Rebuilding a Pioneer CT-F900 Transport

Timely thread.

I purchased a belt kit for my CT-F900 a year ago and it looks like I am about to find some time for this project. I hope it goes well, but it is nice to know there are people that have already gone through the process. I might have a question or two for you...but I hope not. :D

Thank you for the progress report.
 
ct f900 repair ... trouble with "play"

Long story short, I've changed the belts and idler wheel. With transport unit out, everything functions as it should. It's all cleaned, lubed etc. When reassembled, it will not play. The FF / REW work fine and are strong ... even holding the spindle with a little tension. So I think the reel motor is ok ... would you agree?

Two things that I do not happen when I press play are the brake solenoid and the reel motor do not activate. The motor does not even try to spin. If I move the belt it spins freely. The brake solenoid works fine with FF /REW not at all in play. The play actuator seems to try to activate but without the brake plate lifting it is unable to function properly.
I'm stumped at this point.

I did not clean the reel motor because, as I said above, it seems very strong when running FF/ REW and I would think that would require more torque then when it is driving the reel spindle in play.

Any ideas you could offer me would be greatly appreciated. VZzappa
 
Sounds ike it is stuck in pause mode...broken or pinched wire? head plate jammed, so it cannot go up and down?

Good luck,
Rich P
 
I just spent 6 hours replacing my belts. Got it aback together. FF and RR work much better than they did but now the take up reel only works sporadically. It will play fine for a few minutes, and then the take up reel stops spinning. A little tape starts to accumulate near the right pinch roller and the transport stops shuts off. There is a little "hitch" on the right take up reel when it does play... a mild off center spin is the best way I can describe it. It take several tries pushing the play button to get it to even play for those few minutes. It seems to be playing at the correct speed, but something just isn't right.

Any ideas would be greatly appreciated. BTW ...the instructions that came with the belt kit were very inadequate...this thread saved me, and got me to where I am. For that I am very grateful, but obviously still not quite there.
 
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I decided to take a swab of alcohol to all parts while moving that were accessible. I did this without a cassette installed. It seems to be playing very well now. There might have been just enough slipping going on somewhere that the alcohol corrected something. I played an entire tape and so far no problems. I didn't rebuild the motors, but I am not even sure that was the issue. I didn't replace the pinch rollers either.

I got this deck second hand, and am not sure of its history, but someone had been into this unit before because there are TWO wires spliced onto one of the pigtails and threaded through two holes in the back. I included a few pictures of these wires and am just a little currious why that was done or what the two wires do that they were spliced to???? Pics below.

When I got this deck 5 years ago I was told it hadn't been used for some time, and the first thing I noticed was that the blue VU meters and tape counter were hardly lit up. The longer the unit played, the brighter these areas got. They are fairly visible at this point, but they were nearly totally faded again yesterday when I turned this unit on for the first time in over a year.

In the first picture in post #5 there seems to be a wire clip just to the left of the RED A. I don't seem to have this clip and was wondering about that as well.

pustelniakr...Once again THANK YOU so much for your detailed thread. I hope that my deck continues to perform correctly, but I have to wonder how the little bit of alcohol cleaning fixed the play issue. My transport is nearly dead silent as well.
 

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at last success .....

I got my deck working tonight and thought I would pass along what finally did the trick.
Today I tore the transport apart (again!) and this time, cleaned and lubed the reel motor. Like I said above, it seemed strong but I was running out of ideas. I reassembled everything and still no play. I was starting to think I would have to start parting this deck out.

Just on a whim, I re-soldered the connections on the reel motor even though they were still intact and working the motor. I hit play and it started working. One of them must have been marginal but I’m amazed the FF/REW worked fine. After 3 weeks, on and off, of working on it I can now get everything back together.

The main thing I have learned from this rebuild is ... reel to reels are a lot easier to work on! :D VZzappa
 
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I was excited that mine got through an entire tape after the new belts, but it was short lived. My deck is now shutting off after a few minutes. Those reel motors are impossible to find, so I guess I am going to have to risk trying to rebuild mine. It sucks that everything has to be take back apart to get to it. At least I have the experience of taking it apart under my belt.
 
pustelniakr: Thank you for this excellent thread. Also with this help I rebuild this nice deck.
Cleaned everything in ultrasound cleaner, lubed, belts+idler changed, adjusted and calibrated. It records and play perfectly.
Thank you!
Roman, Prague, Czech Republic
 

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pustelniakr: Thank you for this excellent thread. Also with this help I rebuild this nice deck.
Cleaned everything in ultrasound cleaner, lubed, belts+idler changed, adjusted and calibrated. It records and play perfectly.
Thank you!
Roman, Prague, Czech Republic
Nice, and nicely done. Congratulations. They are nice decks, and yours turned out quite pretty.

I actually prefer the CT-F900 to the CT-F950. The only thing missing is metal tape capability. Metal tape is pretty rare, and too expensive when it can be found. The CT-F950 is a compromise toward metal tape, and requires a balancing act to get all of the tape types recording in spec. It is almost as if metal tape was an afterthought. The CT-F900 dials right in for all suitable tape types. For metal, I would go for the CT-F1250, which also dials right in for all of its tape types, which include metal.

Where did you get your calibration tapes? Which ones did you use?

Enjoy,
Rich P
 
Hi Rich,
I used my own made mirror cassette to set tape path, then I demagnetize head and path, then azimuth with tape 6.3kHz. PB level with P-4-L300 for 0dB at 160nWb/m which is 450mV on output, 0dB on meters (output potentiometer in middle) After that I am checking PB equalization with another tape which I have.
Then record mode and again going through all steps to check if everything OK.

In short, I am trying to follow manufacturer recommendations, but sometimes it's difficult due to worn heads for example. My rule: what is loaded to the deck, must be played back 1:1 :)
And always is good to use own ears to verify settings, correct? :)
 
Uh,
I switch on deck after a week and found strange thing, R channel indicator is flickering, flashing, blinking or how to say, L channel is stable=show perfectly 0dB...
Anyone seen this kind of behaving?

PB and REC is OK on both channels, sound is perfect.

It looks that something on indicator amp or indicator assy... I hope that vacuum tube display did not give up:(
 
Good afternoon, very grateful for the post, it can not be better. Thanks to you I have changed my belts CTF 900. Now I will fully enjoy it. One last question, the cassette compartment light does not work, I decided to change it but not its voltage and power, if someone would kindly give me some information would be very grateful.
 
Good afternoon, very grateful for the post, it can not be better. Thanks to you I have changed my belts CTF 900. Now I will fully enjoy it. One last question, the cassette compartment light does not work, I decided to change it but not its voltage and power, if someone would kindly give me some information would be very grateful.
Service manual says 8v, 120mA.

Enjoy,
Rich P
 
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Thank you for the information. Greetings from Sevilla (Spain).
 
I was asking you if you'd start a thread about that, since you know these decks forwards and backwards.

Charles.

I have no current plans to generate cassette deck calibration thread, because each deck, not each model, each deck, presents individual challenges to the calibrator. Tape deck calibration, for cassette decks in particular, is not a DIY operation.

Detailed technical knowledge of magnetic recording principles is required.

A good tome containing the basics is "Techniques of Magnetic Recording," by Joel Tall (1958). It is an old book, but the principles are still sound.​

Understanding bias is critical, as proper equalization is impossible without it. Refer to "Biasing in Magnetic Tape Recording," by John McKnight of Ampex Corp. (1967), and "Bias," by Terence O'Kelly (date unknown, from the BASF "The Inventor's Notebook, Technical Bulletin #3."

All of this knowledge is in addition to the technician's knowledge of general electronics, which is covered fairly well in "The Art of Electronics," by Paul Horowitz And Winfield Hill (2001).​

"Calibration" means to adjust deck performance (play, record, Dolby) to specified requirements, while maintaining traceability to fixed industry standards.

If the traceabilty is not involved, a deck can be calibrated to perform somewhat well in isolation, but tapes made on other machines will sound bad, or tapes made on the single machine will sound bad on other machines.​

Proper calibration begins with playback calibration steps requiring special test tapes that are calibrated to industry standards. Record calibration then works with specified input levels from signal generators, built upon adjustments made during playback calibration. If you do not have those calibration tapes, you should not attempt a DIY calibration.

You cannot make your own test tapes, without access to linkage to verification to the standards (tape speed, flux density, frequency response, azimuth alignment, etc.), and without access to special recording equipment.

There are test tapes flowing into the country from China, via Ebay. I am very dubious as to quality and traceability, since China is into so much counterfeit production. One day I will pick up a tape or two and see how they compare to verified tapes. Until then, I do not recommend using such Chinese tapes for calibration. There is a member of tapeheads.com that also represents himself as a source for calibration tapes, but I have not tried any of his either.​

Here is a list of calibration tapes that I have, and require, to perform cassette deck calibration:
  • Mirror Cassette (Sony MC-109C) - Used to visualize passage of tape through the transport, and across the various rollers, guides, and heads.
  • Torque Meter Cassette (Teac (MTT-8111 and Sony TW-2422) - For measuring reel torques.
  • Wow & Flutter / Speed Cassette (Teac MTT-111N) - To set tape speed and to measure transport performance.
  • Azimuth Level Cassette (Teac MTT-255 and/or MTT255C or MTT-114N) - To provide for the adjustment of fine azimuth relationship between tape and playback heads.
  • Dolby Level Calibration Tone Cassette (Teac MTT-150) - To set playback levels required for proper interaction with Dolby circuitry, as well as playback level and meter representation.
  • 315Hz Level Cassette (Teac MTT-212N) - For proper base line playback levels, and foundation for equalization adjustments.
  • Calibration / Frequency Response Cassette (ABEX TCC-162) - For overall performance verification, Dolby playback and frequency response adjustment, at levels appropriate to vintage Pioneer cassette decks (freq. response is at -20db).
You will also need quality, lightly used or fresh blank cassettes of all four tape types addressed by vintage Pioneer cassette decks. This is what your decks will be calibrated to. There was light enough variability between tapes of specified types, by various manufacturers that a deck calibrated to one manufacturer's tapes will perform well with others. The exception is metal tape, where there was a pretty wide performance spectrum. There you will have to choose one and run with it. Here is what I calibrate to:
  • Standard Bias: TDK D90
  • High Bias: Maxell XLII
  • FeCr: Sony Duad
  • Metal: Teac MDX (Maxell MX-S tends to be a bit too hot (coercivity too high) for vintage Pioneer decks)
Like AM/FM/Stereo tuner calibration, tape deck calibration is some of the most complicated and requires specialized equipment to perform.

Such equipment must be, itself, properly calibrated to industry standards. Also, such equipment is generally no longer manufactured (to my knowledge). Attempting to perform tape calibration without the special test equipment is very cumbersome, if not impossible, in some stages.

You need signal generators and milli-voltmeters, calibrated to dbV, with proper loading, to properly set levels and frequency response, unless you know how to create proper loads and do the proper math conversions.​

Here is a list of test equipment that I have, and require, to perform tape deck calibration:
  • Leader LMV-185A 2-Channel AC Millivoltmeter - I use two of these, one to measure stimuli and one to measure response (input vs. output). This means that frequently, I am measuring 4 test points simultaneously. This meter is calibrated in the required units, dbV.
  • Leader LFM-39A Wow & Flutter Meter - To measure transport stability and speed.
  • HP 8903A Audio Analyzer - To provide for proper adjustments referencing distortion.
  • Sound Technology 1700B Distortion Measurement System - To provide for proper adjustments referencing distortion.
  • Leader LAG-126S Audio Signal Generator - To provide proper stimulus tones at required levels and loading. This generator is calibrated in the required units, dbV.
  • Fluke 8060A True RMS Multi-meter - I use two of these at a time, in places, to provide various internal measurements and comparisons (voltage, frequency, relative voltage, etc.)
Calibration to the varying tape types presents many difficulties, since the various adjustments are interactive between tape types, and with other calibration adjustments.

Here is where the experience, skill, and art come into play.

Knowledge of how the mechanical elements of the transport affect calibration and performance is also, generally, gained by significant experience.

Disregard this statement to the peril of your gear. You could easily wind up with pretty vintage paperweights.​

Bottom Line:

Remember that you have been warned. Cassette decks with botched calibrations are especially unpleasing. The compact cassette was not originally designed for HiFi reproduction. Rather, it was designed for dictation machines. HiFi designers successfully pushed the envelope, and were able to squeeze serious performance from this medium. However, since most performance characteristics are pushed to the boundary for the medium, any divergence from correct is readily apparent (wow and flutter, tape path stability, head azimuth, bias settings, equalization curves, Dolby curves and levels, etc.).​

Enjoy,
Rich P
 
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I would just like to say thank you and let you know I appreciate very much what you have done here and elsewhere on this site. Taking the time you have to help others diy is becoming a thing of the past, please keep up the excellent work.
Bob.
 
006.JPG009.JPG When I was changing the belts on my Pioneer CT-F900 I apparently unplugged the yellow wire from the Standard/CR03 microswitch. Can anybody tell me where this plugs in.
 
View attachment 971504View attachment 971505 When I was changing the belts on my Pioneer CT-F900 I apparently unplugged the yellow wire from the Standard/CR03 microswitch. Can anybody tell me where this plugs in.
I don't have access to an open unit at this time. The interconnect diagram, and the motherboard foil pattern drawing are in conflict. In the front, left corner of the motherboard is a pin, labelled 2A. Look straight back from there to the center of that side of the motherboard, and you will see a pin labelled 1A. Whichever of those that does not have a wire connector on it is likely where your wire goes. The other pin will connect to to another tab on the same micro-switch.

Report back, so I can correct my service manual.

Enjoy,
Rich P
 
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