worked almost flawlessly but when I set it back down in it's normal position, the same issues came up. I removed the reel motor to have a closer look and it seems to work as it should; I have no way of testing if it is providing the proper amount of torque but seeing as how it functioned as it should when the tape assembly was made to "stand up", I would think that it is. I checked the idler tire too and it looks like it may need replacing at some point down the road but it looks fairly good for the time being.
Here's a short video I made describing the issue right after I removed the reel motor:
https(colon)//photos.app.goo.gl/RRH5YiVjeJhDyMGG9
And here's another video showcasing the problem with the tape transport (where I "stand up" the tape assembly and show how the FF/REW functions work in this position)
https(colon)//photos.app.goo.gl/SbSp3XwojaLJWmzK7
please forgive my wordage as I am still very much an amateur at all this DIY stuff I called the tape assembly as "transport" so scratch that. Also just to clarify, when I note that "gravity" has something to do with the issue my train of thought was considering issues with the gyroscope (?) within the reel motor or the tape spools or something else due to the downward force of gravity in that resting position which is relieved when the tape assembly is placed in a "standing" position - hope that makes sense, haha.
Any help would be really really appreciated.
Thank you!