Mark’s CT-F850 arrived- some questions…

20tajk7

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It seems like there was a German seller on eBay who had nice looking pinch rollers, with sintered bronze bearings and all....
That German seller is well known for having high wow & flutter rollers, the rubber is usually too hard and the bearings are not sintered...
He has a lot of kits listed, sometimes for a particular decks there's more kits listed than the tape decks.
 

MarkWComer

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That German seller is well known for having high wow & flutter rollers, the rubber is usually too hard and the bearings are not sintered...
He has a lot of kits listed, sometimes for a particular decks there's more kits listed than the tape decks.
I've seen the complaints on AudioKarma, He's one to avoid.
You might find the rollers you need from https://fixyouraudio.com/product-category/spare-parts/pinch-rollers/pinch-rollers-size/
Sometimes these old CT-F's works better with a 13mm take up roller (more pressure to the capstan) instead of a 11mm.
I have to order from Slovakia? GOOD GRIEF! This is a dual capstan machine and there's a guide on the left side capstan, 13mm may be too big to fit. I guess it makes no difference since it's the capstan rotation that pulls the tape, the roller just pushes the tape against the capstan.
Ive bought many rollers from fixyouraudio. Good stuff. Pretty fast shipping also.
Still... that's way over in Slovakia!
Look into athan a bit before you buy. Plenty of negative reviews
Right- I hem and haw over paying $49 for one roller. Haven't seen any reviews yet, and they use urethane instead of rubber- don't know what the durometer is.
 

MarkWComer

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I've put the 13mm roller only on the right capstan, on my 850 the pinch roller springs were too weak, a bigger roller helped to get enough pressure.
There’s a series of holes on the bracket to adjust the pressure.
And… fiddling with that bracket… frustrating!
Replacing the idler tire was far worse, though…
 

laatsch55

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I've seen the complaints on AudioKarma, He's one to avoid.

I have to order from Slovakia? GOOD GRIEF! This is a dual capstan machine and there's a guide on the left side capstan, 13mm may be too big to fit. I guess it makes no difference since it's the capstan rotation that pulls the tape, the roller just pushes the tape against the capstan.

Still... that's way over in Slovakia!

Right- I hem and haw over paying $49 for one roller. Haven't seen any reviews yet, and they use urethane instead of rubber- don't know what the durometer is.
My bud Randy got a Sable German Shepard from Slovakia, beautiful, smart and plenty of tude...Tika
 

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J!m

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I would say you do NOT want a roller bearing on a pinch roller. You want a bushing.

The rollers I can foresee I traducing small “bumps” as they roll and I would be willing to be visible on a scope and perhaps audible.
 

MarkWComer

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The idler tire between the hubs was easy to access for disassembly, thought it would be a quick fix- until reassembly. Spring behind the wheel, a four- pin “castle” that interfaces with another one on the shaft. I had to completely remove and disassemble the transport to get it back together. That Э clamp kept flying loose- hours of frustration. Pulled a wire loose from the brake solenoid in the process.
FB91A911-5F31-4277-B49F-CB3F14F848B4.jpeg
The left pinch roller has a tape guide attached, will not allow a larger diameter for the roller. The bracket is spring loaded for tracking adjustment and the (nylon?) nut has a split. BE CAREFUL!
0AA38CFE-F1A0-4C11-982C-43A6B18ACEE7.jpeg
The roller guy wants $50 each for new tires, $10 for return shipping, so original brass bushings will stay, rollers measure at 11mm diameter. Will stay at OEM diameters.

So here’s a strike against ebay merchants- main drive belt could have been wider. Calibration cassette showed 2.99 kHz, so no complaint. New belts? But the idler tire and pinch rollers should have been serviced as well. Beautiful cosmetic condition, though. I’ve recorded a few tapes, and I’m surprised that the mix tape I made a while back for the forum went successfully.
 
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Mark
The Nylon Nut will strip out because they put to much glue on them. I stripped out some before knowing to try to remove the Glue.
if you need a Nut I bought Some, I also Have some Pitch roller since I also Rebuilding some Pioneer CT-F Now. They are not the easiest to figure out.
The idler tire size and belts lol are all over the map. if to tight they increase the wow and Flutter.

I'm Having problem w my Ct-F1250 which I Just got this week.
 
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Here is what I use, you can pm me
If the Nut is not Adjusted correctly the tape will curl up. Need a clear tape to see it and manaul pull th head up I also cut the plasic to see better. I since bought a Tool for this.
Also I have tried the Bigger pully this week it seemed to not help (I also soak the brass w oil over night)
much w wow And Flutter But I still need to play w it since I did not spend to much time on it.
I fixed a CT-F9191 which has no left pinch roller but a spring for tension. I found that the lower the tension the lower the wow and flutter . so for The Pioneer CT-F I set the spring to as low as possible I think I even changed to a weaker spring.
also a link for the wow and flutter sofware. Be warned,,,,Its like opening a can of worms LOL but still good to know
http://www.ant-audio.co.uk/index.php?cat=post&qry=library
Good luck
 

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Makymak

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A little late (but never is too late)

For belts and idle tires take a look at Webspareparts if they have any for your deck. I have used them and they offer good quality. Unfortunately, they don't have a variety of pinch rollers but you can ask! They are in Portugal but they charge reasonable shipping fees.

For your old pinch rollers: if I understand correctly, they have a barrel shape. I have seen this shape on some old decks and I think it's not a problem as long as it doesn't cause tape skewing. Or worse, tape chewing. As said before, you can sand them a little to bring at surface some fresh rubber but if they have been rock hard or cracked, no good. As for cleaning agent, isopropyl alcohol is quite safe. Never had a problem and I use it very frequently (I'm overdoing with cleaning). To be honest, I have used stronger solvents on pinch rollers and they stand great (terebinth oil mixed with alcohol or worse, benzine). Remember that if you replace the pinch rollers (especially the take up - left) this will introduce some azimuth deviation and it will need realignment.

For your old L-R imbalance, I wouldn't touch a calibration screw until I had access to a good level/azimuth test tape. Without a test tape no one can be sure if the imbalance is at playback or at recording part of the deck (or at both). You have to be sure that your playback levels are correctly so you have it as a reference to proceed to rec adjustments (levels and bias).

As for the transport, I wouldn't touch a screw unless I was sure it's misaligned. These dual capstan bastards need a very careful adjustments in order not to chew tapes. You will need an M300 gauge and a mirror cassette. These tools are quite expensive and don't worth it if you want to fix a single deck. You can always use a homemade "mirror" cassette if you know what to do (a cheap TDK D with clear shell is a good candidate). Also, the back tension plays it's part in tape path stability. I have learned all these the hard way (and some TDK SAs eaten).

You're deck is a beauty. Don't know it sonically but it's made at the heyday of the cassette era.

Happy new year!!!
 
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