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CT-F950 intermittent problem

Tripqzon said:
Hello pustelniakr,

Thanks for the wonderful tutorial.

I did notice that the idler does move from the front to the rear drive surface in play mode.

Anyway, the idler only seems to contact about half of the rear drive surface. Should the idler move back further so that the entire idler wheel comes in contact with the rear drive surface? Seems to me it should.

In fast mode, the idler does come in complete contact with the front drive.

Also, what do you recommend for cleaning the drive surfaces?

Paul
Click to expand...

The idler should make full contact with the rear drive surface during play.

The idler is driven back by the solenoid that lifts the heads in play mode. The button in the lower right of the cassette housing actuates the tape presence sensor and also mechanically enables the head mechanism to fully lift. If the idler is not moving fully to play mode, these are the areas to look.

The idler drive surfaces can be adequately cleaned with isopropl alcohol.

Rich P
 
I will look at those things Rich, but the deck played great all day yesterday.

I have been using isopropyl alcohol, so I'm ok there.

Thanks,
Paul
 
On my ct-f1250, The drop out in play mode turned out to be belts and a bad take up motor. With belts off, I realized I could grab the motor spindle and stop the motor which wouldn't turn again until I gave it a twist. It had bad spots on the armature. Once this problem started, it got progressively worse very quickly. Had to have the motor rebuilt, as no replacements are available.
As far as roller tension, if this was a suspect problem, can't you just move the springs down 1 notch to see if relieves the problem? Easy to try (on my model anyway) :)
 
pustelniakr said:
The idler should make full contact with the rear drive surface during play.

The idler is driven back by the solenoid that lifts the heads in play mode. The button in the lower right of the cassette housing actuates the tape presence sensor and also mechanically enables the head mechanism to fully lift. If the idler is not moving fully to play mode, these are the areas to look.

The idler drive surfaces can be adequately cleaned with isopropl alcohol.

Rich P
Click to expand...

I dissambled the tape mechanism last night because I noticed that the Idler mechanism seemed to stick. I cleaned and put fresh lithium grease where required on the "head base assembly". Now the idler mechanism does not stick and the idler wheel goes back further. The photo is of how it looks now after dissambly and cleaning/lubing. Does this look ok? I tried pushing it back further while running, but it gently goes back to this spot. No sticking or anything funny seems to be going on.
 
kcollins4 said:
On my ct-f1250, The drop out in play mode turned out to be belts and a bad take up motor. With belts off, I realized I could grab the motor spindle and stop the motor which wouldn't turn again until I gave it a twist. It had bad spots on the armature. Once this problem started, it got progressively worse very quickly. Had to have the motor rebuilt, as no replacements are available.
As far as roller tension, if this was a suspect problem, can't you just move the springs down 1 notch to see if relieves the problem? Easy to try (on my model anyway) :)
Click to expand...

Hi kcollins4,

If I grab the motor hard enough I can stop it, but it does start rotating when I let it go.

As far as roller tension, I could adjust the spring but prefer to use a gauge as I don't have a clue as to what the pressure is now. Also, I'm not convinced that is the problem. I feel that the problem lies in the idler assembly. And thanks to all the excellent suggestions and help from everyone, including yourself :) , I believe the problem may be mostly fixed. Only time will tell now.

I do still plan on replacing the pinch rollers as I believe they are original. I'll have to wait for them to be off backorder. OH WELL!!

Thanks,
Paul
 
Super picture.

Now show me the front face of the idler, with lifter mechanism. I want to see if you have the spring-wire positioned properly (it appears to be critical to idler contact pressure). I have one unit that has it and one unit that doesn't have it. It may be a post-mfg fix. I won't know till I get my service manual, which includes a post-mfg spool torque fix, as a supplement. The unit that doesn't have it also doesnt have a spool drive belt, so I won't know how well it works without it till I put on a belt. All I know is that the extra spring-wire makes all the difference in idler contact pressure.

Let me see what the face of your machine looks like (with the faceplate off, off course), then we can discuss further...

Rich P.
 
I see that your machine does not have the extra springwire. It may be a post-mfg fix, or an invention of a previous owner of the machine I have. When I get my service manual (w/ supplemental spool torque fix), I will let you know what I find. I have mod'd your picture to show where the springwire is. How do I post it here (I'm a newbie)?

Rich P
 
Here is where the extra springwire is on my unit in question. It really makes all the difference in the world to positive contact between the idler and its drive and to the drive surfaces of the spool tables. As I said, I will need to wait for my service manual to know if it is kosher or not. I have one CT-F900 with it and one without, and the one without also has no spool drive belt. It is obvious that with the extra springwire, the unit is much less susceptible to variations in drive surface or idler rubber condition.

One other thing I notice: I have 2 950s, 2 900s, and 2 1000s, at the moment and all of them have white spool caps, while yours appear to be black. What does that mean? I don't have a clue.

950idlerfrontview007640x480.jpg
 
I wonder if it has to do with manufacturing date?
Maybe updates to the units?
Different parts supplier?

What are the serial numbers on your 950's. Mine is: AH9308421
 
Tripqzon said:
I wonder if it has to do with manufacturing date?
Maybe updates to the units?
Different parts supplier?

What are the serial numbers on your 950's. Mine is: AH9308421
Click to expand...

Sorry. I was wrong. While at work, I thought I remembered my 950s having white spool caps, but they are, in fact, black.

Rich P
 
Well, I got the news I was expecting today about the Pinch Roller assemblies I ordered from PartStore.

They're no longer available :cry: . BIG SURPRISE there. NOT!!
 
pustelniakr said:
I've been getting them from Bob at http://www.vintage-electronics.cc/
Click to expand...

Thanks for the tip.

I bought a set from Bob and had no success with them. The deck would not stay in alignment. There was a lot more side-to-side movement than on the original roller assemblies. Also, they were a little narrower than the originals. I suspect that was the problem. My deck stays aligned just fine with the original rollers. I wanted to replace the originals because of there age but I'm still using them now.

I sold them to someone for their CT-F9191 and he apparently had no problems.

Paul
 
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Tripqzon said:
Thanks for the tip.

I bought a set from Bob and had no success with them. The deck would not stay in alignment. There was a lot more side-to-side movement than on the original roller assemblies. Also, they were a little narrower than the originals. I suspect that was the problem. My deck stays aligned just fine with the original rollers. I wanted to replace the originals because of there age but I'm still using them now.

I sold them to someone for their CT-F9191 and he apparently had no problems.

Paul
Click to expand...

You know, I had purchased several pinch rollers from Bob, but had not yet put them on. Now that you mention it, they are more narrow than the pinch rollers for the CT-F950 or CT-F900, and a bit more sloppy, horizontally. They are the same size as the pinch rollers for the CT-F1000. I will use them on the CT-F1000, but I guess I will have to sit on the ones I intended for the 900s and 950s. I'm going to contact Terry Witt and see if he can re-rubber the existing ones for me. I will be back when I find out. I will also contact Bob and and at least let him know what we have seen, so he can remove his recommendation of the the parts for 900s and 950s.

Rich P
 
Update:

I've been using the CT-F950 daily for the past 2 weeks and It's been running superb. Hasn't stopped unexpectedly once during that time.

I'm pretty happy about that. I really like this deck and would hate to see it non-functional.

Paul
 
Hey Paul, Glad to see that you got it going, I'm still digging thru tools and If I find the gauge I will send it out to you just to be able to double check the tension. By the looks of it, maybe I should send you one of my decks for service since you're now an expert on them, and we wouldn't want you to loose your touch with 'em :D
 
I have a 950 that I had ordered pinch rollers for. These came from Pioneer.I could not get the tape to track normally with the new rollers. I think the front and rear rollers are different if I remember correctly but it didn't make any difference. Anyway I threw the originals back in and the tape tracks perfectly. :confused:

Jim
 
Dynacoman said:
I have a 950 that I had ordered pinch rollers for. These came from Pioneer.I could not get the tape to track normally with the new rollers. I think the front and rear rollers are different if I remember correctly but it didn't make any difference. Anyway I threw the originals back in and the tape tracks perfectly. :confused:

Jim
Click to expand...

According to my service manual the pinch rollers are the same part number: RXB-005.

I don't understand it either. Did the Pioneer pinch roller assemblies have more horizontal (side to side) movement than the originals?

Hopefully Rich will here something from Bob at Vintage Electronics about this.

Paul
 
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