Continuing Saga: Errant Pioneer

cason

cason

AK Subscriber
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Hey guys,
As some of you may remember, I’ve been struggling to solve several issues with my CT-F9191 (ser.# XI 1317228) for a while now. After replacing belts (some of them more than once) and the tape movement sensing switch, all functions are now operating as they should – except it’s playing at warp speed. The capstan motor speed control variable resistor, which is mounted on a small IC board inside the rear of the motor case, not on a separate outside board as indicated in the service manual, will only adjust the speed from very fast to very, very fast. The motor is labeled RXM-018b. I’ve taken voltage readings at the motor leads: power on, tape in place, STOP mode = 12.66v; PLAY mode = 12.55v; REWIND mode = 12.42v; FF mode = 12.43v. I believe I’m in over my head. Anyone have suggestions on what I should be looking at, or is it time to get in line for some “bench time with the rabbi?
Thanks,
Bob
 

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RXM-018b sounds to be a replacement motor for your deck - if if runs way to fast, it has a defect, or the belt could run at the wrong place of the pulley.

can't remember if it's a standard 2400 rpm motor ..
 
cason said:
Hey guys,
As some of you may remember, I’ve been struggling to solve several issues with my CT-F9191 (ser.# XI 1317228) for a while now. After replacing belts (some of them more than once) and the tape movement sensing switch, all functions are now operating as they should – except it’s playing at warp speed. The capstan motor speed control variable resistor, which is mounted on a small IC board inside the rear of the motor case, not on a separate outside board as indicated in the service manual, will only adjust the speed from very fast to very, very fast. The motor is labeled RXM-018b. I’ve taken voltage readings at the motor leads: power on, tape in place, STOP mode = 12.66v; PLAY mode = 12.55v; REWIND mode = 12.42v; FF mode = 12.43v. I believe I’m in over my head. Anyone have suggestions on what I should be looking at, or is it time to get in line for some “bench time with the rabbi?
Thanks,
Bob
Click to expand...
I agree with jan_stevns, check to make sure the belt is in the pulley groove. Also according to the SM pinch roller tension can affect playback speed. I haven't dug deep enough to tell if your main motor's input voltage is in spec. Your FF/RW functions are driven by the FF motor RXM-019, Playback by RXM-018. It's possible that the internal pot on RX-018 has gone bad, but since it now sounds like Alvin & the chipmunks since the belt change I'd look at the belt position on that motor pulley. Keep it simple and get it in the groove! Hope this helps. I also have a 9191 and 8282 that I started working on but due to the job market I have to wait before putting money into them. Both are very clean with nice wood and need a complete belt/drive pulley replacement along with some audio hum and balance issues. The CT-F 9191 is a keeper.
 
Jan and Eagle,
Thanks for the replies. I have the belt in the groove now. After first changing it, it did ride up on the rim and cause increased speed because of the larger diameter of the rim (as compared to the central portion of the pulley). This is one of the belts I changed twice.
As far as being a replacement motor, it may be. But when I first got this deck and put a new capstan belt on it, it ran at proper speed. I used it a while, but then started having issues that I ultimately determined were caused by the tape movement sensing switch. And now this speed issue. Seems I get one issue resolved and two more rear their ugly heads.
 
cason said:
Jan and Eagle,
Thanks for the replies. I have the belt in the groove now. After first changing it, it did ride up on the rim and cause increased speed because of the larger diameter of the rim (as compared to the central portion of the pulley). This is one of the belts I changed twice.
As far as being a replacement motor, it may be. But when I first got this deck and put a new capstan belt on it, it ran at proper speed. I used it a while, but then started having issues that I ultimately determined were caused by the tape movement sensing switch. And now this speed issue. Seems I get one issue resolved and two more rear their ugly heads.
Click to expand...
Has the playback speed calmed down now that you have the belt in the pulley groove and does it stay there? If the belt keeps to want to ride on the high side make sure it's not twisted. Another option would be to realign the pulley on the PB motor, someone may have moved it or the locking screw may have come loose just enough. Hopefully you have remembered or marked the exact position of the motor speed pot before adjusting it. From your new post it doesn't sound like a motor or pot problem, but improper installation or where the belt wants to track on the pulley. Glad to be of help. Working on a CT-F1250 can really try your patience!
 
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I may have the motor for your deck. I'll check if it has adjustment screw(s) for the speed.
 
Sounds like he has a 15 ips motor in a 7 1/2 ips deck. Did you replace the capstan motor recently? Maybe the pot on the speed control board has gone south. Does the machine have a variable/fixed pitch control button on the front panel like some Teacs? If so It may be acting up.

Phil
 
Eagle1,
The belt is now riding in the proper position on the pulley. I've been keeping an eye on it and there is now no tendency to ride up on the rim. I don't believe that is any longer an issue.

The variable resistor for motor speed control seems to be working, as well. Adjusting it just varies motor speed (or play speed) from very fast to very, very fast. I'm wonering if there is a resistor or transistor in the circuit that supplies power to the capstan motor that has failed, and is providing too much voltage to the motor.
Any thoughts?
 
cason said:
Eagle1,
The belt is now riding in the proper position on the pulley. I've been keeping an eye on it and there is now no tendency to ride up on the rim. I don't believe that is any longer an issue.

The variable resistor for motor speed control seems to be working, as well. Adjusting it just varies motor speed (or play speed) from very fast to very, very fast. I'm wonering if there is a resistor or transistor in the circuit that supplies power to the capstan motor that has failed, and is providing too much voltage to the motor.
Any thoughts?
Click to expand...

none - besides replacing the motor.
 
cason said:
Eagle1,
The belt is now riding in the proper position on the pulley. I've been keeping an eye on it and there is now no tendency to ride up on the rim. I don't believe that is any longer an issue.

The variable resistor for motor speed control seems to be working, as well. Adjusting it just varies motor speed (or play speed) from very fast to very, very fast. I'm wonering if there is a resistor or transistor in the circuit that supplies power to the capstan motor that has failed, and is providing too much voltage to the motor.
Any thoughts?
Click to expand...
Do you have the service manual? If not I can direct you to where you can get it for free.
 
Eagle1 said:
The motor can be rebuilt but usually for the opposite reason, too slow or not working. It's very possible that the internal pot is not doing it's job. I've never had to adjust them on any of my cassette decks. I see that Oaktree has the 018 motor at $55, ouch. http://www.oaktreevintage.com/Pioneer_Stereo_Parts_Salvage_Units.htm
Click to expand...

the pot seems to be working since speed can be adjusted from very fast to veryvery fast - gives me reason to replace that motor.

Would think any suitable motor can be used in the deck - if one can figure out if it's a CW or CCW motor, and it's nominial speed (rpm)

$55 - yickssss!!!
 
Eagle1,
Yes, I have the service manual. Problem is, it shows a small rectangular PC board with speed adjustment variable resistor on it, OUTBOARD of the capstan motor. My deck does NOT have that PC board, just the board inside the motor housing. I'm wondering if this was a production change somewhere along the way, or if someone before me has done a major alteration to this deck. I'm beginning to think it may be looking more and more like a "parts deck."
Bob
 
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