Restoring a Pioneer RT-909 Reel-to-Reel

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The 24 volt power supply and the H-Bridge are related. The H-Bridge circuit is the 'last step' on the Control B board before voltage is supplied to the capstan motor control board. If you are not having capstan motor problems, don't look to the H-Bridge or 24 volt power supply circuits. The tape motor tension controls are difficult on some Control B boards. Sometimes the adjustment sequence in the manual need to be made multiple times. Adjusting one of them may require readjusting others. I have tried to make sense of the tension adjustment circuits several times and come away without understanding what I am looking at! The circuit is primarily transistors, capacitors, and the trim pots that are used for the adjustments. Each time I have difficulty with the tensions I presume faulty components, but have found none. So as far as this goes I am sometimes as in need of help as you. On other decks, once the adjustment sequence is followed and then repeated several times everything is Good! If Rich, Matrix, Mark The Fixer, Numistrek, or one ot the Pros is listening any response would be super.

Thanks,
Walter
 
The issue you are addressing has aged and is no longer current.

The adjustment pots are standard pots which will become iffy with the time that has passed. DeOxit is not a good fix here. Instead pot replacement is better. Take up torques should be adjusted to the higher end of the acceptability range, while the back torques should be adjusted to the lower end of the acceptability range. Several passes should be taken, until a pass can be made without making any change.

In an attempt to keep the original pots, note their positions (mark the pots), then, with power off, rotate each pot back and forth many times, and return it to its marked original position. Then go through the adjustment procedure, several passes until the unchanged pass can be made. These decks are not hyper-sensitive to the torques, but they can get out of adjustment and cause problems. A slight amount of teflon-bearing Tri-Flow on the motor bushings (a drop or two only) will improve performance and torque adjustability, and will make it easier on the drive circuitry.

Note that capstan torque is not adjustable.

You need to ensure that the brakes are completely lifting, also.

Enjoy,
Rich P
 
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Ok my 909 restore is moving along . All the mechanical and recapping is done. The heads assy is back from JRF and needs to installed. I went over budget, but I had to make some decisions. 1. the upper ball joints were missing ,replaced .2. My playback heads were shot ,replaced with good used (relapped, edged slots , polished and aligned). JRF is a good company they did a nice job and explained everything to me.They also give you all the test reports of your heads. The screws are very soft some heads were already stripped out (capstan motor mount) some were just so tight they stripped. Ace hardware had all but one size (2.6x5mm)which a found at a RC cars hobby shop. I did re flow some solider joints(pre amp) but not all, there were to many IC's and really close joints. I thought I might do more harm then good. Well I will know soon if I have a very expensive paper weight .
Hi Every one talks about recapping but no one tells where you can get the capacitors , resistors and diodes. I have only been able to find one capacitor from radio shack. It is the big blue on for the control b board. can't even find the motor run capacitors. Any help would be appreciated. Thank you, Kim J
 
Hi Every one talks about recapping but no one tells where you can get the capacitors , resistors and diodes. I have only been able to find one capacitor from radio shack. It is the big blue on for the control b board. can't even find the motor run capacitors. Any help would be appreciated. Thank you, Kim J
Read this post and the ones above and below it: http://audiokarma.org/forums/index....ioneer-rt-909-reel-to-reel.93227/#post-940167

Look here for components: http://www.digikey.com/ or http://www.mouser.com/

Be careful. Methinks thou mightest be biting off a bit more than thou canst chew. Not mocking. Just a word of caution.

Good luck,
Rich P
 
I'm a newbie into the Reel to Reel world and extremely excited to learn everything about this beauty.

I'm doing some basic restoration (if apply) and at the moment I'm deling with some extra parts after removing and replacing the pinch rollers.

I'm following the service manual but the two guys on the right are not shown there.

Are these part of the pinch rollers?

Thanks so much guys.

 
Those look like 2 out of 3 screw assemblies that hold the flanges to the hub of a metal 10" reel. They are not part of the pinch rollers.

Enjoy,
Rich P
 
Those look like 2 out of 3 screw assemblies that hold the flanges to the hub of a metal 10" reel. They are not part of the pinch rollers.

Enjoy,
Rich P

Thank you so much Rich for the prompt reply!

You're right and I remember now. I took those screws from a broken reel as spare part.

I need to exercise my memory for sure.
 
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Hello Rich,
Any chance you could advise me on finding some specific transistors for my RT909? I have (paid others to) restore this deck, and it's working really nicely except for recording. The bias circuit transistors (Q922 and Q923) on the RWX340 (motherboard) circuit board are failing intermittently, causing the recording capability to just go away. I have had the transistors troubleshot (?) and they come back to life when cold-sprayed, but they die again after minutes to hours of really spectacular recording. If these transistors are basic off-the-shelf bipolars or fets (I think they are based on the schematic from the Service Manual addendum I downloaded from HiFi Engine), I would think Mouser or DigiKey would have them. Problem is, I can't figure out what kind or how to search because the only additional info from the schematic says "2SCI382-Y" or "2SC1382-Y", depending on whether it's an "I" or a "1" (can't tell from the font used on the diagram). So, long question even longer, do you know how I might be able to track down some replacement transistors to swap into the bias circuit? Any insight would be most appreciated. Thanks so much!
Incidentally, do you still do work on these machines? I would consider paying you to get it recording reliably as I really have invested a lot so far getting this deck to the state it's in now.
Best,
Keith J
 
Thanks for the info Rich, I'll look into this substitution. Oh, and apologies for my breach of etiquette. I'll keep in mind for future interactions.
Keith J
 
Need some help over here!

I was lucky enough to remove three out of the four screws but the last one (thanks, Good it is located on the upper right side) is giving me some stress.

The screw got stripped and now I'm dealing with the options to remove it correctly. Bought the screw extractor set but is not working as expected.

Any advice would be really appreciated!

UPDATE (2/2/17)
Finally I was able to remove the stripped screw with the Vampliers screw pliers (Vampire tools International) This little tool really did the trick.
 
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The capstan on my reel tape is not working. Pinch rollers engage when playing both directions but no movement.

What is the right way to check if the problem is on the capstan or motor control assembly?

Capstan belt is brand new as well as the pinch rollers.

 
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Hi There.
I am new member. I had a RT-909. It plays, FF, RV ok. The only issue is when I record, it's not fully erase the tape. It erased but still have sound from previous record. I clean the erase head many times but it did not help. Is there anyway someone can point me to the right direction what to look for? Thank you
 
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