Restoring a Pioneer RT-909 Reel-to-Reel

[pustelniakr]

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

I would be better if you start your own thread , so this one can remain on topic. That way the proper attention can be given to your problem.

A short answer would be that your tape may not be making intimate contact with the erase head, or not passing across it properly. Otherwise, the erase head may be defective, or the deck may require a correct alignment/calibration, which for most folks is not a "fix it yourself" task. Specifically, you may not be supplying enough erase current to the head. Generally, if erase current is changed, recording bias will need to re-adjusted , and that leads to other adjustment requirements, etc., etc. etc.

Good luck,
Rich P

 

[RanDibble]

Above is good advice.

I recommend as a stop gap effort is to use a Bulk Eraser and use it properly.

I always bulk erase prior to recording !

 

[LinhTrade]

Thank you Rich and RanDibble. I will leave it as is and buying a Bulk Eraser. I thought if there is some board that I could check for voltage that supply to the erase head.

 

[ProUser]

Hello everyone,

I'm new to the board and thanks to @pustelniakr I am well on my way to restoring my new RT-909

I've done everything Rich careful wrote out except recapping the circuits and re-lapping the heads, turned it on and everything seems to be working except I am only getting L channel output, no right channel (moving left to right knob seems to be working because moving to the right there is no sound and left makes it louder). As I test I also tested the input signal and both channels work, so I am little stumped. Any suggestions in the right direction would be much appreciated.

Also can anyone chime on on how I can clean the heads and this green stuff which seems to be in various places all over the unit.

Thanks

 

[pustelniakr]

If it worked before, maybe you broke a wire.

Enjoy,
Rich P

 

[ProUser]

If it worked before, maybe you broke a wire.

Enjoy,
Rich P

Hey Rich,

Thanks for your reply, when I got the unit the power cable was severed, belt and rollers melted and so much old lube nothing moved. I have no idea how well it worked before, I guess my questions is how would I go about troubleshooting my issue. Where should I start?

Also what product can you recommend to remove the green stuff on the heads, and how I should go about cleaning the heads.

Thanks

 

[pustelniakr]

The green stuff is likely yellow metal corrosion. A metal polish may help, but alot of disassembly will be required. As is, it is likely only cosmetic.

Unless you are a technician, troubleshooting will be difficult, and possibly, not a DIY operation. I suggest that you start your own thread, so you can get the appropriate focus, and see if a remote tech can guide you. One help will be if only one channel plays in reverse as well.

Enjoy,
Rich P

 

[ProUser]

The green stuff is likely yellow metal corrosion. A metal polish may help, but alot of disassembly will be required. As is, it is likely only cosmetic.

Unless you are a technician, troubleshooting will be difficult, and possibly, not a DIY operation. I suggest that you start your own thread, so you can get the appropriate focus, and see if a remote tech can guide you. One help will be if only one channel plays in reverse as well.

Enjoy,
Rich P

Thanks Rich

 

[torivman]

Rich:

Great guide, I am just starting a restoration and took the tension rollers apart, only to find that the ball holder and 3 nylon balls are missing! Is this normal? The lower ball tray and 3 balls was there...

Was this possibly a later model? was this part eliminated?

thanks!
AO

 

[pustelniakr]

There are two versions. Just make sure that you put it back together the way it was when you are done.

Enjoy,
Rich P

 

[DeAl66]

Interesting... I didn't know there were 2 versions.
Up to now I restored 2 RT-909's and both had the (upper) ball tray with 3 nylon balls. A third RT-909 is waiting...

@ torivman, can you please share the S/N of your unit, just to understand when this tension roller version was implemented?

Thanks,
Alain

 

[torivman]

I completed the rebuild on the tension arms and they seem to work fine without the upper ball holders (may need to add a little damping fluid to one to slow down the damping). So either this was a different version or the tension arms just don't need that part! I guess it is possible that a previous repair tech lost the nylon balls and then just decided to remove the part all together because they otherwise seem exactly the same?

I will send the serial number tonight when I'm back at the repair!

One other question, as you can see in the pic I posted, yesterday, there is also a missing black plastic washer, any idea where I can get another?

Thanks
AO

 

[torivman]

see pic for s/n

 

[DeAl66]

Your RT-909 was produced in 1982 (C) - November (K) so that's one of the later units as they were built from 1978 and sold till 1984.
I'm still in doubt if the upper ball tray was left out on purpose during production, or gone missing due to a repair afterwards on your unit.
I think the latter may be the case as you found a black plastic washer and AFAIK the RT-909 always and only had clear nylon washers.

I live in Europe and so far I did not find a supplier of these thin nylon washers (thickness 0.3 mm and 0.5 mm)...

Alain

 

[pustelniakr]

I will say this again, the RT-909s of later years in the production run had tension roller assemblies with fewer parts. The newer ones worked as well as the older ones, and in a similar manner. Most units have the older construction. As for whether your unit has the newer version, I don't know from here. I have restored countless numbers of these units and know what I am talking about.

As for missing parts, that is certainly possible, since there are quite a few ham-handed techs out there that lose parts during a repair and don't make it right, or inform their customers. I have had excellent support in the past, from Oak Tree Vintage, when it comes to small, missing parts. They have even sent me the occasional Teflon washer or such by putting such in a shipping envelope for me at no charge, for shipping or the parts. Don't expect that yourself, but I have had such good support from them.

Good luck,
Rich P

 

[torivman]

Rich, I actually found another post on this thread regarding the same missing ball tray, so I think it is normal,

Thanks

 

[pustelniakr]

I seem to recall so. Post me a link here, and I will update my post up front, to avoid future confusion.

Enjoy,
Rich P

 

[Tricake]

I made a PDF with much of the work of Rich and some small updates that resulted from the discussion.
Feel free to have a look and if you want to contribute I can share the source as weel (LyX).

http://blog.affossati.net/2018/03/pioneer-rt-909-restoration/

Thanks to Rich and all the contributors!

 

[torivman]

The previous post noting the same missing ball tray can be found here, I believe it was also a later model as mine is (1982):

http://audiokarma.org/forums/index.php?threads/restoring-a-pioneer-rt-909-reel-to-reel.93227/page-11

I'm moving along nicely on my restoration, two things I noticed:

When I re-assembled the capstans, I noticed the back of the capstan where the nylon ball sits does not actually make contact with the wall of the motor assembly, is that normal? Seems to function fine.

Also, my newly tired pinch rollers, are in, but one seems to be slightly wavy , will that effect wow and flutter? Will try to even it out.

Next steps will be to send out for relapping and then calibration, when I have the $$, but all seems to be working fine mechanically!

thanks

thanks

 

[pustelniakr]

A very light lack of contact with the capstan balls is normal. The capstans do float just a tiny bit.

Contact the provider for your pinch rollers and ask.

Enjoy,
Rich P